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  • richardmitnick 2:00 pm on April 18, 2021 Permalink | Reply
    Tags: , , DOE’s Brookhaven National Laboratory(US), Don Lincoln-DOE's Fermi National Accelerator Laboratory (US), , , , ,   

    From Forbes Magazine : “Recent Reports Of Overturned Scientific Theory Are Premature” 

    From Forbes Magazine

    Apr 17, 2021

    .

    On April 7, 2021, the world’s scientific community watched with rapt attention as scientists based at Fermi National Accelerator Laboratory (US) presented a research result that the science media reported heavily. A new measurement disagreed in a very significant way with predictions. This disagreement could have been strong evidence that scientists would have to rethink their theory. That’s an exciting prospect, if it’s true. However, a theoretical paper [Leading hadronic contribution to the muon magnetic moment from lattice QCD] was released the same day as the experimental result that puts the entire situation in turmoil.

    The new experimental measurement involved the magnetic properties of subatomic particles called muons. Muons are essentially heavy cousins of the electron. Like the electron, the muon has both electric charge, and it spins. And any spinning electric charge creates a magnet. It is the strength of the magnet that researchers measured.

    It is possible for scientists to calculate the relationship between the strength of the magnet and the quantity describing the amount of spin. Ignoring some constants, the ratio of magnetic strength to amount of spin is called “g.” Using the quantum theory of the 1930s, it is easy to show that for electrons (and muons) that g is exactly equal to two (g = 2).

    History

    Measurements in 1947 [Physical Review Journals Archive] found that this prediction wasn’t quite right. The measured value of g was closer to 2.00238, or about 0.1% higher. This discrepancy could have been simply a measurement error, but it turned out that the difference was real. Shortly after measurement, a physicist by the name of Julian Schwinger used a more advanced form of quantum mechanics and found that the earlier prediction was incomplete and the correct value for g was indeed 2.00238. Schwinger shared the 1965 Nobel Prize in physics with Richard Feynman and Sin-Itiro Tomonaga, for developing this more advanced form of quantum mechanics.

    This more advanced form of quantum mechanics considered the effect of a charged particle on the space surrounding it. As one gets close to a charged particle, the electric field gets stronger and stronger. This strengthened field is accompanied by energy. According to Einstein’s theory of relativity, energy and mass are equivalent, so what happens is that the energy of the electric field can temporarily convert into a pair of particles, one matter and one antimatter. These two particles quickly convert back to energy, and the process repeats itself. In fact, there is so much energy involved in the electric field near, for example, an electron, that at any time there are many pairs of matter and antimatter particles at the same time.


    Quantum Foam

    A principle called the Heisenberg Uncertainty Principle applies here. This quantum principle says that pairs of matter and antimatter particles can appear, but only for a short time. Furthermore, the more massive the particles are, the harder it is for them to appear, and they live for a shorter amount of time.

    Because the electron is the lightest of the charged subatomic particles, they appear most often (along with their antimatter counterpart, called the positron). Thus, surrounding every electron is a cloud of energy from the electric field, and a second cloud of electrons and positrons flickering in and out of existence.

    Those clouds are the reason that the g factor for electrons or muons isn’t exactly 2. The electron or muon interacts with the cloud and this enhances the particle’s magnetic properties.

    So that’s the big idea. In the following decades, scientists tried to measure the magnetic properties of both electrons and muons more accurately. Some researchers have focused on measuring the magnetic properties of muons. The first experiment attempting to do this was performed in 1959 at the European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(CH) [CERN] laboratory in Europe. Because researchers were more interested in the new quantum corrections than they were with the 1930’s prediction, they subtracted off the “2” from the 1930s, and only looked at the excess. Hence this form of experiment is now called the “g – 2” experiment.

    The early experiment measuring the magnetic properties of the muon was not terribly precise, but the situation has improved over the years. In 2006, researchers at the DOE’s Brookhaven National Laboratory (US) , measured an extremely precise value for the magnetic properties of the muon.

    They measured exactly 2.0023318418, with an uncertainty of 0.0000000012. This is an impressive measurement by any standards. (The measurement numbers can be found at this URL (page 715).)

    The theoretical calculation for the magnetic properties of the muon is similarly impressive. A commonly accepted value for the calculation is 2.00233183620, with an uncertainty of 0.00000000086. The data and prediction agree, digit for digit for nine places.

    1
    Two measurements (red and blue) of the magnetic properties of the muon can be statistically combined into an experimental measurement (pink). This can be compared to a theoretical prediction (green), and prediction and measurement don’t agree. DOE’s Fermi National Accelerator Laboratory(US).

    Implications

    Such good agreement should be applauded, but the interesting feature is in a slight remaining disagreement. Scientists strip off all of the numbers that agree and remake the comparison. In this case, the theoretical number is 362.0 ± 8.6 and the experimental number is 418 ± 12. The two disagree by 56 with an uncertainty of 14.8.

    When one compares two independently generated numbers, one expects disagreement, but the agreement should be about the same size as the uncertainty. Here, the disagreement is 3.8 times the uncertainty. That’s weird and it could mean that a discovery has been made. Or it could mean that one of the two measurements is simply wrong. Which is it?

    To test the experimental result, another measurement was made. In April of 2021, researchers at Fermilab, America’s flagship particle physics laboratory, repeated the Brookhaven measurement. They reported a number that agreed with the Brookhaven measurement. When they combine their data and the Brookhaven data, they find a result of 2.00233184122 ± 0.00000000082. Stripped of the numbers that agree between data and theory, the current state of the art is:

    Theoretical prediction: 362.0 ± 8.6

    Experimental measurement: 412.2 ± 8.2

    This disagreement is substantial, and many have reported that this is good evidence that current theory will need to be revised to accommodate the measurement.

    However, this conclusion might be premature. On the same day that the experimental result was released, another theoretical estimate was published that disagrees with the earlier one. Furthermore, the new theoretical estimate is in agreement with the experimental prediction.

    3
    Two theoretical calculations are compared to a measurement (pink). The old calculation disagrees with the measurement, but the new lattice QCD calculation agrees rather well. The difference between the two predictions means any claims for a discovery are premature. Adapted from Science Magazine.

    How the theory is done

    Theoretical particle physics calculations are difficult to do. In fact, scientists don’t have the mathematical tools required to solve many problems exactly. Instead, they replace the actual problem with an approximation and solve the approximation.

    The way this is done for the magnetic properties of the muon is they look at the cloud of particles surrounding the muon and ask which of them is responsible for the largest effect. They calculate the contribution of those particles. Then they move to the next most important contributors and repeat the process. Some of the contributions are relatively easy, but some are not.

    While the particles surrounding the muon are often electrons and their antimatter electrons, some of the particles in the cloud are quarks, which are particles normally found inside protons and neutrons. Quarks are heavier than electrons, and they also interact with the strong nuclear charge. This strong interaction means that the quarks not only interact with the muon, the quarks interact with other quarks in the cloud. This makes it difficult to calculate their effect on the magnetic properties of the muon.

    So historically, scientists have used other data measurements to get an estimate of the quarks contribution to the muon’s magnetism. With this technique, they came up with the discrepancy between the prediction and measurement.

    However, a new technique has been employed which predicts the contribution caused by quarks. This new technique is called “lattice QCD,” where QCD is the conventional theory of strong nuclear force interactions. Lattice QCD is an interesting technique, where scientists set up a three dimensional grid and calculate the effect of the strong force on that grid. Lattice QCD is a brute force method and it has been successful in the past. But this is the first full attempt to employ the technique for the magnetic properties of muons.

    This new lattice QCD calculation differs from the earlier theoretical prediction. Indeed, it is much closer to the experimental result.

    So where does this leave us? When the Fermilab results were released, it appeared that the measurement and prediction disagreed substantially, suggesting that perhaps we needed to modify our theory to make it agree with data. However, now we have the unsettling situation that perhaps the theory wasn’t right. Maybe the new lattice QCD calculation is correct. In that case, there is no discrepancy between data and prediction.

    I think that the bottom line is that the entire situation is uncertain and it is too soon to draw any conclusion. The lattice QCD calculation is certainly interesting, but it’s new and also not all lattice QCD calculations agree. And the Fermilab version of the experiment measuring the magnetic properties of the muon is just getting started. They have reported a mere 6% of the total data they expect to eventually record and analyze.

    Precision measurements of the magnetic properties of muons have the potential to rewrite physics. But that’s only true if the measurement and predictions are both accurate and precise, and we’re not really ready to conclude that either are complete. It appears that the experimental measurement is pretty solid, although researchers are constantly looking for overlooked flaws. And the theory side is still a bit murky, with a lot of work required to understand the details of the lattice QCD calculation.

    I think it’s safe to say that we are still many years from resolving this question. This is, without a doubt, an unsatisfying state of affairs, but that’s science on the frontier of knowledge for you. We waited nearly two decades to get an improved measurement of the magnetic properties of muons. We can wait a few more years while scientists work hard to figure it all out.

    See the full article here .

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  • richardmitnick 1:49 pm on April 12, 2021 Permalink | Reply
    Tags: "Have Fermilab Scientists Broken Modern Physics?", DOE’s Brookhaven National Laboratory(US), , Don Lincoln at FNAL, , ,   

    From Forbes Magazine : “Have Fermilab Scientists Broken Modern Physics?” 

    From Forbes Magazine

    Apr 7, 2021
    Don Lincoln, FNAL

    1
    Researchers at DOE’s Fermi National Accelerator Laboratory(US) have made a measurement that could mean that scientists have to rethink their understanding of the rules that govern the subatomic world. Credit: Reidar Hahn/Fermilab.

    The past half century has been relatively uneventful for scientist’s understanding of the subatomic world. Theories developed in the 1960s and early 1970s have been combined into what is now called the Standard Model of Particle Physics.

    Standard Model of Particle Physics via Particle Fever movie.

    While there are a few unexplained phenomena (for example Dark Matter and Dark Energy), scientists have tested predictions of the standard model against measurements and the theory has passed with flying colors. Well, except for a few loose ends, including a decade-old disagreement between data and theory pertaining to the magnetic properties of a subatomic particle called the muon.

    Scientists have waited for two decades to see if this discrepancy is real. And today, the wait is over. A new measurement has been announced that goes a long way towards telling us if the venerable theory will need revising.

    Muons are ephemeral subatomic particles, much like the more familiar electron. Like their electron brethren, muons have electric charge and spin. They also decay in about a millionth of a second, which makes them challenging to study.

    Objects that are both electrically charged and spin are also magnets, and muons are no exception. Physicists call the magnetic strength of a magnet made in this way the “magnetic moment” of a particle. One can predict the magnetic moment of both electrons and muons using the conventional quantum mechanics of the 1930s. However, when the first measurement of the magnetic moment of the electron was accomplished in 1948, it was 0.1% too high. The cause of this tiny discrepancy was traced to some truly odd quantum behavior. At the very smallest size scales, space is not quiescent. Instead, it’s a writhing mess, with pairs of particles and antimatter particles appearing and disappearing in the blink of an eye.

    We can’t see this frenetic sea of objects appearing and disappearing, but if you accept that it is true and calculate its effect on the magnetic moment of both muon and electron, it is in exact agreement with the tiny, 0.1%, excess, first reported back in 1948.

    In the intervening 70 years, scientists have both predicted and measured the magnetic moment of the both the muon and electron to a staggering precision of twelve digits of accuracy. And measurement and prediction agree, digit for digit, for the first ten digits. But they disagree for the last two. Furthermore, the disagreement is larger than can be explained by the uncertainty on either the prediction or measurement. It appears that the two disagree.

    If data and theory disagree, one (or both) is wrong. It’s possible that the measurement was inaccurate in some way. It’s also possible that the calculation has an error, or the calculation doesn’t include all relevant effects. If that last option is true – overlooked effects – it means that the standard model of particle physics is incomplete. There is at least something new and unexpected.

    For the past two decades, the best measurement of the magnetic moment of the muon is one made by the Muon g-2 experiment at DOE’s Brookhaven National Laboratory (US), on Long Island, New York. (The experiment is pronounced “muon gee minus two.”) The “g-2” is historical and refers specifically only to the 0.1% excess over the prediction of standard quantum mechanics. Standard quantum mechanics predicts that the magnetic moment of the electron or muon is “g.”

    The discrepancy between theory and measurement was pretty large. If you divided the difference by the combined experimental and theoretical uncertainty, the result was 3.7σ. Scientists call that ratio “sigma,” and use sigma to rate how important a measurement is. If under 3σ, scientists say it is not interesting. If between 3σ and 5σ, scientists start to get interested and call that state of affairs to be “evidence of a discovery.” If above 5σ, scientists are confident that the discrepancy is real and meaningful. For sigmas above 5, scientists usually title their papers as “Observation of…” 5σ is a big deal.

    So, the Muon g-2 experiment at Brookhaven reported a 3.7σ, which is a big deal, but not big enough to be super excited. Another measurement was needed.

    However, the accelerator facility at Brookhaven had done all it could do. A more powerful source of muons was needed. Enter Fermilab, America’s flagship particle physics laboratory, located just west of Chicago. Fermilab could make more muons than Brookhaven could.

    So, researchers bundled up the g-2 apparatus and sent it to Fermilab.

    DOE’s Fermi National Accelerator Laboratory(US) G-2 magnet from DOE’s Brookhaven National Laboratory(US) finds a new home in the FNAL Muon G-2 experiment. The move by barge and truck.

    Fermi National Accelerator Laboratory(US) Muon g-2 studio. As muons race around a ring at the , their spin axes twirl, reflecting the influence of unseen particles.

    Because the g-2 apparatus is shaped like a plate, but 50’ across and 6’ thick, it couldn’t easily be shipped on roads. So, the equipment was put on a barge that went down the east coast of the U.S., up the Mississippi and some of its tributaries, until it was at a debarkation point near Fermilab in northeast Illinois. Then the equipment was put on a flatbed truck and driven in the dead of night to Fermilab. It took two nights, but on July 26, 2013, the g-2 experiment was located at Fermilab.

    Scientists then set to work, building the buildings, accelerator, and infrastructure necessary to perform an improved measurement. In the spring of 2018, the scientists began taking data. Each year, the experiment operates for many months, collecting data. Each year is called a “run” and the Fermilab Muon g-2 experiment is expected to make five runs, including a few in the future.

    The measurement is incredibly precise. They are measuring something with twelve digits of accuracy. That is like measuring the distance around the Earth to a precision a little smaller than the thickness of a sheet of computer printer paper.

    This recent measurement using the g-2 equipment at Fermilab confirmed the earlier measurement at Brookhaven. When the data from the two laboratories are combined, the discrepancy between data and theory is now 4.2σ, tantalizingly close to the desired “Observation of” standard, but not quite there.

    On the other hand, the measurement reported today is based on a single run. Given improvements to the accelerator and facilities, researchers expect to record sixteen times more data than has been reported so far. If the measurement involving all of the data is consistent with the measurement reported today, and the precision of the measurement improves as expected, it is very likely that the g-2 experiment will definitively prove that the standard model is not a complete theory. That conclusion is premature, but it is looking likely.

    So, what does this mean? The most robust conclusion one can draw is that if future measurements tell the same story, the standard model needs modification. It appears that there is something going on in the subatomic realm that is giving the muon a different magnetic moment than the standard model predicts.

    What could that new physics be? Well, it is unlikely that the standard model will need to be completely discarded. It simply works too well on other measurements that aren’t quite as precise. What is more likely is that there exists an unknown class of subatomic particles that have not yet been discovered. One possibility is that an extension of the standard model, called supersymmetry, is true.

    Standard Model of Supersymmetry

    If supersymmetry is real, it predicts twice as many subatomic particles as the standard model. In a pure supersymmetric theory, these new particles would have the same mass as the known ones, but this is ruled out by many measurements. However, there could be a modified version of supersymmetry, which makes the undiscovered cousin particles heavier than the known ones. If true, it would modify the prediction of the magnetic moment of the muon in just the right way to make data and theory agree.

    3
    Particle physics supersymmetry. Conceptual illustration showing the standard model particles with their heavier superpartners introduced by the supersymmetry (SUSY) principle. In supersymmetry force and matter are treated identically. Using supersymmetry, physicists may find solutions for problems such as the weakness of gravity, the low mass of the Higgs boson and the unification of forces or even dark matter. Credit: Getty.

    But supersymmetry is just one possible explanation. The simple fact is that there could be many different kinds of subatomic particles that haven’t been discovered. Perhaps some new theory that explains dark matter might be relevant. Or something entirely unimagined by anyone at this point. We just don’t know.

    But not knowing isn’t bad. It just means that there are new things to learn, problems to solve. Theoretical physicists are already thinking through what might be the implications of the new measurement and what sorts of theories might explain it. The important thing is to accept that a venerable and long-accepted theory is incomplete, and that we need to rethink things. That’s how science is done.

    But I’m getting ahead of myself. The researchers need to analyze the other runs and verify that the more precise results validate today’s measurement. But things are definitely beginning to look interesting.

    See the full article here .

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  • richardmitnick 12:26 pm on April 12, 2021 Permalink | Reply
    Tags: , DOE’s Brookhaven National Laboratory(US), , Muon g−2 Collaboration(s), Muon’s Escalating Challenge to the Standard Model, , ,   

    From Physics : Muons 

    About Physics

    From Physics

    Muon’s Escalating Challenge to the Standard Model

    April 7, 2021
    Priscilla Cushman

    DOE’s Fermi National Accelerator Laboratory(US) G-2 magnet from DOE’s Brookhaven National Laboratory(US) finds a new home in the FNAL Muon G-2 experiment. The move by barge and truck.

    1
    Figure 1: View of DOE’s Fermi National Accelerator Laboratory(US)’s Muon g−2 ring, where the precession of muons in a magnetic field is used to measure the muon magnetic moment. Credit: Reidar Hahn/Fermilab

    Twenty years ago, the DOE’s Brookhaven National Laboratory(US) Muon g−2 experiment measured a value of the anomalous magnetic moment of the muon that disagreed by several parts per million with calculations based on the standard model (SM) of particle physics [1]. Physicists had long understood that the SM was incomplete, but the Muon g−2 experiment provided a measurable discrepancy between a very precise quantum-mechanical calculation and an equally precise measurement of a fundamental constant. The 2.7σ discrepancy was exciting in an era when the only news coming out of other major facilities—from the Large Electron-Positron Collider to the Tevatron—was how well the SM worked. Data taking was halted after the 2001 run, since reducing significantly the statistical uncertainty would have required a higher-intensity muon beam, and reducing the systematic uncertainty would have required major engineering upgrades [2]. Meanwhile, theorists continued to improve the accuracy of the calculation, which increased the significance of the mismatch to 3.7σ as of 2020 [3]. It was clearly time to revisit the experimental side of the dilemma.

    Today, the next-generation Muon g−2 Experiment at DOE’s Fermi National Accelerator Laboratory(US)(Fermilab) releases its first results [4], confirming the mean value of the discrepancy found two decades earlier. With this new independent measurement, the world average now stands at a more convincing 4.2σ departure from the SM. This mismatch could be the effect of new particles and new interactions that are considered by many natural SM extensions, such as supersymmetry, dark matter, and heavy neutrinos.

    The magnetic moment of a particle is proportional to its spin and to its g-factor, which is exactly 2 for a point particle with half-integer spin. However, the muon is constantly interacting with virtual particles, which wink in and out of existence with quantum-mechanical probabilities calculable to an incredible precision. This fluctuating cloud of particles modifies the g-factor. The amount by which it differs from 2 is characterized by the anomaly a=(g−2)∕2, which is why the experiment is called Muon g−2. If the muon—a quantum-mechanical spinning top—is placed in a magnetic field, its spin will precess about the field direction at a frequency that depends on the charge distribution of those virtual particles. Measuring the precession frequency provides a determination of the anomaly and thereby of the overall effect of the virtual particles.

    The Fermilab Muon g−2 Experiment (Fig. 1) follows the same technique used at Brookhaven. Polarized muons, whose spins are aligned with their direction of motion, are injected into a 14.2-m-diameter storage ring where they circle thousands of times thanks to their relativistically-stretched lifetime. As they decay, the muons spit out positrons that are detected by calorimeters lining the inner circumference of the ring. Inside the ring, the 1.45-T magnetic field that keeps the muons traveling in a circle also provides the magnetic torque that causes spin precession.

    If g were exactly 2, the precession period would equal the cyclotron period, and the muon spin direction would rotate in lockstep with the muon momentum vector. Instead, the spin direction gradually gets out of sync, taking about 27 turns before realigning with the momentum. This frequency difference is the anomalous precession ωa. Since the decay positrons are preferentially emitted in the direction of the muon spin, their spectrum shifts to higher energies when the spin direction is aligned with the momentum. This shift produces a modulation in the number of positrons detected by the calorimeters.

    The storage ring is a marvel of modern engineering. A concentric pair of superconducting coils creates a uniform vertical field inside the ring, while four electrostatic quadrupole plates serve as focusing elements. The design of the ring was optimized for muons with a momentum of 3.09 GeV/c, since at this “magic momentum” the electrostatic quadrupoles do not disturb the precession frequency to first order. This feature provided such an advantage that researchers opted to keep the original Brookhaven ring instead of exploring other design options. In 2013, the ring was dismantled, and the delicate superconducting coils were shipped over sea and land from Brookhaven to Fermilab [5]. Thanks to precision positioning of the 72 individual pole pieces and to the addition of programmable current shims, the reassembled magnet achieved a threefold improvement in azimuthal field uniformity over its earlier incarnation at Brookhaven.

    The anomaly can be written as the ratio of two frequencies, measured to high precision by the experiment. The first is the measurement of the anomalous precession ωa derived from analysis of the calorimeter response [6]. The second is a measurement of the magnetic field [7] along the muons’ path, derived from the precession frequency ωp of protons contained in fixed and moveable NMR probes (see Measuring the Field that Measures the Muon). Deriving both frequencies requires extremely precise knowledge of the muon beam dynamics [8], since each muon path samples a slightly different magnetic field and each calorimeter measures a positron modulation averaged over different muon orbits. The researchers obtained such information with extensive simulations, with corrections for eddy currents and mechanical vibrations, and with the use of data from straw chambers that tracked the positrons back to their muon parents. The anomaly can then be written in terms of the ratio R′=ωa∕ω˜′p, where ω˜′p is a calibrated, muon-weighted, and magnetic-field-averaged frequency derived from ωp. The obtained precisions for the numerator and for the denominator of R′ (438 ppb and 56 ppb, respectively) resulted in a 460-ppb precision in the determination of the anomaly.

    The fact that R′ is a ratio of frequencies led to a novel blinding process designed to prevent the researchers from subconsciously steering the analysis to favor a particular answer. Two gatekeepers from outside the collaboration applied a secret frequency offset to a clock used to calibrate ωa, revealing the value of the offset only after the data analysis was completed [9]. Confirmation of the previous result was never a foregone conclusion. As someone who has gone through a similar process at Brookhaven, I know how exciting—and somewhat terrifying—it can be to finally un-blind your data. Once you “open the box,” you can neither retract nor revise your answer, so you have to trust that all the systematic sources of error have been accounted for.

    Fermilab’s new results provide compelling evidence that the answer obtained at Brookhaven was not an artifact of some unexamined systematics but a first glimpse of beyond-SM physics. While the results announced today are based on the 2018 run, data taken in 2019 and 2020 are already under analysis. We can look forward to a series of higher-precision results involving both positive and negative muons, whose comparison will provide new insights on other fundamental questions, from CPT violation to Lorentz invariance [10]. This future muon g−2 campaign will lead to a fourfold improvement in the experimental accuracy, with the potential of achieving a 7-sigma significance of the SM deficit.

    Other planned experiments will weigh in over the next decade, such as the E34 experiment at J-PARC, which employs a radically different technique for measuring g−2 [11]. E34 will also measure the muon electric dipole moment, offering a complementary window into SM deviations. In addition, the muon g−2 anomaly is not alone in suggesting “cracks” in the SM. These cracks have just gotten wider with LHCb’s 3.1σ observation of the breakdown of lepton universality in beauty-quark decays [12]. Each glimpse of such anomalies (see The Era of Anomalies) provides new clues to the ultimate physics that governs our Universe, for which the SM is just the best “effective theory” up until now.

    References

    G. W. Bennett et al. (Muon g-2 Collaboration), “Final report of the E821 muon anomalous magnetic moment measurement at BNL,” Phys. Rev. D 73, 072003 (2006).
    J. Grange et al., “Muon (g-2) Technical Design Report,” arXiv:1501.06858.
    T. Aoyama et al., “The anomalous magnetic moment of the muon in the Standard Model,” Phys. Rep. 887, 1 (2020).
    B. Abi et al. (Muon g-2 Collaboration), “Measurement of the positive muon anomalous magnetic moment to 0.46 ppm,” Phys. Rev. Lett. 126, 141801 (2021).
    https://muon-g-2.fnal.gov/bigmove/.
    T. Albahri et al. (Muon g-2 Collaboration), “Measurement of the anomalous precession frequency of the muon in the Fermilab Muon g−2 Experiment,” Phys. Rev. D 103, 072002 (2021).
    T. Albahri et al. (Muon g-2 Collaboration), “Magnetic-field measurement and analysis for the Muon g−2
    Experiment at Fermilab,” Phys. Rev. A 103, 042208 (2021).
    T. Albahri et al. (Muon g-2 Collaboration), “Beam dynamics corrections to the Run-1 measurement of the muon anomalous magnetic moment at Fermilab,” Phys. Rev. Accel. Beams (to be published).

    R. Bluhm et al., “CPT and Lorentz Tests with Muons,” Phys. Rev. Lett. 84, 1098 (2000); “Testing CPT with Anomalous Magnetic Moments,” 79, 1432 (1997).
    M. Abe et al., “A new approach for measuring the muon anomalous magnetic moment and electric dipole moment,” Prog. Theor. Exp. Phys. 2019 (2019).
    R. Aaij et al. (LHCb Collaboration ), “Test of lepton universality in beauty-quark decays,” arXiv:2103.11769.

    See the full article here .

    Measuring the Magnet that Measures the Muon

    April 7, 2021
    Michael Schirber

    To precisely measure the magnetic moment of the muon, physicists first needed to precisely measure the field produced by the 680-ton magnet that guides the muons.

    2
    Argonne National Laboratory
    Image of the trolley carrying the nuclear magnetic resonance probes used to measure the magnetic field in the Muon g−2 experiment. Credit: DOE’s Argonne National Laboratory(US).

    The basic idea of the Muon g−2 experiment at Fermi National Accelerator Laboratory (Fermilab), Illinois, is to detect the wobbles of microscopic magnets traveling around a 15-m-wide ring-shaped magnet. The tiny magnets are elementary particles called muons, and the wobbles reveal the magnetic strength, or moment, of the muons. The results reported today don’t match up with standard model predictions, which is making the muon the talk of the town.

    However, there’s a less talked about aspect to this development, and that’s the giant magnet that corrals the muons. The Muon g−2 scientists constantly keep tabs on this 1.45-tesla magnet using hundreds of nuclear magnetic resonance (NMR) sensors, some of which ride on a small trolley that rolls around the experiment. The effort has helped bring down the uncertainties in the field measurement to 114 parts per billion—a nearly twofold improvement over the previous muon experiment, where the magnetic-moment discrepancy was first observed.

    That experiment, which ran at Brookhaven National Laboratory, New York, used the same giant magnet that Muon g−2 is using today. The magnet was shipped 3200 miles from Brookhaven to Fermilab in 2013. The magnet’s main components are a combination of iron chunks and superconducting coils that produce a vertical field inside the muon storage ring—a 45-m-long circular path tucked within the magnet’s metal structure. The field steers the muons along a circular path, while also causing their magnetic moments to wobble, or precess. To obtain the muon’s magnetic moment, the Muon g−2 Collaboration divides the frequency of this precession by the strength of the magnetic field. “The spin precession frequency is the more familiar part of the experiment,” says Peter Winter from Argonne National Laboratory, Illinois. “But measuring the magnetic field is just as important.”

    Winter and his colleagues have developed an elaborate set of protocols for measuring the magnetic field, which they don’t quantify in terms of teslas but in terms of the precession frequency of a proton exposed to the same field while sitting at the center of a spherical water sample at 34.7∘C. “It’s a mouthful,” admits David Kawall from the University of Massachusetts, Amherst. But this proton-in-water frequency is a commonly used standard in NMR measurements. Kawall compares it to the metal cylinder in Paris that was—until recently—the kilogram standard. “We know how to take what our probes measure and interpret it in terms of this NMR standard,” Kawall says.

    One of the complications in measuring the field of the giant magnet is that it varies both in space and in time because of structural inhomogeneities and temperature variations. “If the storage ring were perfectly homogeneous, then you could just put in one probe, measure the field, and you’d be done,” Kawall says. The spatial deviations around the ring are of order 14 to 17 parts per million—which isn’t terrible for a giant iron magnet, he says. In fact, the deviations are 3 times smaller than for the Brookhaven experiment, thanks in part to a meticulous “shimming” process, in which 8000 hand-cut strips of iron foil were glued onto the magnet structure in 2016. The foil strips leveled out the field—like sheets of paper placed under the legs of a wobbly table. “These small pieces can make a sizable change in the magnetic field,” says David Flay from DOE’s Thomas Jefferson National Accelerator Facility(US) in Virginia.

    Even with all the adjustments made to the magnet, the researchers need a detailed map of the field. For that, they have installed an array of 378 NMR probes around the magnet ring. These fixed probes can provide continuous readings of the field, but they sit several centimeters away from the muon beam. To measure the actual field that the muons experience, Winter and his colleagues seated 17 NMR probes inside a 50-cm-long trolley. Every three days—when the muon beam is shut off—the cylindrical trolley is dragged out of a small garage and pulled around the beam path by a set of cables. Although it carries no passengers, the trolley has a full itinerary with 9000 “destinations” where it records field measurements. “The trolley can map the field at finer intervals than the fixed probes, giving us a better measurement of the field distribution distribution where the muons move.” Winter says. Poking along at a speed of roughly 1 cm/s, the trolley takes about one hour to complete a one-way trip around the 45-m circumference.

    The probes in the trolley, as well as the fixed ones, are 10-cm-long cylinders filled with a dab of petroleum jelly. Protons in the jelly are made to precess through the application of a radio pulse, and this precession is detected to determine the magnetic field around the probe. “We use petroleum jelly because the proton precession recovery time is faster than in water, allowing us to measure the field every 1.4 seconds,” Flay explains. To convert the proton-in-jelly frequency measurement to the standard proton-in-water frequency, Flay and Kawall developed a water-based NMR probe that they station at a single stop along the trolley path. During the calibration process, the trolley moves in, takes a measurement at a well-defined position, and moves out. Then, the calibration probe executes the exact same maneuvers, and the readings are compared. This “hokey pokey dance” is repeated over and over for six hours to obtain a reliable conversion factor for each probe in the trolley.

    “I think the magnetic field measurement is sometimes under-appreciated in this experiment because one might think it just involves placing a sensor somewhere,” Winter says. “In reality, it’s a long chain of complex measurements.” The researchers continue to work on reducing the measurement uncertainties, with the goal of reaching 70 parts per billion precision for the magnetic field and 140 parts per billion for the muon magnetic moment. The experiment is a rich mix of high-energy physics, atomic physics, and beam dynamics, says Kawall, who worked on the Brookhaven experiment before joining the Fermilab effort. “It’s so interesting, you could spend a whole career working on it to try and understand it,” he says.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Physicists are drowning in a flood of research papers in their own fields and coping with an even larger deluge in other areas of physics. How can an active researcher stay informed about the most important developments in physics? Physics highlights a selection of papers from the Physical Review journals. In consultation with expert scientists, the editors choose these papers for their importance and/or intrinsic interest. To highlight these papers, Physics features three kinds of articles: Viewpoints are commentaries written by active researchers, who are asked to explain the results to physicists in other subfields. Focus stories are written by professional science writers in a journalistic style and are intended to be accessible to students and non-experts. Synopses are brief editor-written summaries. Physics provides a much-needed guide to the best in physics, and we welcome your comments.

     
  • richardmitnick 9:14 pm on March 19, 2021 Permalink | Reply
    Tags: "Building tough 3D nanomaterials with DNA", 3D DNA-nanoparticle architecture, , , DOE’s Brookhaven National Laboratory(US), Fu Foundation School of Engineering and Applied Science, ,   

    Fu Foundation School of Engineering and Applied Science via phys.org: “Building tough 3D nanomaterials with DNA” 

    From Fu Foundation School of Engineering and Applied Science

    Columbia U bloc

    At Columbia University

    via


    phys.org

    March 19, 2021

    1
    Mineralization of 3D lattice formed by DNA tetrahedra (about 30 nm) and gold nanoparticle into all-inorganic 3D silica-Au replicas with preserved architecture. Credit: Oleg Gang/Columbia Engineering.

    Columbia Engineering researchers, working with DOE’s Brookhaven National Laboratory(US), report today that they have built designed nanoparticle-based 3D materials that can withstand a vacuum, high temperatures, high pressure, and high radiation. This new fabrication process results in robust and fully engineered nanoscale frameworks that not only can accommodate a variety of functional nanoparticle types but also can be quickly processed with conventional nanofabrication methods.

    “These self-assembled nanoparticles-based materials are so resilient that they could fly in space,” says Oleg Gang, professor of chemical engineering and of applied physics and materials science, who led the study published today by Science Advances. “We were able to transition 3D DNA-nanoparticle architectures from liquid state—and from being a pliable material—to solid state, where silica re-enforces DNA struts. This new material fully maintains its original framework architecture of DNA-nanoparticle lattice, essentially creating a 3D inorganic replica. This allowed us to explore—for the first time—how these nanomaterials can battle harsh conditions, how they form, and what their properties are.”

    Material properties are different at the nanoscale and researchers have long been exploring how to use these tiny materials—1,000 to 10,000 times smaller than the thickness of a human hair—in all kinds of applications, from making sensors for phones to building faster chips for laptops. Fabrication techniques, however, have been challenging in realizing 3D nano-architectures. DNA nanotechnology enables the creation of complexly organized materials from nanoparticles through self-assembly, but given the soft and environment-dependent nature of DNA, such materials might be stable under only a narrow range of conditions. In contrast, the newly formed materials can now be used in a broad range of applications where these engineered structures are required. While conventional nanofabrication excels in creating planar structures, Gang’s new method allows for fabrication of 3D nanomaterials that are becoming essential to so many electronic, optical, and energy applications.

    Gang, who holds a joint appointment as group leader of the Soft and Bio Nanomaterials Group at Brookhaven Lab’s Center for Functional Nanomaterials, is at the forefront of DNA nanotechnology, which relies on folding DNA chain into desired two and three-dimensional nanostructures. These nanostructures become building blocks that can be programmed via Watson-Crick interactions to self-assemble into 3D architectures. His group designs and forms these DNA nanostructures, integrates them with nanoparticles and directs the assembly of targeted nanoparticle-based materials. And, now, with this new technique, the team can transition these materials from being soft and fragile to solid and robust.

    This new study demonstrates an efficient method for converting 3D DNA-nanoparticle lattices into silica replicas, while maintaining the topology of the interparticle connections by DNA struts and the integrity of the nanoparticle organization. Silica works well because it helps retain the nanostructure of the parent DNA lattice, forms a robust cast of the underlying DNA and does not affect nanoparticles arrangements.

    “The DNA in such lattices takes on the properties of silica,” says Aaron Michelson, a Ph.D. student from Gang’s group. “It becomes stable in air and can be dried and allows for 3D nanoscale analysis of the material for the first time in real space. Moreover, silica provides strength and chemical stability, it’s low-cost and can be modified as needed—it’s a very convenient material.”

    2
    Different types of nanoscale lattices formed with polyhedra DNA nano-frames (tetrahedra, cubes, and octahedra) and gold nanoparticle are mineralized with controllable silica coating thicknesses (from about 5nm to a full space-filling). Credit: Oleg Gang/Columbia Engineering.

    To learn more about the properties of their nanostructures, the team exposed the converted to silica DNA-nanoparticles lattices to extreme conditions: high temperatures above 1,0000C and high mechanical stresses over 8GPa (about 80,000 times more than atmosphere pressure, or 80 times more than at the deepest ocean place, the Mariana trench), and studied these processes in-situ. To gauge the structures’ viability for applications and further processing steps, the researchers also exposed them to high doses of radiation and focused ion beams.

    “Our analysis of the applicability of these structures to couple with traditional nanofabrication techniques demonstrates a truly robust platform for generating resilient nanomaterials via DNA-based approaches for discovering their novel properties,” Gang notes. “This is a big step forward, as these specific properties mean that we can use our 3D nanomaterial assembly and still access the full range of conventional materials processing steps. This integration of novel and conventional nanofabrication methods is needed to achieve advances in mechanics, electronics, plasmonics, photonics, superconductivity, and energy materials.”

    Collaborations based on Gang’s work have already led to novel superconductivity and conversion of the silica to conductive and semiconductive media for further processing. These include an earlier study published by Nature Communications and one recently published by Nano Letters. The researchers are also planning to modify the structure to make a broad range of materials with highly desirable mechanical and optical properties.

    “Computers have been made with silicon for over 40 years,” Gang adds. “It took four decades to push the fabrication down to about 10 nm for planar structures and devices. Now we can make and assemble nanoobjects in a test tube in a couple of hours without expensive tools. Eight billion connections on a single lattice can now be orchestrated to self-assemble through nanoscale processes that we can engineer. Each connection could be a transistor, a sensor, or an optical emitter—each can be a bit of data stored. While Moore’s law is slowing, the programmability of DNA assembly approaches is there to carry us forward for solving problems in novel materials and nanomanufacturing. While this has been extremely challenging for current methods, it is enormously important for emerging technologies.”

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Fu Foundation School of Engineering and Applied Science is the engineering and applied science school of Columbia University. It was founded as the School of Mines in 1863 and then the School of Mines, Engineering and Chemistry before becoming the School of Engineering and Applied Science. On October 1, 1997, the school was renamed in honor of Chinese businessman Z.Y. Fu, who had donated $26 million to the school.

    The Fu Foundation School of Engineering and Applied Science maintains a close research tie with other institutions including National Aeronautics and Space Administration(US), IBM, Massachusetts Institute of Technology(US), and The Earth Institute. Patents owned by the school generate over $100 million annually for the university. Faculty and alumni are responsible for technological achievements including the developments of FM radio and the maser.

    The School’s applied mathematics, biomedical engineering, computer science and the financial engineering program in operations research are very famous and ranked high. The current faculty include 27 members of the National Academy of Engineering(US) and one Nobel laureate. In all, the faculty and alumni of Columbia Engineering have won 10 Nobel Prizes in physics, chemistry, medicine, and economics.

    The school consists of approximately 300 undergraduates in each graduating class and maintains close links with its undergraduate liberal arts sister school Columbia College which shares housing with SEAS students.

    Original charter of 1754

    Included in the original charter for Columbia College was the direction to teach “the arts of Number and Measuring, of Surveying and Navigation […] the knowledge of […] various kinds of Meteors, Stones, Mines and Minerals, Plants and Animals, and everything useful for the Comfort, the Convenience and Elegance of Life.” Engineering has always been a part of Columbia, even before the establishment of any separate school of engineering.

    An early and influential graduate from the school was John Stevens, Class of 1768. Instrumental in the establishment of U.S. patent law. Stevens procured many patents in early steamboat technology; operated the first steam ferry between New York and New Jersey; received the first railroad charter in the U.S.; built a pioneer locomotive; and amassed a fortune, which allowed his sons to found the Stevens Institute of Technology.

    When Columbia University first resided on Wall Street, engineering did not have a school under the Columbia umbrella. After Columbia outgrew its space on Wall Street, it relocated to what is now Midtown Manhattan in 1857. Then President Barnard and the Trustees of the University, with the urging of Professor Thomas Egleston and General Vinton, approved the School of Mines in 1863. The intention was to establish a School of Mines and Metallurgy with a three-year program open to professionally motivated students with or without prior undergraduate training. It was officially founded in 1864 under the leadership of its first dean, Columbia professor Charles F. Chandler, and specialized in mining and mineralogical engineering. An example of work from a student at the School of Mines was William Barclay Parsons, Class of 1882. He was an engineer on the Chinese railway and the Cape Cod and Panama Canals. Most importantly he worked for New York, as a chief engineer of the city’s first subway system, the Interborough Rapid Transit Company. Opened in 1904, the subway’s electric cars took passengers from City Hall to Brooklyn, the Bronx, and the newly renamed and relocated Columbia University in Morningside Heights, its present location on the Upper West Side of Manhattan.

    Columbia U Campus

    Columbia University was founded in 1754 as King’s College by royal charter of King George II of England. It is the oldest institution of higher learning in the state of New York and the fifth oldest in the United States.

    University Mission Statement

    Columbia University is one of the world’s most important centers of research and at the same time a distinctive and distinguished learning environment for undergraduates and graduate students in many scholarly and professional fields. The University recognizes the importance of its location in New York City and seeks to link its research and teaching to the vast resources of a great metropolis. It seeks to attract a diverse and international faculty and student body, to support research and teaching on global issues, and to create academic relationships with many countries and regions. It expects all areas of the University to advance knowledge and learning at the highest level and to convey the products of its efforts to the world.

    Columbia University is a private Ivy League research university in New York City. Established in 1754 on the grounds of Trinity Church in Manhattan Columbia is the oldest institution of higher education in New York and the fifth-oldest institution of higher learning in the United States. It is one of nine colonial colleges founded prior to the Declaration of Independence, seven of which belong to the Ivy League. Columbia is ranked among the top universities in the world by major education publications.

    Columbia was established as King’s College by royal charter from King George II of Great Britain in reaction to the founding of Princeton College. It was renamed Columbia College in 1784 following the American Revolution, and in 1787 was placed under a private board of trustees headed by former students Alexander Hamilton and John Jay. In 1896, the campus was moved to its current location in Morningside Heights and renamed Columbia University.

    Columbia scientists and scholars have played an important role in scientific breakthroughs including brain-computer interface; the laser and maser; nuclear magnetic resonance; the first nuclear pile; the first nuclear fission reaction in the Americas; the first evidence for plate tectonics and continental drift; and much of the initial research and planning for the Manhattan Project during World War II. Columbia is organized into twenty schools, including four undergraduate schools and 15 graduate schools. The university’s research efforts include the Lamont–Doherty Earth Observatory, the Goddard Institute for Space Studies, and accelerator laboratories with major technology firms such as IBM. Columbia is a founding member of the Association of American Universities and was the first school in the United States to grant the M.D. degree. With over 14 million volumes, Columbia University Library is the third largest private research library in the United States.

    The university’s endowment stands at $11.26 billion in 2020, among the largest of any academic institution. As of October 2020, Columbia’s alumni, faculty, and staff have included: five Founding Fathers of the United States—among them a co-author of the United States Constitution and a co-author of the Declaration of Independence; three U.S. presidents; 29 foreign heads of state; ten justices of the United States Supreme Court, one of whom currently serves; 96 Nobel laureates; five Fields Medalists; 122 National Academy of Sciences members; 53 living billionaires; eleven Olympic medalists; 33 Academy Award winners; and 125 Pulitzer Prize recipients.

     
  • richardmitnick 9:09 am on March 19, 2021 Permalink | Reply
    Tags: "Science Requirements and Detector Concepts for the Electron-Ion Collider: EIC Yellow Report", "Scientists Describe Detector Goals for Electron-Ion Collider (EIC)", , , DOE’s Brookhaven National Laboratory(US), ,   

    From DOE’s Brookhaven National Laboratory(US): “Scientists Describe Detector Goals for Electron-Ion Collider (EIC)” 

    From DOE’s Brookhaven National Laboratory(US)

    March 16, 2021

    kmcnulty@bnl.gov
    Karen McNulty Walsh

    (631) 344-8350

    Peter Genzer
    genzer@bnl.gov
    (631) 344-3174

    International community of EIC scientists publishes “yellow report” laying out physics case, detector requirements, and evolving detector concepts for future nuclear physics facility.

    1
    The EIC Yellow Report is published in three volumes: an executive summary, a detailed description of the physics, and a discussion of detector concepts. Credit: Yulia Furletova and Shannon West for the EIC User Group.

    What do you need to study the fine details of the building blocks of matter? A new kind of particle accelerator called an Electron-Ion Collider (EIC) [below] —planned to be built in the United States over the next decade—and a state-of-the-art detector to capture the action when electrons and ions collide. As part of the plan to build the EIC, an international team of more than 400 scientists representing 151 research institutions around the world prepared a detailed report of the detector components they believe are needed to meet the scientific goals of this new facility.

    The report, titled Science Requirements and Detector Concepts for the Electron-Ion Collider: EIC Yellow Report, was posted online on March 8, 2021.

    “The enormous effort that led to this document aimed to provide the basis for further development of concepts for experimental equipment best suited for the science needs,” said Thomas Ullrich, a nuclear physicist involved in compiling the report and representative of the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory in the international EIC User Group (EICUG). “It is timely, as the formation of EIC collaborations is beginning. This is a big step toward the realization of a general-purpose detector that will form the basis for a world-class experimental program that aims to increase our understanding of the fundamental structure of all visible matter.”

    The EIC is in the early stage of development with the DOE Office of Science’s Nuclear Physics Program. It is slated to be built at Brookhaven Lab(US) in partnership with physicists from DOE’s Thomas Jefferson National Accelerator Facility(US) and scientists throughout the worldwide nuclear physics research community, with funding from the DOE Office of Science and other national and international partners.

    Jefferson Lab EICUG representative Rolf Ent said, “The Yellow Report represents a year-long superb effort of the EIC community. This community spans the world, with crucial contributions coming from many scientists in many countries, underscoring that we all work together as one community toward shared science goals.”

    The EIC will be a powerful new facility for nuclear physics research that will collide high-energy electron beams with high-energy proton and ion beams (nuclei of atoms that have been stripped of their electrons). The collisions will give scientists access to the dynamic internal structure of protons, neutrons, and nuclei in a regime where their structure is dominated by gluons. Studying gluons—the force-carrier particles that hold together the internal building blocks of protons and neutrons (known as quarks)—will help scientists understand how quarks and gluons build up the mass and structure of the visible matter in our universe. In addition, because the EIC’s beams will be polarized—meaning the “spin” of the colliding particles can be aligned and controlled in desired ways—scientists will be able to explore how quarks and gluons contribute to the spin of fundamental particles.

    “We may know more about some distant stars and galaxies than we do about the inner-workings of the building blocks of the matter right around us,” said Olga Evdokimov of the University of Illinois-Chicago(US), who is one of the EIC Physics Working Group conveners and chair of the EICUG Institutional Board. “The developments of the Yellow Report bring us one step closer to realizing a unique facility in the world for exploring how the tiny, nearly massless quarks and massless gluons hidden within protons and neutrons give mass to these much heavier particles that make up all visible matter in the Universe.”

    “In addition, the technological innovations in detector design and computing streaming from this project will undoubtedly benefit other sciences and have a broad impact on society through workforce development across the science, technology, engineering, and mathematics (STEM) fields,” she said.

    The EIC Yellow Report lays out the facility’s scientific goals in great detail, describes the specific detector requirements needed to address those goals, and presents the evolving detector concepts being explored to realize the EIC’s experimental program.

    The report is the culmination of a series of studies commissioned and organized by the EIC User Group. But it is not intended to be a final plan. Rather, the EICUG sees the report as the basis for further development of concepts for experimental equipment best suited for the EIC’s science needs.

    “In the long, one-year effort towards the completion of the Yellow Report, we have formed an international collaborative community. Now it is time to strengthen the collaboration,” said Silvia Dalla Torre, an EICUG Steering Committee member from National Institute for Nuclear Physics[Institutio Nzaionale di Fisica Nucleare](IT). “We look forward to the next exciting phase, namely the common effort of design and construction of one or possibly two detectors that will make possible accessing the physics goals of the EIC.”

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    One of ten national laboratories overseen and primarily funded by the DOE(US) Office of Science, DOE’s Brookhaven National Laboratory(US) conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University (US) the largest academic user of Laboratory facilities, and Battelle(US), a nonprofit, applied science and technology organization.

    Research at BNL specializes in nuclear and high energy physics, energy science and technology, environmental and bioscience, nanoscience and national security. The 5,300 acre campus contains several large research facilities, including the Relativistic Heavy Ion Collider [below] and National Synchrotron Light Source II [below]. Seven Nobel prizes have been awarded for work conducted at Brookhaven lab.

    BNL is staffed by approximately 2,750 scientists, engineers, technicians, and support personnel, and hosts 4,000 guest investigators every year. The laboratory has its own police station, fire department, and ZIP code (11973). In total, the lab spans a 5,265-acre (21 km^2) area that is mostly coterminous with the hamlet of Upton, New York. BNL is served by a rail spur operated as-needed by the New York and Atlantic Railway. Co-located with the laboratory is the Upton, New York, forecast office of the National Weather Service.

    Major programs

    Although originally conceived as a nuclear research facility, Brookhaven Lab’s mission has greatly expanded. Its foci are now:

    Nuclear and high-energy physics
    Physics and chemistry of materials
    Environmental and climate research
    Nanomaterials
    Energy research
    Nonproliferation
    Structural biology
    Accelerator physics

    Operation

    DOE’s Brookhaven National Lab(US) was originally owned by the Atomic Energy Commission(US) and is now owned by that agency’s successor, the United States Department of Energy (DOE). DOE subcontracts the research and operation to universities and research organizations. It is currently operated by Brookhaven Science Associates LLC, which is an equal partnership of Stony Brook University(US) and Battelle Memorial Institute(US). From 1947 to 1998, it was operated by Associated Universities, Inc. (AUI), but AUI lost its contract in the wake of two incidents: a 1994 fire at the facility’s high-beam flux reactor that exposed several workers to radiation and reports in 1997 of a tritium leak into the groundwater of the Long Island Central Pine Barrens on which the facility sits.

    Foundations

    Following World War II, the US Atomic Energy Commission was created to support government-sponsored peacetime research on atomic energy. The effort to build a nuclear reactor in the American northeast was fostered largely by physicists Isidor Isaac Rabi and Norman Foster Ramsey Jr., who during the war witnessed many of their colleagues at Columbia University leave for new remote research sites following the departure of the Manhattan Project from its campus. Their effort to house this reactor near New York City was rivalled by a similar effort at the Massachusetts Institute of Technology(US) to have a facility near Boston, Massachusettes(US). Involvement was quickly solicited from representatives of northeastern universities to the south and west of New York City such that this city would be at their geographic center. In March 1946 a nonprofit corporation was established that consisted of representatives from nine major research universities — Columbia(US), Cornell(US), Harvard(US), Johns Hopkins(US), MIT, Princeton University(US), University of Pennsylvania(US), University of Rochester(US), and Yale University(US).

    Out of 17 considered sites in the Boston-Washington corridor, Camp Upton on Long Island was eventually chosen as the most suitable in consideration of space, transportation, and availability. The camp had been a training center from the US Army during both World War I and World War II. After the latter war, Camp Upton was deemed no longer necessary and became available for reuse. A plan was conceived to convert the military camp into a research facility.

    On March 21, 1947, the Camp Upton site was officially transferred from the U.S. War Department to the new U.S. Atomic Energy Commission (AEC), predecessor to the U.S. Department of Energy (DOE).

    Research and facilities

    Reactor history

    In 1947 construction began on the first nuclear reactor at Brookhaven, the Brookhaven Graphite Research Reactor. This reactor, which opened in 1950, was the first reactor to be constructed in the United States after World War II. The High Flux Beam Reactor operated from 1965 to 1999. In 1959 Brookhaven built the first US reactor specifically tailored to medical research, the Brookhaven Medical Research Reactor, which operated until 2000.

    Accelerator history

    In 1952 Brookhaven began using its first particle accelerator, the Cosmotron. At the time the Cosmotron was the world’s highest energy accelerator, being the first to impart more than 1 GeV of energy to a particle.

    BNL Cosmotron 1952-1966

    The Cosmotron was retired in 1966, after it was superseded in 1960 by the new Alternating Gradient Synchrotron (AGS).

    BNL Alternating Gradient Synchrotron (AGS)

    The AGS was used in research that resulted in 3 Nobel prizes, including the discovery of the muon neutrino, the charm quark, and CP violation.

    In 1970 in BNL started the ISABELLE project to develop and build two proton intersecting storage rings.

    The groundbreaking for the project was in October 1978. In 1981, with the tunnel for the accelerator already excavated, problems with the superconducting magnets needed for the ISABELLE accelerator brought the project to a halt, and the project was eventually cancelled in 1983.

    The National Synchrotron Light Source operated from 1982 to 2014 and was involved with two Nobel Prize-winning discoveries. It has since been replaced by the National Synchrotron Light Source II [below].

    BNL NSLS.

    After ISABELLE’S cancellation, physicist at BNL proposed that the excavated tunnel and parts of the magnet assembly be used in another accelerator. In 1984 the first proposal for the accelerator now known as the Relativistic Heavy Ion Collider (RHIC)[below] was put forward. The construction got funded in 1991 and RHIC has been operational since 2000. One of the world’s only two operating heavy-ion colliders, RHIC is as of 2010 the second-highest-energy collider after the Large Hadron Collider(CH). RHIC is housed in a tunnel 2.4 miles (3.9 km) long and is visible from space.

    On January 9, 2020, It was announced by Paul Dabbar, undersecretary of the US Department of Energy Office of Science, that the BNL eRHIC design has been selected over the conceptual design put forward by DOE’s Thomas Jefferson National Accelerator Facility [Jlab] as the future Electron–ion collider (EIC) in the United States.

    Electron-Ion Collider (EIC) at BNL, to be built inside the tunnel that currently houses the RHIC.

    In addition to the site selection, it was announced that the BNL EIC had acquired CD-0 (mission need) from the Department of Energy. BNL’s eRHIC design proposes upgrading the existing Relativistic Heavy Ion Collider, which collides beams light to heavy ions including polarized protons, with a polarized electron facility, to be housed in the same tunnel.

    Other discoveries

    In 1958, Brookhaven scientists created one of the world’s first video games, Tennis for Two. In 1968 Brookhaven scientists patented Maglev, a transportation technology that utilizes magnetic levitation.

    Major facilities

    Relativistic Heavy Ion Collider (RHIC), which was designed to research quark–gluon plasma[16] and the sources of proton spin. Until 2009 it was the world’s most powerful heavy ion collider. It is the only collider of spin-polarized protons.
    Center for Functional Nanomaterials (CFN), used for the study of nanoscale materials.
    National Synchrotron Light Source II (NSLS-II), Brookhaven’s newest user facility, opened in 2015 to replace the National Synchrotron Light Source (NSLS), which had operated for 30 years.[19] NSLS was involved in the work that won the 2003 and 2009 Nobel Prize in Chemistry.
    Alternating Gradient Synchrotron, a particle accelerator that was used in three of the lab’s Nobel prizes.
    Accelerator Test Facility, generates, accelerates and monitors particle beams.
    Tandem Van de Graaff, once the world’s largest electrostatic accelerator.
    Computational Science resources, including access to a massively parallel Blue Gene series supercomputer that is among the fastest in the world for scientific research, run jointly by Brookhaven National Laboratory and Stony Brook University.
    Interdisciplinary Science Building, with unique laboratories for studying high-temperature superconductors and other materials important for addressing energy challenges.
    NASA Space Radiation Laboratory, where scientists use beams of ions to simulate cosmic rays and assess the risks of space radiation to human space travelers and equipment.

    Off-site contributions

    It is a contributing partner to ATLAS experiment, one of the four detectors located at the Large Hadron Collider (LHC).

    CERN map

    Iconic view of the CERN (CH) ATLAS detector.

    It is currently operating at CERN near Geneva, Switzerland.

    Brookhaven was also responsible for the design of the SNS accumulator ring in partnership with Spallation Neutron Source at DOE’s Oak Ridge National Laboratory, Tennessee.

    ORNL Spallation Neutron Source annotated.

    Brookhaven plays a role in a range of neutrino research projects around the world, including the Daya Bay Reactor Neutrino Experiment in China and the Deep Underground Neutrino Experiment at DOE’s Fermi National Accelerator Laboratory(US).

    Daya Bay, nuclear power plant, approximately 52 kilometers northeast of Hong Kong and 45 kilometers east of Shenzhen, China

    FNAL LBNF/DUNE from FNAL to SURF, Lead, South Dakota, USA.

    Brookhaven Campus.

    BNL Center for Functional Nanomaterials.

    BNL NSLS-II.

    BNL NSLS II.

    BNL RHIC Campus.

    BNL/RHIC Star Detector.

    BNL/RHIC Phenix.

     
  • richardmitnick 11:38 am on March 12, 2021 Permalink | Reply
    Tags: "Searching for Signs of 'Glueballs' in Proton-Proton Smashups", , An experiment at the Relativistic Heavy Ion Collider [RHIC] searched for evidence by looking for decay products of glueballs., , BNL EIC:Electron-Ion Collider, DOE’s Brookhaven National Laboratory(US), If scientists find clear evidence that glueballs exist it would confirm a prediction of the theory describing the strong nuclear force., In proton collisions where the two scattered protons are intact after the collision there is an increased chance that two gluons might have combined to form a glueball.,   

    From DOE’s Brookhaven National Laboratory(US): “Searching for Signs of ‘Glueballs’ in Proton-Proton Smashups” 

    From DOE’s Brookhaven National Laboratory(US)

    March 9, 2021

    Contacts

    Wlodek Guryn
    Brookhaven National Laboratory
    guryn@bnl.gov

    Mariusz Przybycien
    AGH University of Science and Technology
    mariusz.przybycien@agh.edu.pl

    Gluons-the particles that bind quarks-may also bind to one another. Scientists are searching for evidence of these globs of pure “glue”.

    1
    In particles made of two and three quarks (mesons and baryons), quarks are held together by gluons, carriers of the strong force (shown as springs). Theory also predicts “glueballs,” particles made of gluons and quark-antiquark pairs (shown as dots). An experiment at the Relativistic Heavy Ion Collider [RHIC] searched for evidence by looking for decay products of glueballs. Credit: University of Glasgow(SC).

    The Science

    The subatomic particles that make up the universe interact in complex ways. In mesons and baryons, quarks and antiquarks are bound together by gluons, the carriers of the nuclear strong force. In the Standard Model of Particle Physics, gluons can also interact with each other. This means in principle that the universe should contain objects composed only of gluons in a sea of quark-antiquark pairs. However, scientists’ experiments have never definitively confirmed these hypothetical objects, called “glueballs.” Physicists searched for signs using the Relativistic Heavy Ion Collider (RHIC) [below]—a U.S. Department of Energy (DOE) Office of Science user facility for nuclear physics research at DOE’s Brookhaven National Laboratory. Because glueballs decay very quickly, the scientists used the Solenoidal Tracker at RHIC (the STAR detector [below]) to look for the decay products these glueballs are expected to transform into after their very short lifetime.

    The Impact

    If scientists find clear evidence that glueballs exist it would confirm a prediction of the theory describing the strong nuclear force. This force binds the quarks inside protons and neutrons and also holds together the nuclei of atoms that make up the visible matter in our universe. Finding clear evidence that glueballs do not exist would mean scientists need to revise the theory. Also, developing the ability to track the decay of possible glueballs lays the groundwork for using this technique at a future Electron-Ion Collider (EIC).

    Electron-Ion Collider (EIC) at DOE’s Brookhaven National Laboratory, to be built inside the tunnel that currently houses the Relativistic Heavy Ion Collider [RHIC].

    This EIC will allow physicists to explore the strong force with precision experiments to reveal how gluons establish the properties of the building blocks of matter.

    Summary

    In proton collisions where the two scattered protons are intact after the collision there is an increased chance that two gluons might have combined to form a glueball. Scientists used the STAR detector and other methods to identify collisions where intact protons continued on their forward journey and emerged at small angles on each side of the detector, while simultaneously searching for signs of the decay particles predicted for glueballs. Using statistical techniques and particle identification methods to analyze combinations of particles from millions of collisions, the scientists generated a type of “spectrum” of certain properties of the detected particles to see if it would match the spectrum expected from a decaying glueball. The approach is similar to using a light spectrum to determine a material’s chemical composition by comparing an observed spectrum with the known spectrum generated by each of the elements. The spectrum calculated from the RHIC observations revealed only hints of the glueballs’ signature, so the search will continue. However, the findings do show that the technique—measuring forward-moving protons and decay products—works and can be used to examine additional RHIC data and implemented at the EIC.

    Science paper:
    Measurement of the central exclusive production of charged particle pairs in proton-proton collisions at s√
    = 200 GeV with the STAR detector at RHIC

    Journal of High Energy Physics

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    One of ten national laboratories overseen and primarily funded by the DOE(US) Office of Science, DOE’s Brookhaven National Laboratory(US) conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University(US)the largest academic user of Laboratory facilities, and Battelle(US), a nonprofit, applied science and technology organization.

    Research at BNL specializes in nuclear and high energy physics, energy science and technology, environmental and bioscience, nanoscience and national security. The 5,300 acre campus contains several large research facilities, including the Relativistic Heavy Ion Collider [below] and National Synchrotron Light Source II [below]. Seven Nobel prizes have been awarded for work conducted at Brookhaven lab.

    BNL is staffed by approximately 2,750 scientists, engineers, technicians, and support personnel, and hosts 4,000 guest investigators every year. The laboratory has its own police station, fire department, and ZIP code (11973). In total, the lab spans a 5,265-acre (21 km^2) area that is mostly coterminous with the hamlet of Upton, New York. BNL is served by a rail spur operated as-needed by the New York and Atlantic Railway. Co-located with the laboratory is the Upton, New York, forecast office of the National Weather Service.

    Major programs

    Although originally conceived as a nuclear research facility, Brookhaven Lab’s mission has greatly expanded. Its foci are now:

    Nuclear and high-energy physics
    Physics and chemistry of materials
    Environmental and climate research
    Nanomaterials
    Energy research
    Nonproliferation
    Structural biology
    Accelerator physics

    Operation

    Brookhaven National Lab was originally owned by the Atomic Energy Commission(US) and is now owned by that agency’s successor, the United States Department of Energy (DOE). DOE subcontracts the research and operation to universities and research organizations. It is currently operated by Brookhaven Science Associates LLC, which is an equal partnership of Stony Brook University(US) and Battelle Memorial Institute(US). From 1947 to 1998, it was operated by Associated Universities, Inc. (AUI), but AUI lost its contract in the wake of two incidents: a 1994 fire at the facility’s high-beam flux reactor that exposed several workers to radiation and reports in 1997 of a tritium leak into the groundwater of the Long Island Central Pine Barrens on which the facility sits.

    Foundations

    Following World War II, the US Atomic Energy Commission was created to support government-sponsored peacetime research on atomic energy. The effort to build a nuclear reactor in the American northeast was fostered largely by physicists Isidor Isaac Rabi and Norman Foster Ramsey Jr., who during the war witnessed many of their colleagues at Columbia University leave for new remote research sites following the departure of the Manhattan Project from its campus. Their effort to house this reactor near New York City was rivalled by a similar effort at the Massachusetts Institute of Technology(US) to have a facility near Boston, Massachusettes(US). Involvement was quickly solicited from representatives of northeastern universities to the south and west of New York City such that this city would be at their geographic center. In March 1946 a nonprofit corporation was established that consisted of representatives from nine major research universities — Columbia(US), Cornell(US), Harvard(US), Johns Hopkins(US), MIT, Princeton University(US), University of Pennsylvania(US), University of Rochester(US), and Yale University(US).

    Out of 17 considered sites in the Boston-Washington corridor, Camp Upton on Long Island was eventually chosen as the most suitable in consideration of space, transportation, and availability. The camp had been a training center from the US Army during both World War I and World War II. After the latter war, Camp Upton was deemed no longer necessary and became available for reuse. A plan was conceived to convert the military camp into a research facility.

    On March 21, 1947, the Camp Upton site was officially transferred from the U.S. War Department to the new U.S. Atomic Energy Commission (AEC), predecessor to the U.S. Department of Energy (DOE).

    Research and facilities

    Reactor history

    In 1947 construction began on the first nuclear reactor at Brookhaven, the Brookhaven Graphite Research Reactor. This reactor, which opened in 1950, was the first reactor to be constructed in the United States after World War II. The High Flux Beam Reactor operated from 1965 to 1999. In 1959 Brookhaven built the first US reactor specifically tailored to medical research, the Brookhaven Medical Research Reactor, which operated until 2000.

    Accelerator history

    In 1952 Brookhaven began using its first particle accelerator, the Cosmotron. At the time the Cosmotron was the world’s highest energy accelerator, being the first to impart more than 1 GeV of energy to a particle.

    BNL Cosmotron 1952-1966

    The Cosmotron was retired in 1966, after it was superseded in 1960 by the new Alternating Gradient Synchrotron (AGS).

    BNL Alternating Gradient Synchrotron (AGS)

    The AGS was used in research that resulted in 3 Nobel prizes, including the discovery of the muon neutrino, the charm quark, and CP violation.

    In 1970 in BNL started the ISABELLE project to develop and build two proton intersecting storage rings.

    The groundbreaking for the project was in October 1978. In 1981, with the tunnel for the accelerator already excavated, problems with the superconducting magnets needed for the ISABELLE accelerator brought the project to a halt, and the project was eventually cancelled in 1983.

    The National Synchrotron Light Source operated from 1982 to 2014 and was involved with two Nobel Prize-winning discoveries. It has since been replaced by the National Synchrotron Light Source II [below].

    BNL NSLS.

    After ISABELLE’S cancellation, physicist at BNL proposed that the excavated tunnel and parts of the magnet assembly be used in another accelerator. In 1984 the first proposal for the accelerator now known as the Relativistic Heavy Ion Collider (RHIC)[below] was put forward. The construction got funded in 1991 and RHIC has been operational since 2000. One of the world’s only two operating heavy-ion colliders, RHIC is as of 2010 the second-highest-energy collider after the Large Hadron Collider(CH). RHIC is housed in a tunnel 2.4 miles (3.9 km) long and is visible from space.

    On January 9, 2020, It was announced by Paul Dabbar, undersecretary of the US Department of Energy Office of Science, that the BNL eRHIC design has been selected over the conceptual design put forward by DOE’s Thomas Jefferson National Accelerator Facility [Jlab] as the future Electron–ion collider (EIC) in the United States.

    Electron-Ion Collider (EIC) at BNL, to be built inside the tunnel that currently houses the RHIC.

    In addition to the site selection, it was announced that the BNL EIC had acquired CD-0 (mission need) from the Department of Energy. BNL’s eRHIC design proposes upgrading the existing Relativistic Heavy Ion Collider, which collides beams light to heavy ions including polarized protons, with a polarized electron facility, to be housed in the same tunnel.

    Other discoveries

    In 1958, Brookhaven scientists created one of the world’s first video games, Tennis for Two. In 1968 Brookhaven scientists patented Maglev, a transportation technology that utilizes magnetic levitation.

    Major facilities

    Relativistic Heavy Ion Collider (RHIC), which was designed to research quark–gluon plasma[16] and the sources of proton spin. Until 2009 it was the world’s most powerful heavy ion collider. It is the only collider of spin-polarized protons.
    Center for Functional Nanomaterials (CFN), used for the study of nanoscale materials.
    National Synchrotron Light Source II (NSLS-II), Brookhaven’s newest user facility, opened in 2015 to replace the National Synchrotron Light Source (NSLS), which had operated for 30 years.[19] NSLS was involved in the work that won the 2003 and 2009 Nobel Prize in Chemistry.
    Alternating Gradient Synchrotron, a particle accelerator that was used in three of the lab’s Nobel prizes.
    Accelerator Test Facility, generates, accelerates and monitors particle beams.
    Tandem Van de Graaff, once the world’s largest electrostatic accelerator.
    Computational Science resources, including access to a massively parallel Blue Gene series supercomputer that is among the fastest in the world for scientific research, run jointly by Brookhaven National Laboratory and Stony Brook University.
    Interdisciplinary Science Building, with unique laboratories for studying high-temperature superconductors and other materials important for addressing energy challenges.
    NASA Space Radiation Laboratory, where scientists use beams of ions to simulate cosmic rays and assess the risks of space radiation to human space travelers and equipment.

    Off-site contributions

    It is a contributing partner to ATLAS experiment, one of the four detectors located at the Large Hadron Collider (LHC).

    CERN map

    Iconic view of the CERN (CH) ATLAS detector.

    It is currently operating at CERN near Geneva, Switzerland.

    Brookhaven was also responsible for the design of the SNS accumulator ring in partnership with Spallation Neutron Source at DOE’s Oak Ridge National Laboratory, Tennessee.

    ORNL Spallation Neutron Source annotated.

    Brookhaven plays a role in a range of neutrino research projects around the world, including the Daya Bay Reactor Neutrino Experiment in China and the Deep Underground Neutrino Experiment at DOE’s Fermi National Accelerator Laboratory(US).

    Daya Bay, nuclear power plant, approximately 52 kilometers northeast of Hong Kong and 45 kilometers east of Shenzhen, China

    FNAL LBNF/DUNE from FNAL to SURF, Lead, South Dakota, USA.

    Brookhaven Campus.

    BNL Center for Functional Nanomaterials.

    BNL NSLS-II.

    BNL NSLS II.

    BNL RHIC Campus.

    BNL/RHIC Star Detector.

    BNL/RHIC Phenix.

     
  • richardmitnick 3:56 pm on March 5, 2021 Permalink | Reply
    Tags: "Tantalizing Signs of Phase-change ‘Turbulence’ in RHIC Collisions", , , Despite the tantalizing hints the STAR scientists acknowledge that the range of uncertainty in their measurements is still large., DOE’s Brookhaven National Laboratory(US), Net baryon density, , , , , STAR physicists took advantage of the incredible versatility of RHIC to collide gold ions (the nuclei of gold atoms) across a wide range of energies., Strictly speaking if the scientists don’t identify either the phase boundary or the critical point they really can’t put this [QGP phase] into the textbooks and say that there is a new state of ma, Tantalizing signs of a critical point—a change in the way that quarks and gluons-the building blocks of protons and neutrons-transform from one phase to another., The work is also a true collaboration of the experimentalists with nuclear theorists around the world and the accelerator physicists at RHIC., When there is a change from high energy to low energy there is an increase in the net baryon density and the structure of matter may change going through the phase transition area.   

    From DOE’s Brookhaven National Laboratory(US): “Tantalizing Signs of Phase-change ‘Turbulence’ in RHIC Collisions” 

    From DOE’s Brookhaven National Laboratory(US)

    March 5, 2021
    Karen McNulty Walsh
    Peter Genzer

    Fluctuations in net proton production hint at a possible ‘critical point’ marking a change in the way nuclear matter transforms from one phase to another.

    1
    The STAR detector at the U.S. Department of Energy’s Brookhaven National Laboratory.

    Physicists studying collisions of gold ions at the Relativistic Heavy Ion Collider (RHIC), a U.S. Department of Energy Office of Science user facility for nuclear physics research at DOE’s Brookhaven National Laboratory, are embarking on a journey through the phases of nuclear matter—the stuff that makes up the nuclei of all the visible matter in our universe. A new analysis of collisions conducted at different energies shows tantalizing signs of a critical point—a change in the way that quarks and gluons-the building blocks of protons and neutrons-transform from one phase to another. The findings, just published by RHIC’s STAR Collaboration in the journal Physical Review Letters, will help physicists map out details of these nuclear phase changes to better understand the evolution of the universe and the conditions in the cores of neutron stars.

    “If we are able to discover this critical point, then our map of nuclear phases—the nuclear phase diagram—may find a place in the textbooks, alongside that of water,” said Bedanga Mohanty of India’s National Institute of Science and Research, one of hundreds of physicists collaborating on research at RHIC using the sophisticated STAR detector.

    As Mohanty noted, studying nuclear phases is somewhat like learning about the solid, liquid, and gaseous forms of water, and mapping out how the transitions take place depending on conditions like temperature and pressure. But with nuclear matter, you can’t just set a pot on the stove and watch it boil. You need powerful particle accelerators like RHIC to turn up the heat.

    2
    As physicists turned the collision energy down at RHIC, they expected to see large event-by-event fluctuations in certain measurements such as net proton production—an effect that’s similar to the turbulence an airplane experiences when entering a bank of clouds—as evidence of a “critical point” in the nuclear phase transition. Higher level statistical analyses of the data, including the skew (kurtosis), revealed tantalizing hints of such fluctuations.

    RHIC’s highest collision energies “melt” ordinary nuclear matter (atomic nuclei made of protons and neutrons) to create an exotic phase called a quark-gluon plasma (QGP). Scientists believe the entire universe existed as QGP a fraction of a second after the Big Bang—before it cooled and the quarks bound together (glued by gluons) to form protons, neutrons, and eventually, atomic nuclei. But the tiny drops of QGP created at RHIC measure a mere 10^-13 centimeters across (that’s 0.0000000000001 cm) and they last for only 10^-23 seconds! That makes it incredibly challenging to map out the melting and freezing of the matter that makes up our world.

    “Strictly speaking if we don’t identify either the phase boundary or the critical point we really can’t put this [QGP phase] into the textbooks and say that we have a new state of matter,” said Nu Xu, a STAR physicist at DOE’s Lawrence Berkeley National Laboratory.

    Tracking phase transitions

    To track the transitions, STAR physicists took advantage of the incredible versatility of RHIC to collide gold ions (the nuclei of gold atoms) across a wide range of energies.

    2
    Mapping nuclear phase changes is like studying how water changes under different conditions of temperature and pressure (net baryon density for nuclear matter). RHIC’s collisions “melt” protons and neutrons to create quark-gluon plasma (QGP). STAR physicists are exploring collisions at different energies, turning the “knobs” of temperature and baryon density, to look for signs of a “critical point.”

    “RHIC is the only facility that can do this, providing beams from 200 billion electron volts (GeV) all the way down to 3 GeV. Nobody can dream of such an excellent machine,” Xu said.

    The changes in energy turn the collision temperature up and down and also vary a quantity known as net baryon density that is somewhat analogous to pressure. Looking at data collected during the first phase of RHIC’s “beam energy scan” from 2010 to 2017, STAR physicists tracked particles streaming out at each collision energy. They performed a detailed statistical analysis of the net number of protons produced. A number of theorists had predicted that this quantity would show large event-by-event fluctuations as the critical point is approached.

    The reason for the expected fluctuations comes from a theoretical understanding of the force that governs quarks and gluons. That theory, known as quantum chromodynamics, suggests that the transition from normal nuclear matter (“hadronic” protons and neutrons) to QGP can take place in two different ways. At high temperatures, where protons and anti-protons are produced in pairs and the net baryon density is close to zero, physicists have evidence of a smooth crossover between the phases. It’s as if protons gradually melt to form QGP, like butter gradually melting on a counter on a warm day. But at lower energies, they expect what’s called a first-order phase transition—an abrupt change like water boiling at a set temperature as individual molecules escape the pot to become steam. Nuclear theorists predict that in the QGP-to-hadronic-matter phase transition, net proton production should vary dramatically as collisions approach this switchover point.

    “At high energy, there is only one phase. The system is more or less invariant, normal,” Xu said. “But when we change from high energy to low energy you also increase the net baryon density and the structure of matter may change as you are going through the phase transition area.

    “It’s just like when you ride an airplane and you get into turbulence,” he added. “You see the fluctuation—boom, boom, boom. Then, when you pass the turbulence—the phase of structural changes—you are back to normal into the one-phase structure.”

    In the RHIC collision data, the signs of this turbulence are not as apparent as food and drinks bouncing off tray tables in an airplane. STAR physicists had to perform what’s known as “higher order correlation function” statistical analysis of the distributions of particles—looking for more than just the mean and width of the curve representing the data to things like how asymmetrical and skewed that distribution is.

    The oscillations they see in these higher orders, particularly the skew (or kurtosis), are reminiscent of another famous phase change observed when transparent liquid carbon dioxide suddenly becomes cloudy when heated, the scientists say. This “critical opalescence” comes from dramatic fluctuations in the density of the CO2—variations in how tightly packed the molecules are.

    “In our data, the oscillations signify that something interesting is happening, like the opalescence,” Mohanty said.

    Yet despite the tantalizing hints the STAR scientists acknowledge that the range of uncertainty in their measurements is still large. The team hopes to narrow that uncertainty to nail their critical point discovery by analyzing a second set of measurements made from many more collisions during phase II of RHIC’s beam energy scan, from 2019 through 2021.

    The entire STAR collaboration was involved in the analysis, Xu notes, with a particular group of physicists—including Xiaofeng Luo (and his student, Yu Zhang), Ashish Pandav, and Toshihiro Nonaka, from China, India, and Japan, respectively—meeting weekly with the U.S. scientists (over many time zones and virtual networks) to discuss and refine the results. The work is also a true collaboration of the experimentalists with nuclear theorists around the world and the accelerator physicists at RHIC. The latter group, in Brookhaven Lab’s Collider-Accelerator Department, devised ways to run RHIC far below its design energy while also maximizing collision rates to enable the collection of the necessary data at low collision energies.

    “We are exploring uncharted territory,” Xu said. “This has never been done before. We made lots of efforts to control the environment and make corrections, and we are eagerly awaiting the next round of higher statistical data,” he said.

    This study was supported by the DOE Office of Science, the U.S. National Science Foundation, and a wide range of international funding agencies listed in the paper. RHIC operations are funded by the DOE Office of Science. Data analysis was performed using computing resources at the RHIC and ATLAS Computing Facility (RACF) at Brookhaven Lab, the National Energy Research Scientific Computing Center (NERSC) at Lawrence Berkeley National Laboratory, and via the Open Science Grid consortium.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    One of ten national laboratories overseen and primarily funded by the DOE(US) Office of Science, DOE’s Brookhaven National Laboratory(US) conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University(US), the largest academic user of Laboratory facilities, and Battelle(US), a nonprofit, applied science and technology organization.

    Research at BNL specializes in nuclear and high energy physics, energy science and technology, environmental and bioscience, nanoscience and national security. The 5,300 acre campus contains several large research facilities, including the Relativistic Heavy Ion Collider [below] and National Synchrotron Light Source II [below]. Seven Nobel prizes have been awarded for work conducted at Brookhaven lab.

    BNL is staffed by approximately 2,750 scientists, engineers, technicians, and support personnel, and hosts 4,000 guest investigators every year. The laboratory has its own police station, fire department, and ZIP code (11973). In total, the lab spans a 5,265-acre (21 km^2) area that is mostly coterminous with the hamlet of Upton, New York. BNL is served by a rail spur operated as-needed by the New York and Atlantic Railway. Co-located with the laboratory is the Upton, New York, forecast office of the National Weather Service.

    Major programs

    Although originally conceived as a nuclear research facility, Brookhaven Lab’s mission has greatly expanded. Its foci are now:

    Nuclear and high-energy physics
    Physics and chemistry of materials
    Environmental and climate research
    Nanomaterials
    Energy research
    Nonproliferation
    Structural biology
    Accelerator physics

    Operation

    Brookhaven National Lab was originally owned by the Atomic Energy Commission(US) and is now owned by that agency’s successor, the United States Department of Energy (DOE). DOE subcontracts the research and operation to universities and research organizations. It is currently operated by Brookhaven Science Associates LLC, which is an equal partnership of Stony Brook University(US) and Battelle Memorial Institute(US). From 1947 to 1998, it was operated by Associated Universities, Inc. (AUI), but AUI lost its contract in the wake of two incidents: a 1994 fire at the facility’s high-beam flux reactor that exposed several workers to radiation and reports in 1997 of a tritium leak into the groundwater of the Long Island Central Pine Barrens on which the facility sits.

    Foundations

    Following World War II, the US Atomic Energy Commission was created to support government-sponsored peacetime research on atomic energy. The effort to build a nuclear reactor in the American northeast was fostered largely by physicists Isidor Isaac Rabi and Norman Foster Ramsey Jr., who during the war witnessed many of their colleagues at Columbia University leave for new remote research sites following the departure of the Manhattan Project from its campus. Their effort to house this reactor near New York City was rivalled by a similar effort at the Massachusetts Institute of Technology(US) to have a facility near Boston, Massachusettes(US). Involvement was quickly solicited from representatives of northeastern universities to the south and west of New York City such that this city would be at their geographic center. In March 1946 a nonprofit corporation was established that consisted of representatives from nine major research universities — Columbia(US), Cornell(US), Harvard(US), Johns Hopkins(US), MIT, Princeton University(US), University of Pennsylvania(US), University of Rochester(US), and Yale University(US).

    Out of 17 considered sites in the Boston-Washington corridor, Camp Upton on Long Island was eventually chosen as the most suitable in consideration of space, transportation, and availability. The camp had been a training center from the US Army during both World War I and World War II. After the latter war, Camp Upton was deemed no longer necessary and became available for reuse. A plan was conceived to convert the military camp into a research facility.

    On March 21, 1947, the Camp Upton site was officially transferred from the U.S. War Department to the new U.S. Atomic Energy Commission (AEC), predecessor to the U.S. Department of Energy (DOE).

    Research and facilities

    Reactor history

    In 1947 construction began on the first nuclear reactor at Brookhaven, the Brookhaven Graphite Research Reactor. This reactor, which opened in 1950, was the first reactor to be constructed in the United States after World War II. The High Flux Beam Reactor operated from 1965 to 1999. In 1959 Brookhaven built the first US reactor specifically tailored to medical research, the Brookhaven Medical Research Reactor, which operated until 2000.

    Accelerator history

    In 1952 Brookhaven began using its first particle accelerator, the Cosmotron. At the time the Cosmotron was the world’s highest energy accelerator, being the first to impart more than 1 GeV of energy to a particle.

    BNL Cosmotron 1952-1966

    The Cosmotron was retired in 1966, after it was superseded in 1960 by the new Alternating Gradient Synchrotron (AGS).

    BNL Alternating Gradient Synchrotron (AGS)

    The AGS was used in research that resulted in 3 Nobel prizes, including the discovery of the muon neutrino, the charm quark, and CP violation.

    In 1970 in BNL started the ISABELLE project to develop and build two proton intersecting storage rings.

    The groundbreaking for the project was in October 1978. In 1981, with the tunnel for the accelerator already excavated, problems with the superconducting magnets needed for the ISABELLE accelerator brought the project to a halt, and the project was eventually cancelled in 1983.

    The National Synchrotron Light Source operated from 1982 to 2014 and was involved with two Nobel Prize-winning discoveries. It has since been replaced by the National Synchrotron Light Source II [below].

    BNL NSLS.

    After ISABELLE’S cancellation, physicist at BNL proposed that the excavated tunnel and parts of the magnet assembly be used in another accelerator. In 1984 the first proposal for the accelerator now known as the Relativistic Heavy Ion Collider (RHIC)[below] was put forward. The construction got funded in 1991 and RHIC has been operational since 2000. One of the world’s only two operating heavy-ion colliders, RHIC is as of 2010 the second-highest-energy collider after the Large Hadron Collider(CH). RHIC is housed in a tunnel 2.4 miles (3.9 km) long and is visible from space.

    On January 9, 2020, It was announced by Paul Dabbar, undersecretary of the US Department of Energy Office of Science, that the BNL eRHIC design has been selected over the conceptual design put forward by DOE’s Thomas Jefferson National Accelerator Facility [Jlab] as the future Electron–ion collider (EIC) in the United States.

    Electron-Ion Collider (EIC) at BNL, to be built inside the tunnel that currently houses the RHIC.

    In addition to the site selection, it was announced that the BNL EIC had acquired CD-0 (mission need) from the Department of Energy. BNL’s eRHIC design proposes upgrading the existing Relativistic Heavy Ion Collider, which collides beams light to heavy ions including polarized protons, with a polarized electron facility, to be housed in the same tunnel.

    Other discoveries

    In 1958, Brookhaven scientists created one of the world’s first video games, Tennis for Two. In 1968 Brookhaven scientists patented Maglev, a transportation technology that utilizes magnetic levitation.

    Major facilities

    Relativistic Heavy Ion Collider (RHIC), which was designed to research quark–gluon plasma[16] and the sources of proton spin. Until 2009 it was the world’s most powerful heavy ion collider. It is the only collider of spin-polarized protons.
    Center for Functional Nanomaterials (CFN), used for the study of nanoscale materials.
    National Synchrotron Light Source II (NSLS-II), Brookhaven’s newest user facility, opened in 2015 to replace the National Synchrotron Light Source (NSLS), which had operated for 30 years.[19] NSLS was involved in the work that won the 2003 and 2009 Nobel Prize in Chemistry.
    Alternating Gradient Synchrotron, a particle accelerator that was used in three of the lab’s Nobel prizes.
    Accelerator Test Facility, generates, accelerates and monitors particle beams.
    Tandem Van de Graaff, once the world’s largest electrostatic accelerator.
    Computational Science resources, including access to a massively parallel Blue Gene series supercomputer that is among the fastest in the world for scientific research, run jointly by Brookhaven National Laboratory and Stony Brook University.
    Interdisciplinary Science Building, with unique laboratories for studying high-temperature superconductors and other materials important for addressing energy challenges.
    NASA Space Radiation Laboratory, where scientists use beams of ions to simulate cosmic rays and assess the risks of space radiation to human space travelers and equipment.

    Off-site contributions

    It is a contributing partner to ATLAS experiment, one of the four detectors located at the Large Hadron Collider (LHC).

    CERN map

    Iconic view of the CERN (CH) ATLAS detector.

    It is currently operating at CERN near Geneva, Switzerland.

    Brookhaven was also responsible for the design of the SNS accumulator ring in partnership with Spallation Neutron Source at DOE’s Oak Ridge National Laboratory, Tennessee.

    ORNL Spallation Neutron Source annotated.

    Brookhaven plays a role in a range of neutrino research projects around the world, including the Daya Bay Reactor Neutrino Experiment in China and the Deep Underground Neutrino Experiment at DOE’s Fermi National Accelerator Laboratory(US).

    Daya Bay, nuclear power plant, approximately 52 kilometers northeast of Hong Kong and 45 kilometers east of Shenzhen, China

    FNAL LBNF/DUNE from FNAL to SURF, Lead, South Dakota, USA.

    Brookhaven Campus.

    BNL Center for Functional Nanomaterials.

    BNL NSLS-II.

    BNL NSLS II.

    BNL RHIC Campus.

    BNL/RHIC Star Detector.

    BNL/RHIC Phenix.

     
  • richardmitnick 6:28 pm on March 3, 2021 Permalink | Reply
    Tags: "Chemistry Goes Under Cover", , , Covering metal catalyst surfaces with thin two-dimensional oxide materials can enhance chemical reactions., DOE’s Brookhaven National Laboratory(US), In lab-based AP-XPS experiments at the CFN the team found that the temperature needed to activate the water formation reaction was lower when silica was covering ruthenium., One of the team’s unique capabilities is the ability to use complementary surface characterization tools to analyze the same sample without exposing it to air which could cause contamination., Precious metal catalysts such as palladium; platinum; or rhodium., The fact that the reaction takes place at lower temperatures in confinement is partially related to its lower activation energy., The scientists are discovering that the confined spaces modify different types of reactions and they are working to understand why., The scientists conducted infrared reflection-absorption spectroscopy (IRAAS) at the CFN., The scientists heated a calibrated amount of silicon to sublimation temperatures in a high-pressure oxygen environment., The scientitists conducted ambient-pressure x-ray photoelectron spectroscopy (AP-XPS) and mass spectrometry (MS) at the NSLS-II., The team found that a very thin layer of an inexpensive oxide can significantly boost catalytic activity without increasing the amount of the expensive precious metal used as the catalyst., The team used supercomputers to study the energetics of the reaction., The thin silica forms a two-dimensional (2-D) array of hexagonal-prism-shaped “cages” containing atoms.   

    From DOE’s Brookhaven National Laboratory(US): “Chemistry Goes Under Cover” 

    From DOE’s Brookhaven National Laboratory(US)

    March 2, 2021
    Ariana Manglaviti
    Peter Genzer

    Covering metal catalyst surfaces with thin two-dimensional oxide materials can enhance chemical reactions.

    1
    An illustration of physically confined spaces in a porous bilayer silica film on a metal catalyst that can be used for chemical reactions. Silicon atoms are indicated by the orange circles; oxygen atoms by the red circles. Nanoconfinement can occur in the pores (zero-dimensional, or 0-D) and the interface-confined region between the film and the metal (two-dimensional, 2-D).

    Physically confined spaces can make for more efficient chemical reactions, according to recent studies led by scientists from the DOE’s Brookhaven National Laboratory. They found that partially covering metal surfaces acting as catalysts, or materials that speed up reactions, with thin films of silica can impact the energies and rates of these reactions. The thin silica forms a two-dimensional (2-D) array of hexagonal-prism-shaped “cages” containing silicon and oxygen atoms.

    “These porous silica frameworks are the thickness of only three atoms,” explained Samuel Tenney, a chemist in the Interface Science and Catalysis Group of Brookhaven Lab’s Center for Functional Nanomaterials (CFN) [below]. “If the pores were too tall, certain branches of molecules wouldn’t be able to reach the interface. There’s a particular geometry in which molecules can come in and bind, sort of like the way an enzyme and a substrate lock together. Molecules with the appropriate size can slip through the pores and interact with the catalytically active metal surface.”

    “The bilayer silica is not actually anchored to the metal surface,” added Calley Eads, a research associate in the same group. “There are weak forces in between. This weak interaction allows molecules not only to penetrate the pores but also to explore the catalytic surface and find the most reactive sites and optimized reaction geometry by moving horizontally in the confined space in between the bilayer and metal. If it was anchored, the bilayer would only have one pore site for each molecule to interact with the metal.”

    The scientists are discovering that the confined spaces modify different types of reactions and they are working to understand why.

    Tenney and Eads are co-corresponding authors on recently published research in Angewandte Chemie demonstrating this confinement effect for an industrially important reaction: carbon monoxide oxidation. Carbon monoxide is a toxic component of engine exhaust from vehicles and thus must be removed. With the help of an appropriate precious metal catalysts such as palladium; platinum; or rhodium. catalytic converters in vehicles combine carbon monoxide with oxygen to form carbon dioxide.

    Tenney, Eads, and colleagues at the CFN and Brookhaven’s National Synchrotron Light Source II (NSLS-II) [below] showed that covering palladium with silica boosts the amount of carbon dioxide produced by 20 percent, as compared to the reaction on bare palladium.

    2
    A schematic showing how oxidation of carbon monoxide (CO) on palladium (Pd) under a 2-D microporous silica (SiO,2) cover produces 20 percent more carbon dioxide (CO2), as compared to the reaction on bare Pd. This interfacial microenvironment fosters a higher coverage of reactive Pd surface oxides that are key to converting CO to CO2.

    To achieve this performance enhancement, the scientists first had to get a full bilayer structure across the palladium surface. To do so, they heated a calibrated amount of silicon to sublimation temperatures in a high-pressure oxygen environment. In sublimation, a solid directly transforms into a gas. As the thin film of silica was being created, they probed its structure with low-energy electron diffraction. In this technique, electrons striking a material diffract in a pattern characteristic of the material’s crystalline structure.

    “We continue heating until we get highly crystalline structures with well-defined pore sizes that we can use to explore the chemistry we’re interested in,” said Eads.

    Here, the team tracked reactants and products and the chemical bonding environment in the 2-D confined space during oxidation of carbon monoxide, incrementally increasing the temperature. To track this information, they simultaneously conducted ambient-pressure x-ray photoelectron spectroscopy (AP-XPS) and mass spectrometry (MS) at the NSLS-II [below] and infrared reflection-absorption spectroscopy (IRAAS) at the CFN.

    “AP-XPS tells us what elements are present, whether they’re on the surface or in the gas phase,” said Tenney. “It can also give us information about the chemical oxidation state or binding geometry of the atoms—whether a carbon is bound to one or two oxygen atoms, for example. MS helps us identify the gas-phase molecules we’re seeing evolve in our system on the basis of their weight and charge. IRRAS is a fingerprint of the type of chemical bonds present between atoms and shows the conformation and orientation of carbon monoxide molecules adsorbed on the surface.”

    According to co-author Dario Stacchiola, leader of the CFN Interface Science and Catalysis Group, one of the team’s unique capabilities is the ability to use complementary surface characterization tools to analyze the same sample without exposing it to air which could cause contamination.

    “Reproducibility is often a problem in catalysis,” said Stacchiola. “But we have a setup that allows us to prepare a sample in very pristine ultrahigh-vacuum conditions and expose the same sample to industrially relevant pressures of gases.”

    3
    Growth and characterization of a bilayer silica film using a low-energy electron microscope (LEEM) with full-field imaging. This type of microscopy allows scientists to follow changes in the structure of the film as it’s growing in real time. Figure (a) shows a clean palladium surface imaged with LEEM (large sphere) and its accompanying electron diffraction pattern (small sphere). Figure (b) shows the imaging and diffraction patterns for bilayer silica (SiO2) grown on palladium.

    The experimental results showed a sharp rise in the amount of carbon dioxide above a critical temperature. Below this temperature, carbon monoxide “poisons” the surface, preventing the reaction from proceeding. However, once the temperature threshold is met, molecular oxygen begins to split into two individual oxygen atoms on the palladium surface and form a surface oxide. These oxygen atoms combine with carbon monoxide to form carbon dioxide, thereby preventing poisoning.

    “The confined space is changing the energetics and kinetics of the reaction to produce more carbon dioxide,” said Eads, who led the recent implementation of this new multimodal surface analysis approach for studying nanoporous films under operational conditions.

    “By applying thin films on top of a traditional catalyst that has been studied for decades, we’ve introduced a “knob” to tailor the chemistry for certain reactions,” said Tenney. “Even a one-percent improvement in catalyst efficiency can translate into economic savings in large-scale production.”

    “We found that a very thin layer of an inexpensive oxide can significantly boost catalytic activity without increasing the amount of the expensive precious metal used as the catalyst,” added Stacchiola.

    4
    An illustration of the impact of bilayer silica on biomass conversion. Bulky biomass molecules such as furfuryl alcohol can only infiltrate the silica film at pore defect sites to interact with catalytically active palladium. Once trapped below the silica cover, furfuryl alcohol can break down into several derivatives, notably propane, which is difficult to produce on the open surface.

    Previously, the team studied [J Phys. Chem. C] the dynamics of the furfuryl alcohol reaction on a palladium surface covered by bilayer silica. Furfuryl alcohol is a biomass-derived molecule that can be converted into biofuel. Compared to carbon monoxide oxidation, which only makes a single product, reactions with larger and more complex biomolecules such as furfuryl alcohol can generate many undesired byproducts. Their preliminary data showed the potential for tuning the selectivity of the furfuryl alcohol reaction with the bilayer silica cover.

    “Changing catalytic activity is great—that’s what we see in the carbon monoxide oxidation study,” said Stacchiola. “The next step is to prove that we can use the oxide covers to tune the selectivity for particular reactions. We think our approach can be applied broadly in catalysis.”

    Last year, other members of Stacchiola’s group—along with colleagues from the CFN Theory and Computation Group, Stony Brook University (SBU), and University of Wisconsin–Milwaukee—published a related study in ACS Catalysis, a journal of the American Chemical Society (ACS). Combining experiment and theory, they discovered why the water formation reaction catalyzed by ruthenium metal is accelerated under confinement with bilayer silica.

    5
    The research on accelerated water formation on ruthenium under the cover of a silica bilayer was published in ACS Catalysis in 2020 and featured on the journal cover.

    “Chemistry in confined spaces is quite a new area of research,” said co-corresponding author Deyu Lu, a physicist in the CFN Theory and Computation Group. “In the last decade, there have been many reports that confinement impacts the chemistry, but a mechanistic understanding on the atomic scale has been largely lacking.”

    In the ACS Catalysis study, the CFN team demonstrated that confinement can change the pathway by which the reaction occurs. Water formation can proceed by two possible reaction pathways: direct hydrogenation and disproportionation. The main difference is how the first hydroxyl group—oxygen bonded to hydrogen—is made. According to calculations by Lu and first author and SBU student Mengen Wang—this reaction step costs the most energy.

    In the direct pathway, hydrogen molecules dissociate on the surface into two hydrogen atoms, which combine with a chemically absorbed oxygen on the surface. These hydroxyl groups combine with another hydrogen atom to make water. For the disproportionation pathway, water—which may still initially come from the direct pathway—first needs to be stabilized on the surface. Then, water can combine with a surface oxygen to make two hydroxyl groups on the surface. These hydroxyl groups can join with two hydrogen atoms to form two water molecules. These water molecules can then make more hydroxyl groups, forming a loop in the disproportionation pathway.

    In lab-based AP-XPS experiments at the CFN, the team found that the temperature needed to activate the water formation reaction was much lower when silica was covering ruthenium, as compared to the metal by itself.

    “The fact that the reaction takes place at lower temperatures in confinement is partially related to its lower activation energy,” explained co-corresponding author Anibal Boscoboinik, a chemist in the CFN Interface Science and Catalysis Group. “From the AP-XPS data on surface oxygen, we can indirectly derive the energy required to activate the reaction. We see that this activation energy is much lower when silica is on top of ruthenium.”

    Applying a popular computational method called density functional theory, the team used supercomputers to study the energetics of the reaction. Initially, the experimentalists hypothesized that the lowered activation energy for the rate-limiting step of the reaction (making the first hydroxyl group) was due to silica pressing down on the reaction complex. However, the calculations showed that the presence of silica didn’t change this energy significantly. Rather, it changed the reaction pathway. On the bare ruthenium surface, the direct pathway was favored; in the presence of silica, water molecules stabilized on the surface, activating the disproportionation pathway.

    6
    (Left to right) Anibal Boscoboinik, Calley Eads, Deyu Lu, Dario Stacchiola, and Samuel Tenney of Brookhaven Lab’s Center for Functional Nanomaterials are among a team of scientists studying chemistry in confined spaces.

    “Without the silica cover, the water molecules desorb, and the reaction follows the direct pathway,” said Lu. “Under the silica cover, water needs to cross several kinetic energy barriers in order to leave the surface. These kinetic barriers trap water molecules on the metal surface and activate the disproportionation pathway, enabling the hydroxyl groups to be made at a much lower energy barrier, as compared to the case without the confinement effects.”

    Though water formation isn’t industrially relevant, the scientists say studying this model reaction can help them understand how to leverage the confinement effects to favor certain reaction pathways for more relevant reactions. In other words, the same fundamental principle can be applied to other systems. For example, silica could be coated onto electrodes to evoke particular pathways at liquid-solid interfaces in electrochemical cells. In that case, the reaction would be the opposite—water would be dissociated into oxygen and hydrogen, a clean fuel.

    “Understanding this reaction helps us to understand the reverse reaction,” said Boscoboinik, who recently published a summary of initial studies on confinement effects with 2-D porous thin films. “If we were guided by experiment alone, we would have attributed the wrong explanation. Theory proved that our initial hypothesis was incorrect and played a key role in revealing the correct reaction mechanism at the microscopic level.”

    7
    (Left) Without a silica cover, xenon (Xe) weakly adsorbs on ruthenium (Ru). (Right) With a silica cover, Xe strongly adsorbs on Ru because of interface confinement.

    Yet, the scientists have seen other examples where silica has a pressure-related effect. In 2019, they found that bilayer silica presses down on the noble gas xenon at the interface between bilayer silica and ruthenium, inducing stronger bonding between xenon and ruthenium.

    “Different effects arise from confinement,” said Stacchiola. “It’s a very interesting, rich, and mostly unexplored area. We’re excited to keep investigating chemistry in confined spaces in the coming years.”

    The research was partially supported by the DOE Office of Science and Integrated Mesoscale Architectures for Sustainable Catalysis, a DOE Energy Frontier Research Center. Experiments at the CFN were carried out in the Proximal Probes Facility. The computations were run at the Scientific Data and Computing Center, which is part of Brookhaven’s Computational Science Initiative, and the National Energy Research Scientific Computing Center (NERSC). The AP-XPS measurements were done at the In Situ and Operando Soft X-ray Spectroscopy (IOS) beamline at an endstation built in partnership between the CFN and NSLS-II. The CFN, NERSC, and NSLS-II are all DOE Office of Science User Facilities.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    One of ten national laboratories overseen and primarily funded by the DOE(US) Office of Science, DOE’s Brookhaven National Laboratory(US) conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University(US), the largest academic user of Laboratory facilities, and Battelle(US), a nonprofit, applied science and technology organization.

    Research at BNL specializes in nuclear and high energy physics, energy science and technology, environmental and bioscience, nanoscience and national security. The 5,300 acre campus contains several large research facilities, including the Relativistic Heavy Ion Collider [below] and National Synchrotron Light Source II [below]. Seven Nobel prizes have been awarded for work conducted at Brookhaven lab.

    BNL is staffed by approximately 2,750 scientists, engineers, technicians, and support personnel, and hosts 4,000 guest investigators every year. The laboratory has its own police station, fire department, and ZIP code (11973). In total, the lab spans a 5,265-acre (21 km^2) area that is mostly coterminous with the hamlet of Upton, New York. BNL is served by a rail spur operated as-needed by the New York and Atlantic Railway. Co-located with the laboratory is the Upton, New York, forecast office of the National Weather Service.

    Major programs

    Although originally conceived as a nuclear research facility, Brookhaven Lab’s mission has greatly expanded. Its foci are now:

    Nuclear and high-energy physics
    Physics and chemistry of materials
    Environmental and climate research
    Nanomaterials
    Energy research
    Nonproliferation
    Structural biology
    Accelerator physics

    Operation

    Brookhaven National Lab was originally owned by the Atomic Energy Commission(US) and is now owned by that agency’s successor, the United States Department of Energy (DOE). DOE subcontracts the research and operation to universities and research organizations. It is currently operated by Brookhaven Science Associates LLC, which is an equal partnership of Stony Brook University(US) and Battelle Memorial Institute(US). From 1947 to 1998, it was operated by Associated Universities, Inc. (AUI), but AUI lost its contract in the wake of two incidents: a 1994 fire at the facility’s high-beam flux reactor that exposed several workers to radiation and reports in 1997 of a tritium leak into the groundwater of the Long Island Central Pine Barrens on which the facility sits.

    Foundations

    Following World War II, the US Atomic Energy Commission was created to support government-sponsored peacetime research on atomic energy. The effort to build a nuclear reactor in the American northeast was fostered largely by physicists Isidor Isaac Rabi and Norman Foster Ramsey Jr., who during the war witnessed many of their colleagues at Columbia University leave for new remote research sites following the departure of the Manhattan Project from its campus. Their effort to house this reactor near New York City was rivalled by a similar effort at the Massachusetts Institute of Technology(US) to have a facility near Boston, Massachusettes(US). Involvement was quickly solicited from representatives of northeastern universities to the south and west of New York City such that this city would be at their geographic center. In March 1946 a nonprofit corporation was established that consisted of representatives from nine major research universities — Columbia(US), Cornell(US), Harvard(US), Johns Hopkins(US), MIT, Princeton University(US), University of Pennsylvania(US), University of Rochester(US), and Yale University(US).

    Out of 17 considered sites in the Boston-Washington corridor, Camp Upton on Long Island was eventually chosen as the most suitable in consideration of space, transportation, and availability. The camp had been a training center from the US Army during both World War I and World War II. After the latter war, Camp Upton was deemed no longer necessary and became available for reuse. A plan was conceived to convert the military camp into a research facility.

    On March 21, 1947, the Camp Upton site was officially transferred from the U.S. War Department to the new U.S. Atomic Energy Commission (AEC), predecessor to the U.S. Department of Energy (DOE).

    Research and facilities

    Reactor history

    In 1947 construction began on the first nuclear reactor at Brookhaven, the Brookhaven Graphite Research Reactor. This reactor, which opened in 1950, was the first reactor to be constructed in the United States after World War II. The High Flux Beam Reactor operated from 1965 to 1999. In 1959 Brookhaven built the first US reactor specifically tailored to medical research, the Brookhaven Medical Research Reactor, which operated until 2000.

    Accelerator history

    In 1952 Brookhaven began using its first particle accelerator, the Cosmotron. At the time the Cosmotron was the world’s highest energy accelerator, being the first to impart more than 1 GeV of energy to a particle.

    BNL Cosmotron 1952-1966

    The Cosmotron was retired in 1966, after it was superseded in 1960 by the new Alternating Gradient Synchrotron (AGS).

    BNL Alternating Gradient Synchrotron (AGS)

    The AGS was used in research that resulted in 3 Nobel prizes, including the discovery of the muon neutrino, the charm quark, and CP violation.

    In 1970 in BNL started the ISABELLE project to develop and build two proton intersecting storage rings.

    The groundbreaking for the project was in October 1978. In 1981, with the tunnel for the accelerator already excavated, problems with the superconducting magnets needed for the ISABELLE accelerator brought the project to a halt, and the project was eventually cancelled in 1983.

    The National Synchrotron Light Source operated from 1982 to 2014 and was involved with two Nobel Prize-winning discoveries. It has since been replaced by the National Synchrotron Light Source II [below].

    BNL NSLS.

    After ISABELLE’S cancellation, physicist at BNL proposed that the excavated tunnel and parts of the magnet assembly be used in another accelerator. In 1984 the first proposal for the accelerator now known as the Relativistic Heavy Ion Collider (RHIC)[below] was put forward. The construction got funded in 1991 and RHIC has been operational since 2000. One of the world’s only two operating heavy-ion colliders, RHIC is as of 2010 the second-highest-energy collider after the Large Hadron Collider(CH). RHIC is housed in a tunnel 2.4 miles (3.9 km) long and is visible from space.

    On January 9, 2020, It was announced by Paul Dabbar, undersecretary of the US Department of Energy Office of Science, that the BNL eRHIC design has been selected over the conceptual design put forward by DOE’s Thomas Jefferson National Accelerator Facility [Jlab] as the future Electron–ion collider (EIC) in the United States.

    Electron-Ion Collider (EIC) at BNL, to be built inside the tunnel that currently houses the RHIC.

    In addition to the site selection, it was announced that the BNL EIC had acquired CD-0 (mission need) from the Department of Energy. BNL’s eRHIC design proposes upgrading the existing Relativistic Heavy Ion Collider, which collides beams light to heavy ions including polarized protons, with a polarized electron facility, to be housed in the same tunnel.

    Other discoveries

    In 1958, Brookhaven scientists created one of the world’s first video games, Tennis for Two. In 1968 Brookhaven scientists patented Maglev, a transportation technology that utilizes magnetic levitation.

    Major facilities

    Relativistic Heavy Ion Collider (RHIC), which was designed to research quark–gluon plasma[16] and the sources of proton spin. Until 2009 it was the world’s most powerful heavy ion collider. It is the only collider of spin-polarized protons.
    Center for Functional Nanomaterials (CFN), used for the study of nanoscale materials.
    National Synchrotron Light Source II (NSLS-II), Brookhaven’s newest user facility, opened in 2015 to replace the National Synchrotron Light Source (NSLS), which had operated for 30 years.[19] NSLS was involved in the work that won the 2003 and 2009 Nobel Prize in Chemistry.
    Alternating Gradient Synchrotron, a particle accelerator that was used in three of the lab’s Nobel prizes.
    Accelerator Test Facility, generates, accelerates and monitors particle beams.
    Tandem Van de Graaff, once the world’s largest electrostatic accelerator.
    Computational Science resources, including access to a massively parallel Blue Gene series supercomputer that is among the fastest in the world for scientific research, run jointly by Brookhaven National Laboratory and Stony Brook University.
    Interdisciplinary Science Building, with unique laboratories for studying high-temperature superconductors and other materials important for addressing energy challenges.
    NASA Space Radiation Laboratory, where scientists use beams of ions to simulate cosmic rays and assess the risks of space radiation to human space travelers and equipment.

    Off-site contributions

    It is a contributing partner to ATLAS experiment, one of the four detectors located at the Large Hadron Collider (LHC).

    CERN map

    Iconic view of the CERN (CH) ATLAS detector.

    It is currently operating at CERN near Geneva, Switzerland.

    Brookhaven was also responsible for the design of the SNS accumulator ring in partnership with Spallation Neutron Source at DOE’s Oak Ridge National Laboratory, Tennessee.

    ORNL Spallation Neutron Source annotated.

    Brookhaven plays a role in a range of neutrino research projects around the world, including the Daya Bay Reactor Neutrino Experiment in China and the Deep Underground Neutrino Experiment at DOE’s Fermi National Accelerator Laboratory(US).

    Daya Bay, nuclear power plant, approximately 52 kilometers northeast of Hong Kong and 45 kilometers east of Shenzhen, China

    FNAL LBNF/DUNE from FNAL to SURF, Lead, South Dakota, USA.

    Brookhaven Campus.

    BNL Center for Functional Nanomaterials.

    BNL NSLS-II.

    BNL NSLS II.

    BNL RHIC Campus.

    BNL/RHIC Star Detector.

    BNL/RHIC Phenix.

     
  • richardmitnick 10:15 am on February 26, 2021 Permalink | Reply
    Tags: "'Forward' Jet-tracking Components Installed at RHIC's STAR Detector", , , , DOE’s Brookhaven National Laboratory(US), , Just prior to the start of this year’s run at the (RHIC) a team of scientists; engineers; technicians; and students completed the installation of new components of the collider’s STAR detector., New calorimeters will give scientists a glimpse of the internal structure of protons and nuclei in particle smash-ups at the Relativistic Heavy Ion Collider., , ,   

    From DOE’s Brookhaven National Laboratory(US): “‘Forward’ Jet-tracking Components Installed at RHIC’s STAR Detector” 

    From DOE’s Brookhaven National Laboratory(US)

    February 22, 2021
    Karen McNulty Walsh
    kmcnulty@bnl.gov

    New calorimeters will give scientists a glimpse of the internal structure of protons and nuclei in particle smash-ups at the Relativistic Heavy Ion Collider.

    1
    A view through the STAR endcap magnet at the new calorimeter components installed in the “forward” direction. These components will allow physicists to measure and reconstruct the energy of jets from particles emerging close to the beamline.

    Just prior to the start of this year’s run at the Relativistic Heavy Ion Collider (RHIC) [below]—a U.S. Department of Energy Office of Science user facility for nuclear physics research at DOE’s Brookhaven National Laboratory—a team of scientists; engineers; technicians; and students completed the installation of important new components of the collider’s STAR [below] detector. This house-sized particle tracker (the Solenoidal Tracker at RHIC) captures the subatomic debris created when atomic nuclei collide so scientists can learn about the building blocks of matter. The new components will expand STAR’s ability to track jets of particles emerging in an extreme “forward” direction, meaning close to the beamline through which the particles travel as they collide.

    Forward jet detection will be important for learning how the internal components of protons and neutrons—quarks and gluons—contribute to the overall properties of these building blocks of matter.

    1
    Brookhaven Lab physicist Elke Caroline Aschenauer is leading the STAR Forward Upgrade project.

    “Jets are excellent surrogates for quarks and gluons,” said Brookhaven Lab physicist Elke-Caroline Aschenauer, who leads the STAR forward upgrade. “If you measure the energy of all the particles that make up a jet, then you basically know everything about the quark or gluon that produced that jet during the collision—its energy, direction, and spin.” Measuring many jets will allow scientists to map the 3-D structure of the proton, including the arrangement and spin of the quarks and gluons within.

    The new equipment won’t be used for physics measurements until next year’s run of RHIC experiments at high energy. But having the major components—two kinds of calorimeters—installed for this year’s low-energy run gives physicists a chance to calibrate the equipment and work out any kinks.

    “We can use this time to get all the data-acquisition systems running, test the read-out channels, and commission our trigger setup”—the system that decides, in a fraction of a second, which collisions to record and which to toss, Aschenauer said.

    Separated by space and time

    Meeting the deadline for the start of this year’s RHIC run in the midst of a global pandemic was no small task.

    3
    This schematic rendering of the STAR detector shows the components that make up the forward upgrade. The hadronic calorimeter (violet blocks at the far end of the illustration) and electromagnetic calorimeter (pink blocks closer in) are in place for this year’s run. Four “small-strip thin-gap-chamber” disks (light violet) and three silicon disks (multicolor) surrounding the beampipe make up the tracker and will be installed this summer.

    “We wanted to have lots of academic ‘users’ of the STAR experiment and their students go to Brookhaven to assemble and install the components, but with COVID, that became very complicated,” said Oleg Tsai, a STAR user from UCLA(US) and the creative mind behind the forward detector design.

    Instead, the project moved forward as a collaboration separated by space and time.

    “STAR users at universities across the country worked to build and test components with students—including some who lived too far from home to travel during lockdown,” Tsai said.

    To maintain social distance, “we naturally split off into morning and afternoon groups,” said David Kapukchyan, a graduate student who helped assemble components at the University of California, Riverside(US). “We had to leave notes for each other so that each group knew what they had to do for their time in the lab.”

    “This experience has given me great insight into how detectors of this size come together and the amount of work it takes to build them,” he added.

    4
    Some of the Brookhaven Lab Collider-Accelerator Department staff who helped with the installation of calorimeter components at STAR (left to right): Edward Dabrowski, Adrian Timon, Matthew Ceglia, Travis Herbst, and Dennis Carlson.

    That satisfied a key goal for Scott Wissink, a STAR user and physics professor at Indiana University(US), who coordinated the proposal to fund this work through the National Science Foundation’s Major Research Instrumentation (MRI) program, which specifically included support for student participation at the ten universities that made up the project consortium.

    “In addition to buying materials and equipment, we also requested funds to support the technical workforce required at the individual universities, and especially to provide opportunities for students to get involved in the testing and assembly of the components,” he said. “This experience will not only ensure that we have the right equipment to carry out the measurements, but will also prepare them to lead the next generation of physics experiments.”

    Assisted assembly

    “The pieces were produced and delivered from everywhere in the world—Indiana, Pennsylvania, California, Illinois, Texas—even China and Japan. When we couldn’t get toilet paper we were getting scintillators,” Aschenauer noted, describing special plastic that detects particles of light. Then all the pieces—tens of thousands of components—had to be assembled and installed in a Lego-like fashion, layer by layer, she said.

    5
    An array of 520 calorimeter towers, each consisting of 36 steel absorber blocks interleaved with scintillator tiles and the pins that hold them together.

    Some students were ultimately able to help.

    “I had plans to come to Brookhaven for my doctoral studies before the COVID pandemic hit,” said Erik Loyd, another grad student at UC Riverside. “Though my travel was initially delayed, I ended up moving to New York and quarantining for a month before coming to the Lab to help with installation.”

    But with far fewer students available than in normal times, the project leaders turned to technicians in Brookhaven’s Beam & Experimental Services (B&ES) group and the Collider-Accelerator Support (CAS) group for additional assistance.

    Brendan Hoy, a member of CAS, noted that his group’s round-the-clock duties typically consist of responding to real time equipment issues—troubleshooting and performing corrective maintenance on things like power supplies and magnets—as well as building, installing, and maintaining various electronic systems around the complex. “The work we do maintaining STAR power supplies and the electronics-centric nature of my regularly assigned duties mapped on to this detector install very well,” he said. “Given the uniquely difficult circumstances that 2020 brought to us all, I found the opportunity to work on a project outside of the normal scope of my role to be a welcome one.”

    6
    This image shows one half of the hadronic calorimeter (260 blocks). In the front one can see the electromagnetic calorimeter with all its readout electronics and cables fully installed.

    “The Collider-Accelerator Department (CAD) technicians, working with the STAR Technical Support Group, did a great job installing the calorimeters and their support structures,” said Rahul Sharma, STAR’s chief engineer. “The work went twice as fast as originally anticipated, with groups working in alternating shifts in the morning and afternoon to stack multiple layers of the detector blocks. It was a real challenge to try coordinate all this for over three months to complete the installation.”

    “We had to overcome many challenges while building these detectors in such a tight location and time frame,” said Travis Herbst, a technician in B&ES. “Due to the limited space, we had to install a temporary conveyor belt that allowed us to transfer almost 10,000 steel absorber blocks weighing 15 tons and 20,000 pins used to hold them together under the beam line so we could build the detectors on both sides.”

    Adrian Timon, another B&ES technician, added: “We also had to maintain social distance during all the working hours needed for installing the detector while inspecting and keeping all of the blocks and pins cleaned of debris or deformity, as such defects could cause problems with the detector’s internal structure.”

    “The most amazing thing for me was all these minor details that you don’t read about in a textbook when they describe these calorimeters,” said UC Riverside’s Kapukchyan, who also travelled to Long Island for the assembly. “You read about the physics of how particles lose energy and how to calculate it, but all these minor construction details, like how to correctly unspool cables, are left out. Being involved [through all stages of this project] was a great experience for me and will certainly help me in my future endeavors,” he said.

    7
    Students, STAR external users, and technical support group members who participated in the installation in the STAR detector assembly area outside the detector.

    Pushing science forward

    The now-complete Lego-like calorimeter assemblies will be joined, after this year’s run, by a few additional components—two kinds of tracking detectors for discerning particles with different electrical charges. The whole system will then be ready to collect physics data in the 2022 RHIC run.

    Positioned at one end of the STAR detector’s barrel-shaped Time Projection Chamber, the calorimeters and trackers will capture jets that emerge at angles very close to RHIC’s beamline, exiting at that end of the barrel. Studying those particular jets is important because they give scientists access to the quarks and gluons that carry either a very high or very low percentage of the proton’s (or nucleus’s) overall momentum.

    8
    One half of the hadronic calorimeter, made of 20 x 13 towers, with the first two readout electronics boards installed and the all the signal cables bringing the light from the photon sensors to the readout boards.

    Jets produced by scattering off the three main valence quarks that make up a proton carry a large percentage of the particle’s overall momentum. But a proton is much more complex than those three main quarks. Inside there is a teeming microcosm of quark and antiquark pairs that flit in and out of existence. Gluons—aptly named because they glue the quarks together—are even more mysterious. They split and multiply and, at high energies, may completely dominate the structure of the proton. Each of these gluons carries a tiny percentage of the proton’s overall momentum. But because there are so many of them, scientists believe their combined influence plays an outsized role in establishing the proton’s properties. Hence the motivation to study jets generated by these “low-momentum-fraction” gluons.

    “These measurements will help us search for evidence that the gold ions we collide at RHIC become dense walls of gluons, and that this saturated state of gluons is responsible for key properties such as proton spin and mass, as suggested by many of the findings we’ve already observed at RHIC,” Aschenauer said.

    The measurements will also help lay the groundwork for jet-tracking at the future Electron-Ion Collider (EIC). The EIC is a new state-of-the-art DOE nuclear physics facility to be built at Brookhaven Lab in collaboration with Thomas Jefferson National Accelerator Facility (Jefferson Lab) to expand scientists’ reach into the frontiers of nuclear physics.

    “The hadronic calorimeter design we are talking about for the EIC has components that are basically identical to the one that is part of this upgrade, so that part of this project serves as a prototype for future EIC detector components,” Aschenauer said.

    The STAR Forward Upgrade receives funding from several sources. University partners’ contributions to the calorimeter system were funded by the National Science Foundation; contributions by scientists and technical staff at Brookhaven Lab were funded by the DOE Office of Science, which also supports RHIC operations. Development of the tracking detectors (yet to be installed) is partially supported by funding from the National Natural Science Foundation of China, the Ministry of Science and Technology of China, the Chinese Ministry of Education, Key Laboratory of Particle Physics and Particle Irradiation of China, the Higher Education Sprout Project by Ministry of Education at National Cheng Kung University.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    One of ten national laboratories overseen and primarily funded by the DOE(US) Office of Science, DOE’s Brookhaven National Laboratory(US) conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University(US), the largest academic user of Laboratory facilities, and Battelle(US), a nonprofit, applied science and technology organization.

    Research at BNL specializes in nuclear and high energy physics, energy science and technology, environmental and bioscience, nanoscience and national security. The 5,300 acre campus contains several large research facilities, including the Relativistic Heavy Ion Collider [below] and National Synchrotron Light Source II [below]. Seven Nobel prizes have been awarded for work conducted at Brookhaven lab.

    BNL is staffed by approximately 2,750 scientists, engineers, technicians, and support personnel, and hosts 4,000 guest investigators every year. The laboratory has its own police station, fire department, and ZIP code (11973). In total, the lab spans a 5,265-acre (21 km^2) area that is mostly coterminous with the hamlet of Upton, New York. BNL is served by a rail spur operated as-needed by the New York and Atlantic Railway. Co-located with the laboratory is the Upton, New York, forecast office of the National Weather Service.

    Major programs

    Although originally conceived as a nuclear research facility, Brookhaven Lab’s mission has greatly expanded. Its foci are now:

    Nuclear and high-energy physics
    Physics and chemistry of materials
    Environmental and climate research
    Nanomaterials
    Energy research
    Nonproliferation
    Structural biology
    Accelerator physics

    Operation

    Brookhaven National Lab was originally owned by the Atomic Energy Commission(US) and is now owned by that agency’s successor, the United States Department of Energy (DOE). DOE subcontracts the research and operation to universities and research organizations. It is currently operated by Brookhaven Science Associates LLC, which is an equal partnership of Stony Brook University(US) and Battelle Memorial Institute(US). From 1947 to 1998, it was operated by Associated Universities, Inc. (AUI), but AUI lost its contract in the wake of two incidents: a 1994 fire at the facility’s high-beam flux reactor that exposed several workers to radiation and reports in 1997 of a tritium leak into the groundwater of the Long Island Central Pine Barrens on which the facility sits.

    Foundations

    Following World War II, the US Atomic Energy Commission was created to support government-sponsored peacetime research on atomic energy. The effort to build a nuclear reactor in the American northeast was fostered largely by physicists Isidor Isaac Rabi and Norman Foster Ramsey Jr., who during the war witnessed many of their colleagues at Columbia University leave for new remote research sites following the departure of the Manhattan Project from its campus. Their effort to house this reactor near New York City was rivalled by a similar effort at the Massachusetts Institute of Technology(US) to have a facility near Boston, Massachusettes(US). Involvement was quickly solicited from representatives of northeastern universities to the south and west of New York City such that this city would be at their geographic center. In March 1946 a nonprofit corporation was established that consisted of representatives from nine major research universities — Columbia(US), Cornell(US), Harvard(US), Johns Hopkins(US), MIT, Princeton University(US), University of Pennsylvania(US), University of Rochester(US), and Yale University(US).

    Out of 17 considered sites in the Boston-Washington corridor, Camp Upton on Long Island was eventually chosen as the most suitable in consideration of space, transportation, and availability. The camp had been a training center from the US Army during both World War I and World War II. After the latter war, Camp Upton was deemed no longer necessary and became available for reuse. A plan was conceived to convert the military camp into a research facility.

    On March 21, 1947, the Camp Upton site was officially transferred from the U.S. War Department to the new U.S. Atomic Energy Commission (AEC), predecessor to the U.S. Department of Energy (DOE).

    Research and facilities

    Reactor history

    In 1947 construction began on the first nuclear reactor at Brookhaven, the Brookhaven Graphite Research Reactor. This reactor, which opened in 1950, was the first reactor to be constructed in the United States after World War II. The High Flux Beam Reactor operated from 1965 to 1999. In 1959 Brookhaven built the first US reactor specifically tailored to medical research, the Brookhaven Medical Research Reactor, which operated until 2000.

    Accelerator history

    In 1952 Brookhaven began using its first particle accelerator, the Cosmotron. At the time the Cosmotron was the world’s highest energy accelerator, being the first to impart more than 1 GeV of energy to a particle.

    BNL Cosmotron 1952-1966

    The Cosmotron was retired in 1966, after it was superseded in 1960 by the new Alternating Gradient Synchrotron (AGS).

    BNL Alternating Gradient Synchrotron (AGS)

    The AGS was used in research that resulted in 3 Nobel prizes, including the discovery of the muon neutrino, the charm quark, and CP violation.

    In 1970 in BNL started the ISABELLE project to develop and build two proton intersecting storage rings.

    The groundbreaking for the project was in October 1978. In 1981, with the tunnel for the accelerator already excavated, problems with the superconducting magnets needed for the ISABELLE accelerator brought the project to a halt, and the project was eventually cancelled in 1983.

    The National Synchrotron Light Source operated from 1982 to 2014 and was involved with two Nobel Prize-winning discoveries. It has since been replaced by the National Synchrotron Light Source II [below].

    BNL NSLS.

    After ISABELLE’S cancellation, physicist at BNL proposed that the excavated tunnel and parts of the magnet assembly be used in another accelerator. In 1984 the first proposal for the accelerator now known as the Relativistic Heavy Ion Collider (RHIC)[below] was put forward. The construction got funded in 1991 and RHIC has been operational since 2000. One of the world’s only two operating heavy-ion colliders, RHIC is as of 2010 the second-highest-energy collider after the Large Hadron Collider(CH). RHIC is housed in a tunnel 2.4 miles (3.9 km) long and is visible from space.

    On January 9, 2020, It was announced by Paul Dabbar, undersecretary of the US Department of Energy Office of Science, that the BNL eRHIC design has been selected over the conceptual design put forward by DOE’s Thomas Jefferson National Accelerator Facility [Jlab] as the future Electron–ion collider (EIC) in the United States.

    Electron-Ion Collider (EIC) at BNL, to be built inside the tunnel that currently houses the RHIC.

    In addition to the site selection, it was announced that the BNL EIC had acquired CD-0 (mission need) from the Department of Energy. BNL’s eRHIC design proposes upgrading the existing Relativistic Heavy Ion Collider, which collides beams light to heavy ions including polarized protons, with a polarized electron facility, to be housed in the same tunnel.

    Other discoveries

    In 1958, Brookhaven scientists created one of the world’s first video games, Tennis for Two. In 1968 Brookhaven scientists patented Maglev, a transportation technology that utilizes magnetic levitation.

    Major facilities

    Relativistic Heavy Ion Collider (RHIC), which was designed to research quark–gluon plasma[16] and the sources of proton spin. Until 2009 it was the world’s most powerful heavy ion collider. It is the only collider of spin-polarized protons.
    Center for Functional Nanomaterials (CFN), used for the study of nanoscale materials.
    National Synchrotron Light Source II (NSLS-II), Brookhaven’s newest user facility, opened in 2015 to replace the National Synchrotron Light Source (NSLS), which had operated for 30 years.[19] NSLS was involved in the work that won the 2003 and 2009 Nobel Prize in Chemistry.
    Alternating Gradient Synchrotron, a particle accelerator that was used in three of the lab’s Nobel prizes.
    Accelerator Test Facility, generates, accelerates and monitors particle beams.
    Tandem Van de Graaff, once the world’s largest electrostatic accelerator.
    Computational Science resources, including access to a massively parallel Blue Gene series supercomputer that is among the fastest in the world for scientific research, run jointly by Brookhaven National Laboratory and Stony Brook University.
    Interdisciplinary Science Building, with unique laboratories for studying high-temperature superconductors and other materials important for addressing energy challenges.
    NASA Space Radiation Laboratory, where scientists use beams of ions to simulate cosmic rays and assess the risks of space radiation to human space travelers and equipment.

    Off-site contributions

    It is a contributing partner to ATLAS experiment, one of the four detectors located at the Large Hadron Collider (LHC).

    CERN map

    Iconic view of the CERN (CH) ATLAS detector.

    It is currently operating at CERN near Geneva, Switzerland.

    Brookhaven was also responsible for the design of the SNS accumulator ring in partnership with Spallation Neutron Source at DOE’s Oak Ridge National Laboratory, Tennessee.

    ORNL Spallation Neutron Source annotated.

    Brookhaven plays a role in a range of neutrino research projects around the world, including the Daya Bay Reactor Neutrino Experiment in China and the Deep Underground Neutrino Experiment at DOE’s Fermi National Accelerator Laboratory(US).

    Daya Bay, nuclear power plant, approximately 52 kilometers northeast of Hong Kong and 45 kilometers east of Shenzhen, China

    FNAL LBNF/DUNE from FNAL to SURF, Lead, South Dakota, USA.

    Brookhaven Campus.

    BNL Center for Functional Nanomaterials.

    BNL NSLS-II.

    BNL NSLS II.

    BNL RHIC Campus.

    BNL/RHIC Star Detector.

    BNL/RHIC Phenix.

     
  • richardmitnick 9:44 am on February 20, 2021 Permalink | Reply
    Tags: "Tuning Electrode Surfaces to Optimize Solar Fuel Production", , Bismuth vanadate, , , Combining STM and LEIS allowed the scientists to identify the atomic structure and chemical elements on the topmost surface layer of this photoelectrode material., DOE’s Brookhaven National Laboratory(US), Interfacial energetics, LEIS-Low-energy ion scattering spectroscopy, Photoelectrochemical performance, Photoelectrodes, , , The experimental and computational results both indicated that the bismuth-rich surfaces lead to more favorable surface energetics and improved photoelectrochemical properties for water splitting., X-ray photoelectron spectroscopy   

    From DOE’s Brookhaven National Laboratory(US): “Tuning Electrode Surfaces to Optimize Solar Fuel Production” 

    From DOE’s Brookhaven National Laboratory(US)

    February 18, 2021
    Ariana Manglaviti
    amanglaviti@bnl.gov
    (631) 344-2347

    Peter Genzer
    genzer@bnl.gov
    (631) 344-3174

    An electrode material with modified surface atoms generates more electrical current, which drives the sunlight-powered reactions that split water into oxygen and hydrogen—a clean fuel.

    1
    Through a tight coupling of experiment and theory, scientists showed at the atomic level how changes in the surface composition of a photoelectrode play a critical role in photoelectrochemical performance.

    Scientists have demonstrated that modifying the topmost layer of atoms on the surface of electrodes can have a remarkable impact on the activity of solar water splitting. As they reported in Nature Energy on Feb. 18, bismuth vanadate electrodes with more bismuth on the surface (relative to vanadium) generate higher amounts of electrical current when they absorb energy from sunlight. This photocurrent drives the chemical reactions that split water into oxygen and hydrogen. The hydrogen can be stored for later use as a clean fuel. Producing only water when it recombines with oxygen to generate electricity in fuel cells, hydrogen could help us achieve a clean and sustainable energy future.

    “The surface termination modifies the system’s interfacial energetics, or how the top layer interacts with the bulk,” said co-corresponding author Mingzhao Liu, a staff scientist in the Interface Science and Catalysis Group of the Center for Functional Nanomaterials (CFN)[below], a U.S. Department of Energy (DOE) Office of Science User Facility at Brookhaven National Laboratory. “A bismuth-terminated surface exhibits a photocurrent that is 50-percent higher than a vanadium-terminated one.”

    “Studying the effects of surface modification with an atomic-level understanding of their origins is extremely challenging, and it requires tightly integrated experimental and theoretical investigations,” said co-corresponding author Giulia Galli from the University of Chicago(US) and DOE’s Argonne National Laboratory(US).


    “It also requires the preparation of high-quality samples with well-defined surfaces and methods to probe the surfaces independently from the bulk,” added co-corresponding author Kyoung-Shin Choi from the University of Wisconsin–Madison(US).

    Choi and Galli, experimental and theoretical leaders in the field of solar fuels, respectively, have been collaborating for several years to design and optimize photoelectrodes for producing solar fuels. Recently, they set out to design strategies to illuminate the effects of electrode surface composition, and, as CFN users, they teamed up with Liu.

    “The combination of expertise from the Choi Group in photoelectrochemistry, the Galli Group in theory and computation, and the CFN in material synthesis and characterization was vital to the study’s success,” commented Liu.

    Bismuth vanadate is a promising electrode material for solar water splitting because it strongly absorbs sunlight across a range of wavelengths and remains relatively stable in water. Over the past few years, Liu has perfected a method for precisely growing single-crystalline thin films of this material. High-energy laser pulses strike the surface of polycrystalline bismuth vanadate inside a vacuum chamber. The heat from the laser causes the atoms to evaporate and land on the surface of a base material (substrate) to form a thin film.

    “To see how different surface terminations affect photoelectrochemical activity, you need to be able to prepare crystalline electrodes with the same orientation and bulk composition,” explained co-author Chenyu Zhou, a graduate researcher from Stony Brook University working with Liu. “You want to compare apples to apples.”

    As grown, bismuth vanadate has an almost one-to-one ratio of bismuth to vanadium on the surface, with slightly more vanadium. To create a bismuth-rich surface, the scientists placed one sample in a solution of sodium hydroxide, a strong base.

    “Vanadium atoms have a high tendency to be stripped from the surface by this basic solution,” said first author Dongho Lee, a graduate researcher working with Choi. “We optimized the base concentration and sample immersion time to remove only the surface vanadium atoms.”

    To confirm that this chemical treatment changed the composition of the top surface layer, the scientists turned to low-energy ion scattering spectroscopy (LEIS) and scanning tunneling microscopy (STM) at the CFN.

    In LEIS, electrically charged atoms with low energy—in this case, helium—are directed at the sample. When the helium ions hit the sample surface, they become scattered in a characteristic pattern depending on which atoms are present at the very top. According to the team’s LEIS analysis, the treated surface contained almost entirely bismuth, with an 80-to-20 ratio of bismuth to vanadium.

    “Other techniques such as x-ray photoelectron spectroscopy can also tell you what atoms are on the surface, but the signals come from several layers of the surface,” explained Liu. “That’s why LEIS was so critical in this study—it allowed us to probe only the first layer of surface atoms.”

    In STM, an electrically conductive tip is scanned very close to the sample surface while the tunneling current flowing between the tip and sample is measured. By combining these measurements, scientists can map the electron density—how electrons are arranged in space—of surface atoms. Comparing the STM images before and after treatment, the team found a clear difference in the patterns of atomic arrangements corresponding to vanadium- and bismuth-rich surfaces, respectively.

    2
    The multiprobe surface analysis system in the CFN Proximal Probes Facility.

    “Combining STM and LEIS allowed us to identify the atomic structure and chemical elements on the topmost surface layer of this photoelectrode material,” said co-author Xiao Tong, a staff scientist in the CFN Interface Science and Catalysis Group and manager of the multiprobe surface analysis system used in the experiments. “These experiments demonstrate the power of this system for exploring surface-dominated structure-property relationships in fundamental research applications.”

    Simulated STM images based on surface structural models derived from first-principle calculations (those based on the fundamental laws of physics) closely matched the experimental results.

    “Our first-principle calculations provided a wealth of information, including the electronic properties of the surface and the exact positions of the atoms,” said co-author and Galli Group postdoctoral fellow Wennie Wang. “This information was critical to interpreting the experimental results.”

    After proving that the chemical treatment successfully altered the first layer of atoms, the team compared the light-induced electrochemical behavior of the treated and nontreated samples.

    “Our experimental and computational results both indicated that the bismuth-rich surfaces lead to more favorable surface energetics and improved photoelectrochemical properties for water splitting,” said Choi. “Moreover, these surfaces pushed the photovoltage to a higher value.”

    Many times, particles of light (photons) do not provide enough energy for water splitting, so an external voltage is needed to help perform the chemistry. From an energy-efficiency perspective, you want to apply as little additional electricity as possible.

    “When bismuth vanadate absorbs light, it generates electrons and electron vacancies called holes,” said Liu. “Both of these charge carriers need to have enough energy to do the necessary chemistry for the water-splitting reaction: holes to oxidize water into oxygen gas, and electrons to reduce water into hydrogen gas. While the holes have more than enough energy, the electrons don’t. What we found is that the bismuth-terminated surface lifts the electrons to higher energy, making the reaction easier.”

    Because holes can easily recombine with electrons instead of being transferred to water, the team did additional experiments to understand the direct effect of surface terminations on photoelectrochemical properties. They measured the photocurrent of both samples for sulfite oxidation. Sulfite, a compound of sulfur and oxygen, is a “hole scavenger,” meaning it quickly accepts holes before they have a chance to recombine with electrons. In these experiments, the bismuth-terminated surfaces also increased the amount of generated photocurrent.

    “It’s important that electrode surfaces perform this chemistry as quickly as possible,” said Liu. “Next, we’ll be exploring how co-catalysts applied on top of the bismuth-rich surfaces can help expedite the delivery of holes to water.”

    The work by Choi and Galli was supported by the National Science Foundation and used computational resources of the University of Chicago’s Research Computing Center. The work at the CFN was supported by the DOE Office of Science and carried out in the Materials Synthesis and Characterization and Proximal Probes Facilities.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Brookhaven Campus.


    BNL Center for Functional Nanomaterials.

    BNL NSLS-II.


    BNL NSLS II.


    BNL RHIC Campus.

    BNL/RHIC Star Detector.

    BNL/RHIC Phenix.

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE)(US), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.

     
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