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  • richardmitnick 5:21 pm on July 18, 2020 Permalink | Reply
    Tags: A new proposed experiment called FerMINI., , FNAL, , , The search for millicharged particles in the MeV/c2 to few GeV/c2 mass range.   

    From Fermi National Accelerator Lab: “Searching for millicharged particles” 

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    From Fermi National Accelerator Lab , an enduring source of strength for the US contribution to scientific research world wide.

    July 17, 2020
    Yu-Dai Tsai

    [I am in the hospital and copy/paste for images is not working (Thankyou RWJ Barnabas Robert Wood Johnson Hospital. See the full article for images. All images which show are a part of the .html template I have built for the institution.)

    Ever since Robert Millikan’s 1909 discovery of electric charge and, later, the discovery of the quark, scientists have postulated electric charge to come in discrete units, and the minimal electric charge has been believed to be carried by quarks. Yet theories still postulate that particles can carry much smaller charges — significantly smaller than that of quarks.

    Scientists, including Fermilab researchers, have proposed a new experiment to help search for these “millicharged particles.” The proposal is inspired by analyses based on results from several neutrino experiments. The potential discovery would shatter the current Standard Model paradigm and open a window to new physics.

    The new proposed experiment is called FerMINI [https://arxiv.org/abs/1812.03998] which has the ability to search for millicharged particles in the MeV/c2 to few GeV/c2 mass range.

    FerMINI builds on previous analyses [https://inspirehep.net/literature/1708533]. A group of theoretical physicists showed that data from neutrino experiments MiniBooNE at Fermilab, the Liquid Scintillator Neutrino Detector at Los Alamos National Laboratory, and Super-Kamiokande Observatory in Japan limits the possible range of mass and electric charge that millicharged particles can have. Their findings narrow the region where scientists should look for millicharged particles. Independent and detailed millicharge analyses were studied for the ArgoNeuT neutrino experiment and conducted by the ArgoNeuT collaboration.

    The search could extend beyond MiniBooNE and LSND to other Fermilab neutrino experiments, including MicroBooNE and the Short-Baseline Near Detector. Further, experiments such as the international, Fermilab-hosted Deep Underground Neutrino Experiment, or DUNE, and CERN’s proposed experiment, the Search for Hidden Particles, called SHiP, have the potential to discover millicharged particles in mass ranges that have yet to be experimentally tested. This research may have implications for their detector designs and analysis techniques.

    The FerMINI detector can sense millicharged particles produced in the Fermilab proton beam when it hits a fixed target. It detects multiple scintillation hits in a small time window as the millicharged-particle signature. The detector technology is inspired by the milliQan experiment, a proposed search at the Large Hadron Collider at CERN, some of whose collaborators are also involved in the FerMINI project.

    The search could potentially help explain the nature of dark matter, as the hypothetical particle could contribute to a fraction of the universe’s dark matter abundance. For example, scientists on the Experiment to Detect the Global EoR Signature, or EDGES, recently reported an anomaly in the 21-centimeter hydrogen absorption spectrum from the early universe. The discovery of millicharged particles as a fraction of dark matter might explain the anomaly.

    This type of fractional dark matter candidate, with sizable coupling to Standard Model particles, would be hard for underground direct-detection experiments to detect, because the dark matter particles would lose their kinetic energy through their interaction with Earth’s atmosphere and crust before they reach the underground detectors. The Fermilab experiments thus have advantages in detecting such particles since they can directly produce these particles from the proton beam with a high energy.

    We now know where we can look in searching for these millicharged particles, given available capabilities. By combining detector technology with existing and planned high-intensity proton beams provided by Fermilab, we can advance our search for these mysterious particles, overturning our understanding of the structure of nature’s fundamental constituents.

    The FerMINI collaboration, based at Fermilab, comprises 10 institutions.

    This work is supported by the DOE Office of Science.

    See the full here.


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    Please help promote STEM in your local schools.

    Stem Education Coalition

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    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 1:04 pm on June 22, 2020 Permalink | Reply
    Tags: "CMS collaboration publishes 1000th paper", , , CMS became the first experiment in the history of HEP to reach this outstanding total of papers., FNAL, , , , ,   

    From Fermi National Accelerator Lab: “CMS collaboration publishes 1,000th paper” 

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    From Fermi National Accelerator Lab , an enduring source of strength for the US contribution to scientific research world wide.

    June 22, 2020
    Boaz Klima

    We are proud to share with you the exciting news that on Friday, June 19, CMS reached a momentous milestone by submitting its 1,000th paper for publication [Physical Review Letters]. In doing so, CMS became the first experiment in the history of HEP to reach this outstanding total of papers.

    CERN/CMS Detector

    The very first paper published by the CMS collaboration as a whole was a description of the detector, submitted early in 2008. This was followed in 2009 by a series of papers describing the preoperation tuning of the apparatus using cosmic rays. The first publications of physics results based on LHC collisions appeared very soon after the LHC commenced operation at the end of 2009, and they have been issued at an average rate of about 100 papers per year since then. The publications timeline of collider-data papers split by physics topics is available on the CMS publications webpage.

    The scientific impact of CMS publications has been at the highest level. Approximately a third are published as letters in Physical Review Letters or Physics Letters B, where the standards for significance and timeliness are even more stringent than those required for longer articles. Indeed, several CMS letters have been singled out for special recognition as “Editor’s Selection,” a testament to the utmost importance of those results.

    By happy coincidence, the 1,000th CMS paper has been submitted close to the eighth anniversary of the most notable paper submitted so far, that reporting the observation of the Higgs boson, paper number 183, which was submitted in July 2012. The discovery of the Higgs boson led to a Nobel Prize.

    Not only has the number of papers produced by CMS reached an unprecedented level, but the diversity of physics topics covered is also unparalleled. Just one decade ago the high-energy physics field exploited three different types of accelerators to pursue separately research at the energy frontier, the intensity frontier and on heavy-ion collisions under extreme conditions. In contrast, the advanced design of the CMS detector, made possible by a long program of R&D, and the remarkable flexibility of the LHC accelerator, have enabled CMS to publish world-class results probing all three boundaries of knowledge.

    The exceptional success of CMS is a testimony to the skill and dedication of the collaboration, and credit for reaching the milestone of 1,000 publications belongs to all its members.

    See the full here.


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    FNAL Icon

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 12:42 pm on June 22, 2020 Permalink | Reply
    Tags: "Interview with Nobel laureate Carlo Rubbia about neutrino research" Video, , FNAL, ,   

    From Fermi National Accelerator Lab: “Interview with Nobel laureate Carlo Rubbia about neutrino research” Video 

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    FNAL Art Image by Angela Gonzales

    From Fermi National Accelerator Lab , an enduring source of strength for the US contribution to scientific research world wide.

    In this 5-minute video, Nobel laureate Carlo Rubbia explains why mysterious particles called neutrinos could be the key to understanding the nature of the universe. He talks about the search for a fourth type of neutrino and why the universe would not exist without neutrinos. He describes how scientists aim to unveil the secrets of the neutrino with the ICARUS (https://icarus.fnal.gov) and DUNE (https://fnal.gov/dune) neutrino experiments, hosted by Fermilab (https://fnal.gov). He recalls why early in his career he chose liquid argon as his material of choice to collect information about neutrino interactions with matter.

    FNAL/ICARUS

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

    See the full here.


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    FNAL Icon

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 1:01 pm on June 20, 2020 Permalink | Reply
    Tags: "Silicon detector R&D for future high-energy physics experiments", , , FNAL, , , ,   

    From Fermi National Accelerator Lab: “Silicon detector R&D for future high-energy physics experiments” 

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    From Fermi National Accelerator Lab , an enduring source of strength for the US contribution to scientific research world wide.

    June 19, 2020
    Ron Lipton

    Our ability to explore the physics of elementary particles depends on the sensors we use to translate flows of energy from particle collisions in our accelerators into electronic pulses in our detectors. The patterns of these pulses are used to reconstruct the underlying particles and their interactions. At the core of the mammoth detector assemblies and snugly surrounding the beam pipes are arrays of silicon sensors. These sensors, derived from integrated circuit technology, provide detailed patterns of interactions to micron-level (40 millionths of an inch) precision, with subnanosecond timing and low mass. The active area of these arrays has increased from a few square centimeters in experiments in the 1980s to 200 square meters in the CMS and ATLAS trackers at the Large Hadron Collider at CERN.

    CERN/CMS Detector

    CERN ATLAS Credit CERN SCIENCE PHOTO LIBRARY

    The CMS high-granularity calorimeter, or HGCal, will use 600 square meters of silicon. The precision of these detectors enables unique identification of heavy quarks (bottom and charm) that travel a fraction of a millimeter before they decay. The precision was crucial, for example, in the discoveries of the top quark in 1995, CP violation and mixing in the B meson system, and the Higgs boson in 2012.

    Research and development to improve the characteristics and develop better silicon detectors with the use of new technologies continue as we upgrade the existing detectors for better performance and develop designs for experiments at future generations of accelerators.

    1
    Working with collaborating laboratories and industrial partners, Fermilab researchers have developed and demonstrated the first three-layer 3-D bonded devices. This shows a three-layer 3-D chip stack. Image courtesy of Ron Lipton

    The 3-D integration of pixelated sensors with readout chips was an infant technology when we began R&D in 2006. The 3-D interconnection technique (now called hybrid bonding by the semiconductor industry) can replace the large, costly, solder bump interconnect technology with one that can be directly integrated into semiconductor process lines. It reduces the minimum spacing between pixels from about 50 microns to three, allows multilayer stacked connections through the body of the semiconductor, and dramatically reduces the capacitance of the interconnect, increasing speed and reducing electronic noise. Working with collaborating laboratories and industrial partners, we have developed and demonstrated the first three-layer 3-D bonded devices, with two electronics layers occupying only 35 microns in height, down from the usual hundreds. This hybrid bonding technology is now probably in your smart phone camera.

    2
    Schematic of the stacked layers. Image courtesy of Ron Lipton

    Future accelerators, including the High-Luminosity LHC, will produce collisions at a rate many times higher than the current LHC. The complexity of these collision events puts a premium on fast timing and recognition of very complex patterns of energy deposited in detectors. A possibility we are exploring is the induced-current detector. 3-D technology allows us to combine small pixels and low electronic noise with sophisticated electronics. The sensitivity and timing capabilities are now so good that we can measure the detailed shape of pulses due to charge movement deep in the silicon. This pattern of pulse shapes can give us much more information than the usual measurement of only the total charge. If this idea works, a single layer of silicon could measure timing to picoseconds, position to microns, as well as track angle, compressing multiple layers of sensor into one. This would greatly increase the power of detectors to select and process interesting events at very high speed. Work is under way on simulations of these effects and collaboration with industry on a 3-D demonstrator.

    Another way to address the experimental challenges is to improve the time resolution of silicon detectors. This can be done by designing the silicon to provide internal gain, providing a larger signal with a faster rise time. The low-gain avalanche diode, or LGAD, was designed to accomplish this. The LGAD is a new technology, and improved variants are continually emerging. Fermilab has an extensive program of testing and qualifying these LGAD detectors in bench tests and in the Fermilab Test Beam. The work is a close collaboration with the foundries and with other institutes within CMS and ATLAS. This program has been crucial in the validation and adoption of LGAD technology for the CMS upgrade endcap timing layer.

    The current generation of LGADs suffers from dead regions at the edges of each pixel and has only moderate radiation hardness. This limits the pixel size and range of applicability of these devices. By changing the top layers of the sensors (AC coupling) and adding a layer buried below the surface (buried gain layer) we can both eliminate most of the dead region and provide for a more well-defined gain that is also more resistant to radiation. First demonstrators are now being fabricated in collaboration with industry and universities.

    3
    Researchers are developing 8-inch sensors, seen here on a probe station at SiDet, for the CMS HGCal. Photo courtesy of Ron Lipton

    Finally, the very large area of the CMS HGCal prompted us to begin the development of large-area sensors, producing the first HEP sensors on 8-inch silicon wafers in collaboration with industry. We developed the process flow with colleagues from other laboratories and integrated designs from contributors all over the world. We have demonstrated high quality 8-inch sensors thinned to 200 microns.

    In this work, intense collaboration with the Fermilab ASIC group, support from CMS and DOE, infrastructure at SiDet, strong collaboration with laboratory, university and industrial partners, and the central contributions of summer students, graduate students, and postdocs have all been vital. These are all exciting developments and there is much more to do. As Richard Feynman said: “There is plenty of room at the bottom.”

    See the full here.


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    FNAL Icon

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 2:36 pm on June 11, 2020 Permalink | Reply
    Tags: , FNAL, Muon g-2 experiment, , Scientists studying the muon have been puzzled by a strange pattern in the way muons rotate in magnetic fields., This week an international team of more than 170 physicists published the most reliable prediction so far for the theoretical value of the muon’s anomalous magnetic moment.   

    From Fermi National Accelerator Lab: “Physicists publish worldwide consensus of muon magnetic moment calculation” 

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    FNAL Art Image by Angela Gonzales

    From Fermi National Accelerator Lab , an enduring source of strength for the US contribution to scientific research world wide.

    June 11, 2020
    Jerald Pinson

    For decades, scientists studying the muon have been puzzled by a strange pattern in the way muons rotate in magnetic fields, one that left physicists wondering if it can be explained by the Standard Model — the best tool physicists have to understand the universe.

    This week, an international team of more than 170 physicists published the most reliable prediction so far for the theoretical value of the muon’s anomalous magnetic moment, which would account for its particular rotation, or precession. The magnetic moment of subatomic particles is generally expressed in terms of the dimensionless Landé factor, called g. While a number of international groups have worked separately on the calculation, this publication marks the first time the global theoretical physics community has come together to publish a consensus value for the muon’s magnetic moment [ https://arxiv.org/abs/2006.04822 ].

    The result differs from the most recent experimental measurement, which was performed at Brookhaven National Laboratory in 2004, but not significantly enough to unambiguously answer this question.

    Now the world awaits the result from Fermilab’s current Muon g-2 experiment. In the upcoming months, physicists working on the experiment will unveil their preliminary measurement for the value. Depending on how much the Standard Model theoretical calculation differs from the upcoming experimental measurement, physicists may be one step closer to determining whether the muon’s magnetic interactions are hinting at particles or forces that have yet to be discovered.

    1
    Today’s publication by the Muon g-2 Theory Initiative marks the first time the global theoretical physics community has come together to publish a consensus value for the muon’s magnetic moment. Now the world awaits the result from Fermilab’s current Muon g-2 experiment, whose magnetic storage ring is pictured here. Photo: Reidar Hahn, Fermilab.

    In the late 1960s at CERN laboratory, scientists began using a large circular magnetic ring to test the theory that described how muons should “wobble” when moving through a magnetic field. Since then, experimenters have continued to quantify that wobble, making more and more precise measurements of the muon’s anomalous magnetic moment.

    The decades-long effort eventually led to an experiment at Brookhaven National Laboratory and its successor at Fermilab, as well as plans for a new experiment in Japan. At the same time, theorists worked to improve the precision of their calculations and fine-tune their predictions.

    The theoretical value of the anomalous magnetic moment of the muon, published today, is:

    a = (g-2)/2 (muon, theory) = 116 591 810(43) x 10-12

    The most precise experimental result available so far is:

    a = (g-2)/2 (muon, expmt) = 116 592 089(63) x 10-12

    Again, the slight discrepancy between the experimental measurements and the predicted value has persisted, and again it is just beneath the threshold to make a definitive statement.

    This theoretical value, published in the arXiv [above], is the result of over three years of work by 130 physicists from 78 institutions in 21 countries.

    “We’ve not had a theory effort like this before in which all the different evaluations are combined into a single Standard Model prediction,” said Aida El-Khadra, a physicist at the University of Illinois and co-chair of the Steering Committee for the Muon g-2 Theory Initiative, the name of the group of scientists who worked on the calculation.

    Their work builds on a single equation published in 1928 that simultaneously started the field of quantum electrodynamics and laid the foundations for the Muon g-2 experiment.

    An elegant theory

    If you were to ask physicists what they considered the most accurate and successful equation in their field, chances are more than a few would say it’s Dirac’s equation, which describes the relativistic quantum theory of the electron. Published in 1928, Dirac described the spin motion of electrons, and his equation bridged the gap between Einstein’s theory of relativity and the theory of quantum mechanics, and unintentionally predicted the existence of antimatter with only a single equation.

    Dirac was also able to calculate something called the magnetic moment of the electron, which he described as being “an unexpected bonus.”

    Electrons can be thought of as tiny spinning tops that rotate on their axis, an intrinsic property that makes each electron act like a tiny magnet. When placed in a magnetic field, such as the ones generated in particle accelerators, electrons will precess — or wobble on their axis — in a specific and predictable pattern. This wobble is an effect of the particle’s magnetic moment, and it applies to more than electrons. Every electrically charged particle with ½ spin (spin is quantified in half units) behaves in the same way, including particles called muons, which have the same properties as electrons but are more than 200 times as massive.

    Dirac’s equation, which did not take into account the effects of quantum fluctuations, predicted that g would equal 2. Experiment has shown that the actual value differs from that simple expectation — hence the name “muon g-2.”

    Physicists now have a much better understanding of what those quantum fluctuations are and how they behave at subatomic scales, but precisely calculating how they affect the muon’s path is no easy task.

    “Calculating the effects of these quantum fluctuations at the precision level demanded by modern experiment isn’t something that one brilliant person can do alone,” El-Khadra said. “It really takes the whole village.”

    Meeting of the minds

    With so many physicists working on the latest developments to the theory around the world, El-Khadra and her colleagues at Fermilab knew the best way to facilitate interactions between the groups was to bring them all together. So, starting in 2016, El-Khadra and her colleagues in the Fermilab Theory Group, together with Brookhaven National Laboratory scientist Christoph Lehner, Theory Initiative co-chair, and several other international collaborators reached out to the leaders in the global community of physicists working on this problem to put together a new initiative, the Muon g-2 Theory Initiative. The initiative, led by a nine-person Steering Committee that includes leaders of all the major efforts in both theory and experiment, organized a series of workshops around the world, including in the U.S., Japan and Germany, the first of which was hosted at Fermilab in 2017.

    “We had some very intense discussions,” El-Khadra said, “That led to more detailed comparisons and a better understanding of the pros and cons of the various approaches.”

    The establishment of the Muon g-2 Theory Initiative was the first coherent international effort to bring together all of the parties working on the Standard Model value of the muon’s anomalous magnetic moment.

    “Before this initiative began, there were a number of evaluations in the literature of the Standard Model value, each of which differed slightly from the others,” said Boston University scientist Lee Roberts, co-founder of the Fermilab experiment and a member of the initiative’s Steering Committee. “The remarkable thing is that this worldwide community was able to come together and to agree on the ‘best’ value for each of the contributions to the value of the muon’s magnetic moment.”

    2
    Standard Model theory: The chart on the left shows the contributions to the value of the anomalous magnetic moment from the Standard Model of particles and interactions. About 99.994% comes from contributions due to the electromagnetic force while the hadronic contributions account for only 0.006% (note the blue sliver). The right chart shows the contributions to the total uncertainty in the theoretical prediction. About 99.95% of the total error in the theoretical prediction is due the uncertainties in the hadronic corrections, while, at about 0.05% of the total error, the uncertainties in the electromagnetic and electroweak contributions are negligibly small. (QED – quantum electrodynamic forces; EW – electroweak forces; HVP – hadronic vacuum polarization; HLbL – hadronic light-by-light). Image: Muon g-2 Theory Initiative.

    Quantum calculations

    “Muons and other spin-½ particles are never really alone in the universe,” said Fermilab scientist Chris Polly, who is one of Muon g-2’s spokespersons, along with University of Manchester physicist Mark Lancaster. “They interact with a whole entourage of particles that are constantly popping into and out of existence.”

    The two main sources of uncertainty are hadronic vacuum polarization and light-by-light scattering — in which a muon emits and reabsorbs photons after they have traveled through a bubble of quarks and gluons. Both of these factors combine to make up less than 0.01% of the effect on the muon’s wobble yet make up the main source of uncertainty in the theory calculation.

    Calculating the light-by-light scattering part of the hadronic contribution has proven to be especially difficult, and before the start of the Muon g-2 Theory Initiative, physicists had not yet produced reliable estimates of its effects. The best they could manage were rough approximations that led some to wonder whether these evaluations of the light-by-light scattering might be the source of the difference between the muon’s calculated anomalous magnetic moment and the experimentally measured value.

    But theorists are now confident that they can lay these doubts to rest. Thanks to heroic efforts in recent years within the theory community, not just one, but two independent evaluations are now available, each with reliably estimated uncertainties, which are included in the total error of the Standard Model prediction listed above.

    “We’ve now quantified the light-by-light scattering contribution to the extent that it can no longer be used as an explanation to save the Standard Model if the experimental value turns out to differ significantly from the theoretical prediction,” said Brookhaven National Laboratory physicist Christoph Lehner, Theory Initiative co-chair.

    And with so much riding on the line, El-Khadra and other members of the Theory Initiative have left nothing to chance.

    “We have strongly emphasized the importance of including evaluations based on several different methods in our construction of the Standard Model prediction of the anomalous magnetic moment of the muon,” El-Khadra said. “Because if we find that the Fermilab experiment’s measurement is inconsistent with the Standard Model, we want to be sure.”

    The Fermilab Muon g-2 experiment is supported by the DOE Office of Science.

    See the full here.


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    FNAL Icon

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 12:57 pm on June 3, 2020 Permalink | Reply
    Tags: , FNAL, , SENSEI collaboration   

    From Fermi National Accelerator Lab: “SENSEI gets quiet” 

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    FNAL Art Image by Angela Gonzales

    From Fermi National Accelerator Lab , an enduring source of strength for the US contribution to scientific research world wide.

    June 3, 2020
    Sho Uemura

    What makes for a good dark matter detector? It has a lot in common with a good teleconference setup: You need a sensitive microphone and a quiet room.

    Scientists working on the SENSEI experiment at the Department of Energy’s Fermilab now have demonstrated for the first time a particle detector — based on charge-coupled device, or CCD, technology — with both the sensitivity and reduced background rates needed for an effective search for low-mass particles of dark matter, the mysterious substance that accounts for about 80 percent of all matter in the universe.

    1
    This picture shows the the new SENSEI skipper-CCD module. Image: SENSEI collaboration.

    The demonstration is important in two ways. First, the background rates measured by the SENSEI detector are record lows for a silicon detector. They set the world’s strongest limits on dark matter interactions with electrons, across a wide range of models. Second, it shows the high quality of the detectors that will be used in the full-scale SENSEI experiment under construction. SENSEI will run at the Canadian SNOLAB deep underground laboratory.

    SNOLAB, a Canadian underground physics laboratory at a depth of 2 km in Vale’s Creighton nickel mine in Sudbury, Ontario

    The SENSEI detector is a 5.4-megapixel CCD made of 2 grams of silicon currently operating about 100 meters underground at Fermilab. If a dark matter particle collides with one of the electrons in the silicon, the energy transferred to the electron may be enough to liberate it from the crystal structure of the silicon. If there is enough energy, additional electrons will be freed. This charge is the signal SENSEI scientists are looking for. The smaller the signal SENSEI can detect, the broader the range of dark matter models it can test.

    3
    This shows the SENSEI CCD module in the detector vessel. Photo: SENSEI collaboration.

    To observe small dark matter signals, the first thing scientists need is a sensitive detector. In other words, they must be able to detect a small signal and consistently distinguish it from a truly empty detector. As demonstrated in previous work, SENSEI’s skipper-CCDs, designed by Lawrence Berkeley National Laboratory, can count the exact number of electrons in each pixel.

    4
    In this test data, taken with a very long acquisition time, we plotted the measured charge in each pixel. The true charge is of course always an integer number of electrons. The measurement precision is a small fraction of an electron, so the 0-electron and 1-electron pixels are well separated, and there is no possibility of miscategorizing an empty pixel. Image: SENSEI collaboration.

    Second, scientists need low background — the rate of signal-like events from causes other than dark matter has to be small. A sensitive detector with high background is like a studio microphone in a noisy room. Even if the microphone can pick up a whisper, your soft voice might be drowned out by the noise of the washing machine in the background. The only way to improve the recording is to eliminate the noise of the washing machine.

    The SENSEI collaboration now has demonstrated for the first time that it has a sensitive dark matter detector and can reduce background rates. It’s important to demonstrate that a detector can achieve low background rates before you scale up to a larger experiment with the same technology, because otherwise you are just going to scale up your background rate. Previous dark matter searches by SENSEI used prototype CCDs, which had high sensitivity but also high backgrounds because they were not made with the highest-quality silicon.

    5
    SENSEI rules out the blue regions, where the rate of dark matter interactions would be larger than the event rate that SENSEI observes.
    Gray regions are ruled out by other experiments. The orange bands are favored by theoretical models and are targets for the full-scale SENSEI experiment. Image: SENSEI collaboration.

    SENSEI’s new dark matter search has yielded the first result from its new science-grade CCDs, which were fabricated in a dedicated production run for SENSEI with high-quality silicon. The collaboration also reduced the amount of radiation that hits the CCD by adding extra shielding around the experiment. The result was a decrease in background event rates compared to the previous search with a prototype CCD. The rate of single-electron events decreased from 33,000 to 450 events/gram-day, and we see fewer two-electron events (five, down from 21) in a much larger exposure (2.09 gram-days, up from 0.043). We also see no three- or four-electron events — just as in the previous search, but with a larger exposure.

    The science-grade CCDs work as well as could have been hoped, and SENSEI expects background rates to be even lower at SNOLAB. There will likely be more great science from SENSEI in the near future!

    Learn more from SENSEI’s preprint or the collaboration’s presentation at a seminar at Fermilab.

    See the full here.


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    FNAL Icon

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 11:40 am on May 12, 2020 Permalink | Reply
    Tags: "Why DUNE? Searching for the origin of matter", , FNAL, , ,   

    From Sanford Underground Research Facility: “Why DUNE? Searching for the origin of matter” 

    SURF logo

    From Sanford Underground Research Facility


    Homestake Mining Company

    May 11, 2020
    Erin Lorraine Broberg

    1
    DUNE science goal icon: Origin of matter.Credit: Fermilab

    Why does matter exist? It may seem like a strange question, but according to current models of the early universe, matter shouldn’t exist.

    “According to what we know about the laws of physics, the amount of matter in the universe should be, effectively, zero,” said André de Gouvêa, a theoretical physicist with the DUNE collaboration and professor at Northwestern University.

    In physics, the discrepancy between what we see—a universe filled with galaxies and a planet teeming with life—and what models predict we should see—absolutely nothing—is called the “matter-antimatter asymmetry problem.” The international Deep Underground Neutrino Experiment, or DUNE, hosted by the Department of Energy’s Fermilab and to be built at Fermilab and Sanford Lab, seeks to solve this problem, which has dogged physicists for nearly a century.

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


    The Deep Underground Neutrino Experiment will measure neutrino oscillations by studying a neutrino that will be sent from Fermilab to the DUNE detectors at the Sanford Underground Neutrino Facility. The experiment will use a muon neutrino beam created at Fermilab’s Long-Baseline Neutrino Facility and send it 800 miles/1300 kilometers straight through the earth to South Dakota. By the time the neutrinos arrive in South Dakota, only a small fraction of neutrinos will be detected as muon neutrinos. Most neutrinos will interact as electron and tau neutrinos. Graphic courtesy Fermilab

    A universe-sized problem

    Despite what the models predict, we find ourselves amidst a universe replete with matter. Everything we see around us is made from just a few types of fundamental particles. Combined, they form protons and neutrons which join up with electrons to form atoms, which in turn bind to make molecules, building ever larger.

    But these key ingredients are only half the story.

    In the 1930s, physicists discovered “antiparticles” that mirror the fundamental particles. Identical in nearly every way, except with reversed charge, these equal yet opposite particles are called antimatter. Just like matter particles, antimatter particles could combine to build bigger and bigger units of antimatter—if they ever survived long enough do to so.

    Although matter and antimatter particles are nearly indistinguishable, the two forms do not coexist peacefully. When antimatter comes into contact with regular matter, particles and antiparticles immediately annihilate, leaving leaving pure energy in their wake.

    This complete, mutual annihilation is the impetus of the matter-antimatter asymmetry problem. Our current models dictate that the Big Bang created equal parts matter and antimatter. Within a second, all the matter and antimatter should have met and annihilated, leaving behind a universe with nothing but energy in the form of light.

    2
    Identical in nearly every way, except with reversed charge, these equal yet opposite particles are called antimatter. Graphic courtesy Fermilab

    “The problem is, if we take our favorite model and calculate the evolution of the universe, we get a prediction that is completely off,” de Gouvêa said. “There should not be any matter in the universe we live in today.”

    We know, of course, that this didn’t happen. We live in a matter-dominated universe with swirling galaxies, innumerable stars and at least one life-sustaining planet. Somehow, about one billionth of the total amount of matter created in the Big Bang managed to evade annihilation and fill the universe with the matter we see today. Thus, the matter-antimatter asymmetry problem.

    Physicists believe there is an undiscovered mechanism, hidden in the wrinkles of nature’s laws, that gave matter an initial advantage over antimatter. And for nearly a century, they’ve been trying to pinpoint it.

    A crack in nature’s symmetry

    Because matter and antimatter are mirror images of each other, physicists assumed that the laws of nature applied to both matter particles and antimatter particles in the exact same way. In physics, this type of equality is called a “symmetry.”

    According to this idea, weak and strong forces should bind particles and antiparticles without discrimination. Gravity should pull on antimatter with the same force it exerts on matter. Magnets should attract oppositely charged particles and antiparticles with the same gusto. In fact, an entire universe made of antimatter should look identical to the one we live in today.

    This assumption of a perfect symmetry among the fundamental building blocks of the universe held true until the 1960s, when James Cronin and Val Fitch made the shocking discovery that, in a very specific case, the universe treats matter slightly different than antimatter.

    Their Nobel Prize-winning experiment examined the way that quarks (fundamental particles that make up protons and neutrons) and antiquarks (their corresponding antiparticles) interacted with the weak force. Rather than treating quarks and antiquarks the same way, the weak force favored quarks in an infamous violation of what is called the Charge Parity (CP) symmetry.

    In other words, the universe had revealed a slight preference for matter over antimatter.

    3
    CP violation experiment: In 1963, a beam from BNL’s Alternating Gradient Synchrotron and the pictured detectors salvaged from the Cosmotron were used to prove the violation of conjugation (C) and parity (P) – winning the Nobel Prize in physics for Princeton University physicists James Cronin and Val Fitch. Photo courtesy Brookhaven National Laboratory.

    This discovery stunned the particle physics community. In the decades that followed, researchers continued to make precision measurements of these decays, combing their data for new physics that might be lurking within this phenomenon. Thirty years after Cronin and Fitch’s discovery, Elizabeth Worcester was making such measurements at Fermilab’s Tevatron with the KTeV experiment.

    “In the 1990s, we were studying the same decays in which CP violation was first observed,” said Worcester, who is now a DUNE physcis co-coordinator and physicist at Brookhaven National Laboratory.

    This glitch in the laws of nature specifically caught the attention of physicists studying the imbalance of matter and antimatter in the universe. Was this violation of CP symmetry the mechanism that allowed some matter to escape annihilation after the Big Bang?

    Subsequent experiments combined with more and more sophisticated calculations demonstrated that nature’s unequal treatment of quarks and antiquarks is not quite big enough to account for the gaping discrepancy we see today.

    However, scientists think the existence of CP violation is a major clue.

    “This violation could mean there is something very fundamental about the laws of nature that we are missing,” de Gouvêa said.

    As soon as Cronin and Fitch made their discovery, physicists began to wonder if other fundamental particles broke the same symmetry. Perhaps multiple sources of CP violation, when combined, could explain how so much matter escaped annihilation in the early universe.

    By finding another, even bigger crack in this symmetry, physicists aim to prove that the universe has an overarching preference for matter, making our current universe possible.

    A ghost-like candidate

    If quarks didn’t provide enough CP violation in the early universe, could another category of elementary particles known as neutrinos have provided another way to favor matter over antimatter?

    “If you look at everything that we’ve learned about neutrinos so far, it indicates that CP could be violated in the neutrino sector,” de Gouvêa said. “There is no specific reason to expect it not to be violated.”

    Neutrinos are extremely challenging to work with. Trillions of these particles pass through you each second. Their miniscule mass and neutral charge make them almost impossible to detect. Building an experiment to test whether these ghost-like particles violate the CP symmetry is even more ambitious.

    “The reason we don’t know if neutrinos violate CP symmetry is purely an experimental issue,” said Ryan Patterson, DUNE physics co-coordinator and professor of physics at the California Institute of Technology (Caltech). “Neutrinos could violate CP a lot, but we don’t know yet because the experiments up to this point haven’t been sensitive enough.”

    One peculiar property of neutrinos, however, makes the DUNE experiment possible. As neutrinos speed through the universe just under the speed of light, they alternate between three different types, or flavors. This process is called oscillation.

    4
    As neutrinos speed through the universe just under the speed of light, they alternate between three different types, or flavors. This process is called oscillation. Graphic courtesy Fermilab

    “In regard to neutrinos, we only have one realistic way of measuring CP violation: it will show itself in the way neutrinos oscillate between flavors,” de Gouvêa said.

    In principle, the measurement is quite simple, according to de Gouvêa.

    “You simply compare a matter process with an antimatter process, and then you ask if they agree,” de Gouvêa said. To measure the CP violation, researchers must compare the oscillations of neutrinos with the oscillations of antineutrinos. If there is a discrepancy in the way they oscillate over a distance, then neutrinos break the symmetry.

    The difficult part of the experiment is that neutrino oscillations occur over hundreds of miles. To measure a deviation or discrepancy, researchers would need… well, they would need to build a long-baseline neutrino facility.

    Are neutrinos the reason we exist?

    The particulars of this universe-sized mystery have guided the design of the aptly named Long-Baseline Neutrino Facility (LBNF), which will house the Deep Underground Neutrino Experiment. Stretching across the Midwest, with infrastructure located at Fermilab in Batavia, Illinois and at Sanford Lab in Lead, South Dakota, the facility allows researchers to measure just how neutrinos and antineutrinos oscillate over long distances.

    It works like this: a particle accelerator will generate intense beams of neutrinos and antineutrinos at Fermilab. The beams will travel 800 miles straight through rock and earth – no tunnel needed – to enormous particle detectors located deep underground at Sanford Underground Research Facility (Sanford Lab), where 4,850 feet of rock overburden shield the detectors from unwanted background signals.

    During their trip through the Earth’s crust—which takes just four milliseconds—the neutrinos and antineutrinos will oscillate, changing from one flavor into another. Conveniently, the distance between Fermilab and Sanford Lab is ideal for this measurement; by the time the particles arrive at Sanford Lab, their oscillations will be at their peak.

    “To get the best measurement, we put the detectors right where we expect the oscillation to be maximal,” Patterson said.

    When the beam reaches Sanford Lab, some of the neutrinos and antineutrinos will collide with argon atoms inside the detectors. These collisions result in unique signals. By measuring and comparing hundreds of these signals, researchers will be able to tell if neutrinos and antineutrinos oscillate in different ways – the sure-tell sign of CP symmetry violation – and if so, by how much.

    “I think what the neutrinos are going to tell us could change our understanding of nature in a very interesting way,” de Gouvêa said.

    So, why DUNE? In a nutshell, it could help scientists answer one of the big unsolved questions in science and give all of us an answer to the reason we—and everything else in the universe—exists.

    That, however, is only part of the story. Stay tuned for part II of our series of stories about the science of DUNE.

    See the full article here .


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    About us.
    The Sanford Underground Research Facility in Lead, South Dakota, advances our understanding of the universe by providing laboratory space deep underground, where sensitive physics experiments can be shielded from cosmic radiation. Researchers at the Sanford Lab explore some of the most challenging questions facing 21st century physics, such as the origin of matter, the nature of dark matter and the properties of neutrinos. The facility also hosts experiments in other disciplines—including geology, biology and engineering.

    The Sanford Lab is located at the former Homestake gold mine, which was a physics landmark long before being converted into a dedicated science facility. Nuclear chemist Ray Davis earned a share of the Nobel Prize for Physics in 2002 for a solar neutrino experiment he installed 4,850 feet underground in the mine.

    Homestake closed in 2003, but the company donated the property to South Dakota in 2006 for use as an underground laboratory. That same year, philanthropist T. Denny Sanford donated $70 million to the project. The South Dakota Legislature also created the South Dakota Science and Technology Authority to operate the lab. The state Legislature has committed more than $40 million in state funds to the project, and South Dakota also obtained a $10 million Community Development Block Grant to help rehabilitate the facility.

    In 2007, after the National Science Foundation named Homestake as the preferred site for a proposed national Deep Underground Science and Engineering Laboratory (DUSEL), the South Dakota Science and Technology Authority (SDSTA) began reopening the former gold mine.

    In December 2010, the National Science Board decided not to fund further design of DUSEL. However, in 2011 the Department of Energy, through the Lawrence Berkeley National Laboratory, agreed to support ongoing science operations at Sanford Lab, while investigating how to use the underground research facility for other longer-term experiments. The SDSTA, which owns Sanford Lab, continues to operate the facility under that agreement with Berkeley Lab.

    The first two major physics experiments at the Sanford Lab are 4,850 feet underground in an area called the Davis Campus, named for the late Ray Davis. The Large Underground Xenon (LUX) experiment is housed in the same cavern excavated for Ray Davis’s experiment in the 1960s.

    LBNL LZ project at SURF, Lead, SD, USA, will replace LUX at SURF

    In October 2013, after an initial run of 80 days, LUX was determined to be the most sensitive detector yet to search for dark matter—a mysterious, yet-to-be-detected substance thought to be the most prevalent matter in the universe. The Majorana Demonstrator experiment, also on the 4850 Level, is searching for a rare phenomenon called “neutrinoless double-beta decay” that could reveal whether subatomic particles called neutrinos can be their own antiparticle. Detection of neutrinoless double-beta decay could help determine why matter prevailed over antimatter. The Majorana Demonstrator experiment is adjacent to the original Davis cavern.

    LUX’s mission was to scour the universe for WIMPs, vetoing all other signatures. It would continue to do just that for another three years before it was decommissioned in 2016.

    In the midst of the excitement over first results, the LUX collaboration was already casting its gaze forward. Planning for a next-generation dark matter experiment at Sanford Lab was already under way. Named LUX-ZEPLIN (LZ), the next-generation experiment would increase the sensitivity of LUX 100 times.

    SLAC physicist Tom Shutt, a previous co-spokesperson for LUX, said one goal of the experiment was to figure out how to build an even larger detector.
    “LZ will be a thousand times more sensitive than the LUX detector,” Shutt said. “It will just begin to see an irreducible background of neutrinos that may ultimately set the limit to our ability to measure dark matter.”
    We celebrate five years of LUX, and look into the steps being taken toward the much larger and far more sensitive experiment.

    Another major experiment, the Long Baseline Neutrino Experiment (LBNE)—a collaboration with Fermi National Accelerator Laboratory (Fermilab) and Sanford Lab, is in the preliminary design stages. The project got a major boost last year when Congress approved and the president signed an Omnibus Appropriations bill that will fund LBNE operations through FY 2014. Called the “next frontier of particle physics,” LBNE will follow neutrinos as they travel 800 miles through the earth, from FermiLab in Batavia, Ill., to Sanford Lab.

    FNAL LBNE/DUNE from FNAL to SURF, Lead, South Dakota, USA


    LBNE

    U Washington Majorana Demonstrator Experiment at SURF

    The MAJORANA DEMONSTRATOR will contain 40 kg of germanium; up to 30 kg will be enriched to 86% in 76Ge. The DEMONSTRATOR will be deployed deep underground in an ultra-low-background shielded environment in the Sanford Underground Research Facility (SURF) in Lead, SD. The goal of the DEMONSTRATOR is to determine whether a future 1-tonne experiment can achieve a background goal of one count per tonne-year in a 4-keV region of interest around the 76Ge 0νββ Q-value at 2039 keV. MAJORANA plans to collaborate with GERDA for a future tonne-scale 76Ge 0νββ search.

    CASPAR at SURF


    CASPAR is a low-energy particle accelerator that allows researchers to study processes that take place inside collapsing stars.

    The scientists are using space in the Sanford Underground Research Facility (SURF) in Lead, South Dakota, to work on a project called the Compact Accelerator System for Performing Astrophysical Research (CASPAR). CASPAR uses a low-energy particle accelerator that will allow researchers to mimic nuclear fusion reactions in stars. If successful, their findings could help complete our picture of how the elements in our universe are built. “Nuclear astrophysics is about what goes on inside the star, not outside of it,” said Dan Robertson, a Notre Dame assistant research professor of astrophysics working on CASPAR. “It is not observational, but experimental. The idea is to reproduce the stellar environment, to reproduce the reactions within a star.”

     
  • richardmitnick 1:53 pm on May 4, 2020 Permalink | Reply
    Tags: , Data onslaught, FNAL, , ,   

    From Fermi National Accelerator Lab: “DUNE prepares for data onslaught” 

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    From Fermi National Accelerator Lab , an enduring source of strength for the US contribution to scientific research world wide.

    May 4, 2020
    Jim Daley

    The international Deep Underground Neutrino Experiment, hosted by Fermilab, will be one of the most ambitious attempts ever made at understanding some of the most fundamental questions about our universe.

    LBNF/DUNE

    SURF-Sanford Underground Research Facility, Lead, South Dakota, USA


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


    SURF DUNE LBNF Caverns at Sanford Lab


    FNAL DUNE Argon tank at SURF

    Currently under construction at the Sanford Underground Research Facility in South Dakota, DUNE will provide a massive target for neutrinos. When it’s operational, DUNE will comprise around 70,000 tons of liquid argon — more than enough to fill a dozen Olympic-sized swimming pools — contained in cryogenic tanks nearly a mile underground.

    Neutrinos are ubiquitous. They were formed in the first seconds after the Big Bang, even before atoms could form, and they are constantly being produced by nuclear reactions in stars. When massive stars explode and become supernovae, the vast majority of the energy given off in the blast is released as a burst of neutrinos.

    In the laboratory, scientists use particle accelerators to make neutrinos. In DUNE’s case, Fermilab accelerators will generate the world’s most powerful high-energy neutrino beam, aiming it at the DUNE neutrino detector 800 miles (1,300 kilometers) away in South Dakota.

    When any of these neutrinos — star-born or terrestrial — strikes one of the argon atoms in the DUNE detector, a cascade of particles results. Every time this happens, billions of detector digits are generated, which must be saved and analyzed further by collaborators over the world. The resulting data that will be churned out by the detector will be immense. So, while construction continues in South Dakota, scientists around the world are hard at work developing the computing infrastructure necessary to handle the massive volumes of data the experiment will produce.

    3
    The goal of the DUNE Computing Consortium is to establish a global computing network that can handle the massive data dumps DUNE will produce by distributing them across the grid. Photo: Reidar Hahn, Fermilab

    The first step is ensuring that DUNE is connected to Fermilab with the kind of bandwidth that can carry tens of gigabits of data per second, said Liz Sexton-Kennedy, Fermilab’s chief information officer. As with other aspects of the collaboration, it requires “a well-integrated partnership,” she said. Each neutrino collision in the detector will produce an array of information to be analyzed.

    “When there’s a quantum interaction at the center of the detector, that event is physically separate from the next one that happens,” Sexton-Kennedy said. “And those two events can be processed in parallel. So, there has to be something that creates more independence in the computing workflow that can split up the work.”

    Sharing the load

    One way to approach this challenge is by distributing the workflow around the world. Mike Kirby of Fermilab and Andrew McNab of the University of Manchester in the UK are the technical leads of the DUNE Computing Consortium, a collective effort by members of the DUNE collaboration and computing experts at partner institutions. Their goal is to establish a global computing network that can handle the massive data dumps DUNE will produce by distributing them across the grid.

    “We’re trying to work out a roadmap for DUNE computing in the next 20 years that can do two things,” Kirby said. “One is an event data model,” which means figuring out how to handle the data the detector produces when a neutrino collision occurs, “and the second is coming up with a computing model that can use the conglomerations of computing resources around the world that are being contributed by different institutions, universities and national labs.”

    It’s no small task. The consortium includes dozens of institutions, and the challenge is ensuring the computers and servers at each are orchestrated together so that everyone on the project can carry out their analyses of the data. A basic challenge, for example, is making sure a computer in Switzerland or Brazil recognizes a login from a computer at Fermilab.

    Coordinating computing resources across a distributed grid has been done before, most notably by the Worldwide LHC Computing Grid, which federates the United States’ Open Science Grid and others around the world. But this is the first time an experiment at this scale led by Fermilab has used this distributed approach.

    “Much of the Worldwide LHC Computing Grid design assumes data originates at CERN and that meetings will default to CERN, but as DUNE now has an associate membership of WLCG things are evolving,” said Andrew McNab, DUNE’s international technical lead for computing. “One of the first steps was hosting the monthly WLCG Grid Deployment Board town hall at Fermilab last September, and DUNE computing people are increasingly participating in WLCG’s task forces and working groups.”

    “We’re trying to build on a lot of the infrastructure and software that’s already been developed in conjunction with those two efforts and extend it a little bit for our specific needs,” Kirby said. “It’s a great challenge to coordinate all of the computing around the world. In some sense, we’re kind of blazing a new trail, but in many ways, we are very much reliant on a lot of the tools that were already developed.”

    Supernovae signals

    Another challenge is that DUNE has to organize the data it collects differently from particle accelerator physics experiments.

    “For us, a typical neutrino event from the accelerator beam is going to generate something on the order of six gigabytes of data,” Kirby said. “But if we get a supernova neutrino alert,” in which a neutrino burst from a supernova arrives, signaling the cosmic explosion before light from it arrives at Earth, “a single supernova burst record could be as much as 100 terabytes of data.”

    One terabyte equals one trillion bytes, an amount of data equal to about 330 hours of Netflix movies. Created in a few seconds, that amount of data is a huge challenge because of the computer processing time needed to handle it. DUNE researchers must begin recording data soon after a neutrino alert is triggered, and it adds up quickly. But it will also offer an opportunity to learn about neutrino interactions that take place inside supernovae while they’re exploding.

    McNab said DUNE’s computing requirements are also slightly different because the size of each of the events it will capture is typically 100 times larger than the LHC experiments like ATLAS or CMS.

    “So, the computers need more memory — not 100 times more, because we can be clever about how we use it, but we’re pushing the envelope certainly,” McNab said. “And that’s before we even start talking about the huge events if we see a supernova.”

    Georgia Karagiorgi, a physicist at Columbia University who leads data selection efforts for the DUNE Data Acquisition Consortium, said a nearby supernova will generate up to thousands of interactions in the DUNE detector.

    “That will allow us to answer questions we have about supernova dynamics and about the properties of neutrinos themselves,” she said.

    To do so, DUNE scientists will have to combine data on the timing of neutrino arrival, their abundance and what kinds of neutrinos are present.

    “If neutrinos have weird, new types of interactions as they’re propagating through the supernova during the explosion, we might expect modifications to the energy distribution of those neutrinos as a function of time” as they are picked up by the detector, Karagiorgi said. “That goes hand-in-hand with very detailed, and also quite computationally intensive, simulations, with different theoretical assumptions going into them, to actually be able to extract our science. We need both the theoretical simulations and the actual data to make progress.”

    Gathering that data is a huge endeavor. When a supernova event occurs, “we read out our far-detector modules for about 100 seconds continuously,” Kirby said.

    Because the scientists don’t know when a supernova will happen, they have to start collecting data as soon as an alert occurs and could be waiting for 30 seconds or longer for the neutrino burst to conclude. All the while, data could be piling up.

    To prevent too much buildup, Kirby said, the experiment will use an approach called a circular buffer, in which memory that doesn’t include neutrino hits is reused, not unlike rewinding and recording over the tape in a video cassette.

    McNab said the supernovae aspect of DUNE is also presenting new opportunities for computing collaboration.

    “I’m a particle physicist by training, and one of my favorite aspects about working on this project is that way that it connects to other scientific disciplines, particularly astronomy,” he said. In the UK, particle physics and astronomy computing are collectively providing support for DUNE, the Vera C. Rubin Observatory Legacy Survey of Space and Time, and the Square Kilometer Array radio telescopes on the same computers. “And then we have the science aspect that, if we do see a supernova, then we will hopefully be viewing it with multiple wavelengths using these different instruments. DUNE provides an excellent pathfinder for the computing, because we already have real data coming from DUNE’s prototype detectors that needs to be processed.”

    Kirby said that the computing effort is leading to exciting new developments in applications on novel architectures, artificial intelligence and machine learning on diverse computer platforms.

    “In the past, we’ve focused on doing all of our data processing and analysis on CPUs and standard Intel and PC processors,” he said. “But with the rise of GPUs [graphics processing units] and other computing hardware accelerators such as FPGAs [field-programmable gate arrays] and ASICs [application-specific integrated circuits], software has been written specifically for those accelerators. That really has changed what’s possible in terms of event identification algorithms.”

    These technologies are already in use for the on-site data acquisition system in reducing the terabytes per second generated by the detectors down to the gigabytes per second transferred offline. The challenge that remains for offline is figuring out how to centrally manage these applications across the entire collaboration and get answers back from distributed centers across the grid.

    “How do we stitch all of that together to make a cohesive computing model that gets us to physics as fast as possible?” Kirby said. “That’s a really incredible challenge.”

    This work is supported by the Department of Energy Office of Science.

    Fermilab is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, please visit energy.gov/science.

    See the full here.


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    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 12:13 pm on April 10, 2020 Permalink | Reply
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    From Fermi National Accelerator Lab: “The cold eyes of DUNE” 

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    From Fermi National Accelerator Lab , an enduring source of strength for the US contribution to scientific research world wide.

    April 9, 2020
    Jerald Pinson

    How do you detect a particle that has almost no mass, feels only two of the four fundamental forces, and can travel unhindered through solid lead for an entire light-year without ever interacting with matter? This is the problem posed by neutrinos, ghostly particles that are generated in the trillions by nuclear reactions in stars, including our sun, and on Earth. Scientists can also produce neutrinos to study in controlled experiments using particle accelerators. One of the ways neutrinos can be detected is with large vats filled with liquid argon and wrapped with a complex web of integrated circuitry that can operate in temperatures colder than the average day on Neptune.

    Industry does not typically use electronics that operate at cryogenic temperatures, so particle physicists have had to engineer their own. A collaboration of several Department of Energy national labs, including Fermilab, has been developing prototypes of the electronics that will ultimately be used in the international Deep Underground Neutrino Experiment, called DUNE, hosted by Fermilab.

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

    SURF DUNE LBNF Caverns at Sanford Lab

    DUNE will generate an intense beam of neutrinos at Fermilab in Illinois and send it 800 miles through the Earth’s crust to detectors in South Dakota. Results from the experiment may help scientists understand why there is more matter than antimatter, an imbalance that led to the formation of our universe.

    2
    Analog-to-digital convertors built to work at cryogenic temperatures, such as the prototype pictured here, will operate inside of liquid-argon chambers in the Deep Underground Neutrino Experiment. Photo: Alber Dyer, Fermilab

    Physics and chill

    DUNE’s neutrino detectors will be massive: a total of four tanks, each as high as a four-story building, will contain a combined 70,000 tons of liquid argon and be situated in a cavern a mile beneath Earth’s surface.

    FNAL DUNE Argon tank at SURF

    Argon occurs naturally as a gas in our atmosphere, and turning it into a liquid entails chilling it to extremely cold temperatures. The atomic nuclei of liquid argon are so densely packed together that some of the famously elusive neutrinos traveling from Fermilab will interact with them, leaving behind tell-tale signs of their passing. The resulting collision produces different particles that scatter in all directions, including electrons, which physicists use to reconstruct the path of the otherwise invisible neutrino.

    A strong electric field maintained within the detector causes the free electrons to drift toward wires attached to sensitive electronics. As the electrons travel past the wires, they generate small voltage pulses that are recorded by electronics in the liquid-argon chamber. Amplifiers in the chamber then boost the signal by increasing the voltage, after which they are converted to digital data. Finally, the signals collected and digitized across the entire chamber are merged together and sent to computers outside the detector for storage and analysis.

    Challenges for chilled electronics

    The electronics in neutrino detectors work the same way as the technology we use in our everyday lives, with one major exception. The integrated circuitry in our phones, computers, cameras, cars, microwaves and other devices has been developed to operate at or around room temperature, down to about minus 40 degrees Celsius. The liquid argon in neutrino detectors, however, is cooled to around minus 200 degrees.

    “If you use electronics designed to work at room temperature, rarely do you find that they work anywhere nearly as well as those designed to operate at cryogenic temperatures,” said Fermilab scientist David Christian.

    In the past, this issue was sidestepped altogether by placing the electronic circuitry outside of the argon tanks. But when you’re measuring a limited number of electrons, even the slightest amount of electronics noise can mask the signal you’re looking for.

    The easiest way to mitigate the problem involves the same tactic you use to keep food from spoiling: Keep it cold. If all the electronics are submerged in the liquid argon, there are fewer thermal vibrations from atoms and a larger signal-to-noise ratio. Placing the electronics in the liquid-argon tank has the added benefit of decreasing the amount of wire you have to use to deliver signals to the amplifiers. If, for example, amplifiers and analog-to-digital converters are kept outside the chamber (as they are in some neutrino detectors), long wires have to connect them to the detectors on the inside.

    “If you put the electronics inside the cold chamber, you have much shorter wires and therefore lower noise,” said Carl Grace, an engineer at Lawrence Berkeley National Laboratory. “You amplify the signal and digitize it in the argon chamber. You then have a digital interface to the outside world in which noise is no longer a concern.”

    There are several design challenges these teams have had to overcome during development, not the least of which was determining how to test the durability of the devices.

    “These chips will have to operate for a minimum of 20-odd years, hopefully longer,” Grace said. “And because of the nature of the argon chambers, the electronics that get put inside of them can’t cannot be changed. They cannot be swapped out or repaired in any way.”

    Since Grace and his team don’t have 20 years in which to test their prototypes, they’ve approximated the effects of aging by increasing the amount of voltage powering the chips to simulate the wear and tear of regular, long-term operation.

    “We take the electronics, cool them down and then elevate their voltage to accelerate their aging,” Grace said. “By observing their behavior over a relatively short period of time, we can we can then estimate how long the electronics would last if they were operated at the voltages for which they were designed.”

    Resistance in circuits

    Not only do these circuits need to be built to last for decades, they also need to be made more durable in another way.

    Electronic circuitry has a certain amount of resistance to the electric current flowing through it. As electrons pass through a circuit, they interact with the vibrating atoms within the conducting material, which slows them down. But these interactions are reduced when the electronics are cooled to cryogenic temperatures, and the electrons that constitute the signal move more quickly on average.

    This is a good thing in terms of output; the integrated circuits being built for DUNE will work more efficiently when placed in the liquid argon. But, as the electrons travel faster through the circuits as temperatures drop, they can begin to do damage to the circuitry itself.

    “If electrons have a high enough kinetic energy, they can actually start ripping atoms from the crystal structure of the conducting material,” Grace said. “It’s like bullets hitting a wall. The wall starts to lose integrity over time.”

    DUNE chips are designed to mitigate this effect. The chips are fabricated using large constituent devices to minimize the amount of damage accrued, and they are used at lower voltages than normally used at room temperature. Scientists can also adjust operating parameters over time to compensate for any damage that occurs during their many years of use.

    Timeline to completion

    With preparations for the DUNE well under way and the experiment slated to begin generating data by 2027, scientists from many institutions have been hard at work developing electronic prototypes.

    Scientists at Brookhaven National Laboratory are working on perfecting the amplifier, while teams from Fermilab, Brookhaven and Berkeley labs are collaborating on the analog-to-digital converter design.

    Fermilab has also teamed up with Southern Methodist University to develop the electronic component that merges all of the data within an argon tank before it’s transmitted to electronics located outside the cold detector. Finally, researchers working on a competing design at SLAC National Accelerator Laboratory are trying to find a way to efficiently combine all three components into one integrated circuit.

    The various teams plan to submit their circuit designs this summer for review. The selected designs will be built and ultimately installed in the DUNE neutrino detectors at the Sanford Underground Neutrino Facility in South Dakota.

    SURF-Sanford Underground Research Facility, Lead, South Dakota, USA

    U.S. work on LBNF/DUNE is supported by the Department of Energy Office of Science.

    See the full here.


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    FNAL Icon

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 12:50 pm on March 28, 2020 Permalink | Reply
    Tags: "March Magnets", 1. Quadrupole magnet for linear particle accelerator, 2. Superconducting focusing magnet for particle collider, 3. Bending magnet for circular accelerator, 4. Undulator for light source, 5. Solenoid for particle detector, 6. Kicker magnet for particle accelerator, 7. Storage ring magnet, 8. Magnetic horn for neutrino beam, FNAL, Illustrations by Jerald Pinson.   

    From Fermi National Accelerator Lab: “March Magnets” 

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    From Fermi National Accelerator Lab , an enduring source of strength for the US contribution to scientific research world wide.

    March 27, 2020
    Maura Barone
    Lauren Biron
    Leah Hesla
    Jerald Pinson
    Kurt Riesselmann

    Missing March Madness? Let Fermilab fill a small part of the void created in these times of social distancing and sheltering-in-place. Participate in our sendup of the NCAA tournament: March Magnets.

    Particle physics fans know that magnets are major players in the instruments scientists use to examine the universe’s smallest constituents. Less appreciated is their sheer variety: diverse purposes, sizes, shapes and materials.

    Below are eight distinct magnet types used in particle physics, each with an example from a project or experiment in which the U.S. Department of Energy’s Fermilab is a player. We start at Elite Eight stage of the playoffs. So add these eight magnets to your repertoire of particle physics knowledge.

    Then on Monday, March 30, head over to the Fermilab Twitter feed to participate in our March Magnets playoffs. On Monday and Tuesday, March 30 and 31, you can vote on which four of our eight magnets get to advance to the next stage. Vote for your Final Four on Friday, April 3. And vote for the champion on Monday, April 6.

    The champion will be announced on Fermilab’s Twitter feed.

    Want to understand how magnets work in the field of particle physics? Read a Physics 101 primer of magnets’ roles in accelerators.

    Have fun with our March Magnets tournament!

    _______________________________________________________________________

    1. Quadrupole magnet for linear particle accelerator

    2
    PIP-II quadrupole magnet. Photo: Reidar Hahn, Fermilab

    What is it?

    Physicists use sequences of quadrupole magnets to keep particle beams focused as they travel through a particle accelerator. At the exact center of these magnets, the magnetic field is zero, and particles feel no force. But the farther a particle deviates from the ideal beam trajectory that goes through the center of these magnets, the stronger the magnetic field. It is these fields that push the charged particles back to the center of the magnet and keep the beam on track.

    Example

    PIP-II linear accelerator quadrupole magnet at Fermilab

    Why it’s cool

    The 26 quadrupole magnets of the new PIP-II linear accelerator at Fermilab, built as in-kind international contributions by the Bhabha Atomic Research Center in India, each have four coils made of copper wire, arranged in alternating orientation (north-south-north-south). The challenge is that a single quadrupole magnet only can create a focusing force in one direction perpendicular to the beam (x axis), and it defocuses the beam in the other direction perpendicular to the beam (y axis). The solution is the installation of a second magnet with switched polarization (south-north-south-north) to create a focusing force along the y-axis direction. The installation of a carefully calculated and placed series of quads with different polarizations, often designed as doublet and triplet magnets, produces a net focusing force and helps ensure that the protons will stay on track.

    Specifications for PIP-II quadrupole magnet

    Size: 0.1 meters long and 0.33 meters high and wide
    Weight: 57 kilograms
    Electric current: 10 amps DC peak
    Strength: 1.5 teslas integrated peak field
    Polarity/magnetic field: quadrupole
    Permanent, superconducting, normal-conducting: normal-conducting electromagnet
    Material: copper, magnetic steel, stainless steel

    3

    _______________________________________________________________________

    2. Superconducting focusing magnet for particle collider

    4
    HL-LHC focusing magnet. Photo: Dan Cheng, Lawrence Berkeley National Laboratory

    What is it?

    A focusing magnet squeezes a charged-particle beam, making it as tight and compact as experiments require. In particle colliders, the stronger the magnets that focus the opposing beams before they reach the collision point, the more collisions the machine produces.

    Example

    Focusing magnet for the High-Luminosity LHC at CERN

    Why it’s cool

    At present, the Large Hadron Collider at CERN has superconducting focusing magnets built with niobium-titanium wire. Now Berkeley Lab, Brookhaven Lab, CERN and Fermilab are working on replacing these magnets as part of the HL-LHC upgrade. The new magnets feature niobium-tin wire, and the first production magnet achieved the required field strength of 11.5 teslas in a test at Brookhaven Lab, a triumph of painstaking and innovative engineering by the U.S. team. It is the result of years of R&D development and understanding how to take advantage of this superior but fragile superconducting material. When installed in the HL-LHC in a few years, it will be the first time a focusing magnet made from niobium-tin will operate in a particle accelerator anywhere in the world.

    Specifications for High-Luminosity LHC focusing magnet (Q1 and Q3)

    Size: 4.7 meters long, 60 centimeters in diameter
    Weight: 6.8 metric tons
    Electric current: 16,500 amps for 7-TeV beams
    Magnetic field strength: 11.5 teslas
    Polarity/magnetic field: quadrupole
    Permanent, normal-conducting or superconducting: superconducting electromagnet
    Material: niobium-tin, iron, aluminum

    5

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    3. Bending magnet for circular accelerator

    5
    Main Injector bending magnet. Photo: Reidar Hahn, Fermilab

    What is it?

    A bending magnet bends the path of a charged-particle beam. Scientists use them to keep a beam on its track in a ring-shaped accelerator. As the machine propels the beam to higher energy, operators keep the particles on their orbit by increasing the electric current in the steering magnets, which increases the strength of the magnet field.

    Example

    Main Injector bending magnet at Fermilab

    Why it’s cool

    The Main Injector bending magnet is, in a word, elegant. And the lab built lots of them, with help from collaborators. Three hundred forty-four bending magnets bend the beam around the Main Injector’s three-kilometer ring. The magnet’s design addresses nearly all of the engineering problems that bedeviled its progenitors. For example, rather than being immovably fixed inside its steel housing, the main magnet component is attached to a sliding mechanism so that, when it expands, it is also free to move, avoiding the stress a fixed component would experience. The copper-wire magnets have performed flawlessly for more than 25 years. Another magnet under development may soon rival it for best magnet: A new Fermilab-designed bending magnet based on superconducting niobium-tin wire is in the development phase for a future very-high-energy particle collider. A demonstrator magnet built by Fermilab set a world record when it achieved a peak magnetic field of 14.1 teslas in 2019.

    Main Injector bending magnet

    Size: two sizes: 4 meters and 6 meters long; roughly 1 meter high and wide
    Weight: about 20 tons
    Electric current: 9,400 amps DC peak
    Strength: 1.7 teslas peak field
    Polarity/magnetic field: dipole
    Permanent, normal-conducting or superconducting: normal-conducting electromagnet
    Material: copper, steel

    6

    _______________________________________________________________________

    4. Undulator for light source

    7
    LCLS-II undulator. Photo: Lawrence Berkeley National Laboratory

    What is it?

    Want to make a particle beam shimmy? Use an undulator, a series of magnets in an electron accelerator. Because the direction of the magnetic field changes from magnet to magnet, the undulator forces a beam into a fast-moving zigzag, rapidly moving left and right. With each zig and zag, the electron beam radiates particles of light, or photons. Scientists use this light to study microscopic details of nature, such as the molecular structure of proteins, how medicine affects cells or the components of air pollution. The spectrum of the light depends on the energy of the particle beam and typically ranges from infrared to ultraviolet and X-rays.

    Example

    Undulator for the LCLS-II electron accelerator at SLAC

    Why it’s cool

    Unlike most light sources, the LCLS-II under construction at SLAC National Accelerator Laboratory features a linear electron accelerator. It propels more electrons to higher energy than typical light sources. Lawrence Berkeley National Laboratory manages the production of the LCLS-II undulators. LCLS-II’s 37 accelerator cryomodules, which power the electron beam before it enters the undulator line, were built by Fermilab and Jefferson Lab.

    The light produced by the undulators of the LCLS-II takes the form of X-rays. Twenty-one undulators produce soft (lower-energy) X-rays; 32 produce hard (higher-energy) X-rays.

    LCLS-II’s soft X-ray undulators are arranged in two rows, which can be adjusted to within millionths of an inch to tune the properties of the X-ray light. They produce up to 1 million soft X-ray pulses per second. The undulators will provide the worldwide brightest X-ray pulses in a wide energy range, from 200 to 25,000 electronvolts, and the photon power will range between several hundred and 1,000 watts.

    Specifications for LCLS-II accelerator undulator

    Size: 3.4 meters long, 2 meters high
    Weight: about 6.5 tons
    Strength: 1.5-tesla peak field
    Polarity/magnetic field: alternating dipole polarity
    Permanent, normal-conducting or superconducting: hybrid permanent magnets
    Material: vanadium permendur energized by a permanent magnet

    8

    _______________________________________________________________________

    5. Solenoid for particle detector

    9
    CMS magnet. Photo: CERN

    What is it?

    A solenoid is a cylindrical electromagnet made of many loops of current-carrying cable, which produces a constant magnetic field along its length. Inside a particle detector, a solenoid is responsible for bending the trajectories of particles that fly through it: Positively charged particles bend one way, and negatively charged particles bend the other. A detector’s solenoid also reveals the particle’s momentum: the faster a particle, the less bending of its path. By analyzing the trajectories, scientists can determine the energy and momentum of each particle.

    Example

    CMS at CERN

    Why it’s cool

    Despite its size, the CMS detector at the Large Hadron Collider is relatively compact for all the material and devices it contains, much smaller than its cousin, the ATLAS detector. Still, its solenoid is a giant — the largest superconducting magnet ever made. Multiple institutions and companies contributed to its construction. It contains almost twice as much iron as the Eiffel Tower, and it stores enough energy to melt 18 tons of gold. The winding of the solenoid cable took five years. Its size and design are optimized for detecting and measuring particles known as muons very accurately.

    Specifications for Compact Muon Solenoid (CMS)

    Size: 13 meters long by 6 meters high
    Weight: about 12,000 tons
    Electric current: 19,500 amps (nominal current)
    Strength: 3.8 teslas
    Polarity/magnetic field: axial field
    Permanent, normal-conducting or superconducting: superconducting electromagnet
    Material: iron, aluminum, niobium-titanium

    10

    _______________________________________________________________________

    6. Kicker magnet for particle accelerator

    11
    Booster kicker magnet. Photo: Salah Chaurize, Fermilab

    What is it?

    Kicker magnets are used in particle accelerators to deflect or transfer a particle beam from its main path, sending particles out of the accelerator and into a beamline that guides the beam to its final destination.

    Example

    Booster kicker magnet at Fermilab

    Why it’s cool

    In the circular Booster accelerator at Fermilab, there are five extraction kicker magnets positioned around the ring. As the beam’s energy ramps up, the particles approach the speed of light as they circle through the Booster. Once the beam reaches its extraction energy, an electrical pulse is transmitted to the five magnets in unison, kicking the beam out of the Booster ring. Because the particle beam passes through the Booster and its kicker magnets up to an astounding 20,000 times a second, the magnets have to activate at unimaginably fast speeds — within 35 nanoseconds — to kick the beam out at exactly the right moment.

    Specifications for Booster kicker magnet

    Size: 1 or 0.5 meters long (two types), 12 centimeters wide
    Weight: 64 kilograms for 1-meter-long magnet
    Electric current: 1,200 amps DC peak
    Strength: 0.0072 teslas
    Polarity/magnetic field: dipole
    Permanent, superconducting or normal-conducting: normal-conducting electromagnet
    Material: copper, aluminum, ferrite ceramic, RTV (silicone rubber)

    12

    _______________________________________________________________________

    7. Storage ring magnet

    13
    Muon g-2 storage ring and magnet. Photo: Reidar Hahn, Fermilab

    What is it?

    Lots of interesting physics experiments need to build up and store bunches of particles. Storage rings are designed to circulate particles from a few seconds to hundreds of hours. Electron storage rings, for example, allow scientists to study the synchrotron radiation the particles emit. Alternatively, scientists can extract the stored particles from the ring and smash them into a fixed target. A collider typically features two intersecting storage rings on top of each other to create head-on collisions of particles.

    Example

    Muon g-2 storage ring magnet at Fermilab

    Why is it cool?

    Most storage rings circulate electrons or protons using a series of magnets. In contrast, the Muon g-2 storage ring at Fermilab circulates muons using one giant magnet: 50 feet in diameter. Built in the 1990s at Brookhaven Lab for its Muon g-2 experiment, the magnet made its journey by boat and truck from New York to Illinois in 2013. The Muon g-2 magnetic field is incredibly uniform for such a large magnet, with a magnetic field that’s identical around the ring at the parts-per-billion level. It has to be so precise because scientists are measuring the “wobble” of the muons traveling through the ring — so if the field varied too much, the muon would behave differently in those areas. The expected announcement of the first results from the Muon g-2 experiment at Fermilab are among the most anticipated physics results of 2020 and, if they confirm the tantalizing hints observed at Brookhaven Lab, could upend the current Standard Model of particle physics.

    Specifications for Muon g-2 magnet

    Size: 15.3 meters in diameter, 1.5 meters tall
    Weight: 700 tons
    Electrical current: 5,200 amps
    Strength: 1.45 tesla
    Polarity/magnetic field: C-shaped dipole magnets and electrostatic quadrupole plates
    Permanent, superconducting or normal-conducting: superconducting electromagnet
    Material: iron and superconducting wire (pure aluminum stabilizer and niobium-titanium superconductor in a copper matrix)

    14
    _______________________________________________________________________

    8. Magnetic horn for neutrino beam

    15
    Neutrino horn. Photo: Reidar Hahn, Fermilab

    What is it?

    Powered by extreme pulses of electricity, magnetic horns turn a broad spray of particles into a focused beam, making for better experiments. Horns typically focus electrically charged particles called pions and kaons, which then decay into various types of particles, including no-charge neutrinos that can no longer be steered by magnets. Because the charged particles are steered by the magnets, the neutrinos they give birth to also continue along well-defined paths. Also called “focusing horns,” these devices live in harsh conditions and make accelerator-based neutrino experiments possible.

    Example

    NuMI focusing horn at Fermilab

    Why is it cool?

    The focusing horn for the Neutrinos at the Main Injector facility receives its beam from Fermilab’s most powerful particle accelerator, the two-mile-circumference Main Injector. The magnetic horn turns on and off rapidly, with every pulse clocking in around 200,000 amps. (Your toaster runs at around 10 amps). Horns must survive extreme thermal and magnetic stress over their lifetimes – the equivalent of being hit with a hammer 10 million times a year. Without the horn, an experiment would lose 95% of the neutrinos in its beam.

    Specifications for NuMI focusing horn:

    Size: 3 meters long
    Weight: about 1 ton
    Electrical current: 200,000 amps
    Strength: 1 tesla
    Polarity/magnetic field: toroidal magnetic field
    Permanent, superconducting or normal-conducting: normal-conducting electromagnet
    Material: nickel-plated aluminum and anodized aluminum

    16

    _______________________________________________________________________

    Illustrations by Jerald Pinson.

    Accelerator magnet research and development at Fermilab is supported by the DOE Office of Science.

    Fermilab is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, visit http://www.science.energy.gov.

    See the full here.


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    FNAL Icon

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
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