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  • richardmitnick 11:02 am on September 22, 2014 Permalink | Reply
    Tags: , Electron Beam Technology, Fermilab,   

    From FNAL- “Feature Breakthrough: nanotube cathode creates more electron beam than large laser system 


    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    Monday, Sept. 22, 2014
    Troy Rummler

    Lasers are cool, except when they’re clunky, expensive and delicate.

    So a collaboration led by RadiaBeam Technologies, a California-based technology firm actively involved in accelerator R&D, is designing an electron beam source that doesn’t need a laser. The team led by Luigi Faillace, a scientist at RadiaBeam, is testing a carbon nanotube cathode — about the size of a nickel — in Fermilab’s High-Brightness Electron Source Lab (HBESL) that completely eliminates the need for a room-sized laser system currently used to generate the electron beam.

    Fermilab was sought out to test the experimental cathode because of its capability and expertise for handling intense electron beams, one of relatively few labs that can support this project.

    Tests have shown that the vastly smaller cathode does a better job than the laser. Philippe Piot, a staff scientist in the Fermilab Accelerator Division and a joint appointee at Northern Illinois University, says tests have produced beam currents a thousand to a million times greater than the one generated with a laser. This remarkable result means that electron beam equipment used in industry may become not only less expensive and more compact, but also more efficient. A laser like the one in HBESL runs close to half a million dollars, Piot said, about hundred times more than RadiaBeam’s cathode.

    The technology has extensive applications in medical equipment and national security, as an electron beam is a critical component in generating X-rays. And while carbon nanotube cathodes have been studied extensively in academia, Fermilab is the first facility to test the technology within a full-scale setting.

    “People have talked about it for years,” said Piot, “but what was missing was a partnership between people that have the know-how at a lab, a university and a company.”

    Piot and Fermilab scientist Charles Thangaraj are partnering with RadiaBeam Technologies staff Luigi Faillace and Josiah Hartzell and Northern Illinois University student Harsha Panuganti and researcher Daniel Mihalcea. A U.S. Department of Energy Small Business Innovation Research grant, a federal endowment designed to bridge the R&D gap between basic research and commercial products, funds the project. The work represents the kind of research that will be enabled in the future at the Illinois Accelerator Research Center — a facility that brings together Fermilab expertise and industry.

    hp
    Harsha Panunganti of Northern Illinois University works on the laser system (turned off here) normally used to create electron beams from a photocathode. Photo: Reidar Hahn

    The new cathode appears at first glance like a smooth black button, but at the nanoscale it resembles, in Piot’s words, “millions of lightning rods.”

    tubre
    The dark carbon-nanotube-coated area of this field emission cathode is made of millions of nanotubes that function like little lightning rods. At Fermilab’s High-Brightness Electron Source Lab, scientists have tested this cathode in the front end of an accelerator, where a strong electric field siphons electrons off the nanotubes to create an intense electron beam. Photo: Reidar Hahn

    “When you apply an electric field, the field lines organize themselves around the rods’ extremities and enhance the field,” Piot said. The electric field at the peaks is so intense that it pulls streams of electrons off the cathode, creating the beam.

    Traditionally, lasers strike cathodes in order to eject electrons through photoemission. Those electrons form a beam by piggybacking onto a radio-frequency wave, synchronized to the laser pulses and formed in a resonance cavity. Powerful magnets focus the beam. The tested nanotube cathode requires no laser as it needs only the electric field already generated by the accelerator to siphon the electrons off, a process dubbed field emission.

    The intense electric field, though, has been a tremendous liability. Piot said critics thought the cathode “was just going to explode and ruin the electron source, and we would be crying because it would be dead.”

    One of the first discoveries Piot’s team made when they began testing in May was that the cathode did not, in fact, explode and ruin everything. The exceptional strength of carbon nanotubes makes the project feasible.

    Still, Piot continues to study ways to optimize the design of the cathode to prevent any smaller, adverse effects that may take place within the beam assembly. Future research also may focus on redesigning an accelerator that natively incorporates the carbon nanotube cathode to avoid any compatibility issues.

    See the full article here.

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  • richardmitnick 12:34 pm on September 19, 2014 Permalink | Reply
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    From Fermilab- “Frontier Science Result: CMS Three ways to be invisible” 


    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    Friday, Sept. 19, 2014
    Jim Pivarski

    There is a common misconception that the LHC was built only to search for the Higgs boson. It is intended to answer many different questions about subatomic particles and the nature of our universe, so the collision data are reused by thousands of scientists, each studying their own favorite questions. Usually, a single analysis only answers one question, but recently, one CMS analysis addressed three different new physics: dark matter, extra dimensions and unparticles.

    CERN CMS New
    CMS

    CERN LHC Grand Tunnel
    CERN LHC Map
    CERN LHC particles
    LHC

    The study focused on proton collisions that resulted in a single jet of particles and nothing else. This can only happen if some of the collision products are invisible — for instance, one proton may emit a jet before collision and the collision itself produces only invisible particles. The jet is needed to be sure that a collision took place, but the real interest is in the invisible part.

    proton
    The quark structure of the proton. The color assignment of individual quarks is arbitrary, but all three colors must be present. Forces between quarks are mediated by gluons

    Sometimes, the reason that nothing else was seen in the detector is mundane. Particles may be lost because their trajectories missed the active area of the detector or a component of the detector was malfunctioning during the event. More often, the reason is due to known physics: 20 percent of Z bosons decay into invisible neutrinos. If there were an excess of invisible events, more than predicted by the Standard Model, these extra events would be evidence of new phenomena.

    The classic scenario involving invisible particles is dark matter. Dark matter has been observed through its gravitational effects on galaxies and the expansion of the universe, but it has never been detected in the laboratory. Speculations about the nature of dark matter abound, but it will remain mysterious until its properties can be studied experimentally.

    Another way to get invisible particles is through extra dimensions. If our universe has more than three spatial dimensions (with only femtometers of “breathing room” in the other dimensions), then the LHC could produce gravitons that spin around the extra dimensions. Gravitons interact very weakly with ordinary matter, so they would appear to be invisible.

    A third possibility is that there is a new form of matter that isn’t made of indivisible particles. These so-called unparticles can be produced in batches of 1½ , 2¾ , or any other amount. Unparticles, if they exist, would also interact weakly with matter.

    All three scenarios produce something invisible, so if the CMS data had revealed an excess of invisible events, any one of the scenarios could have been responsible. Follow-up studies would have been needed to determine which one it was. As it turned out, however, there was no excess of invisible events, so the measurement constrains all three models at once. Three down in one blow!

    LHC scientists are eager to see what the higher collision energy of Run 2 will deliver.

    See the full article here.

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  • richardmitnick 1:45 pm on September 12, 2014 Permalink | Reply
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    From FNAL- “Frontier Science Result: DES Dark Energy Survey discovers new trans-Neptunian objects” 


    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    Friday, Sept. 12, 2014
    David Gerdes, University of Michigan

    three
    Planet hunters, from left: Zhilu Zhang (Carleton College), David Gerdes (University of Michigan) and Ross Jennings (Carleton College)

    Ever wish you could spend your summer vacation exploring someplace cool? Undergraduate students Ross Jennings and Zhilu Zhang, both of Carleton College, got to explore one of the coolest places in the solar system when they accepted research fellowships at the University of Michigan to work with Professor David Gerdes on a search for trans-Neptunian minor planets with the Dark Energy Survey. This faraway region of the solar system, more than five billion kilometers from the sun, is populated by thousands of small, icy worlds that take centuries to complete one orbit. These trans-Neptunian objects (TNOs) are believed to be leftovers from the primordial cloud that gave birth to the solar system.

    two
    These side-by-side images show the new minor planet 2013 QO95. The circled object in the left picture is roughly 200 kilometers in size and lies just beyond Pluto. The bright star in the image is too faint to be seen with the unaided eye. Images: Dark Energy Survey

    Dark Energy Camera
    Dark Energy Camera on the Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory high in the Chilean Andes.

    CTIO Victor M Blanco 4m Telescope
    CTIO Victor M Blanco 4m Telescope interior
    CTIO Victor M Blanco 4m Telescope

    To look for TNOs in Dark Energy Survey data, Gerdes and his students examined the 10 fields that DES visits roughly every five days to search for type Ia supernovae. This search uses difference imaging software to detect transient objects such as a supernova that brightens rapidly and then fades over the next few months. But it’s also the perfect tool to find TNOs, which move from night to night against the background of fixed stars, yet slowly enough that they can stay in the same field of observation for weeks.

    Gerdes, Jennings and Zhang started with a list of nearly 100,000 observations of individual transients, then linked different combinations with trial orbits to see which ones were consistent with a TNO. As more and more points were added to each candidate orbit, the team refined their calculations and made improved predictions for additional observations. By the end of the summer, the team had discovered five new TNOs.

    The properties of the new objects reflect the rich dynamical structure of the trans-Neptunian region: One orbits the sun once for every two orbits of Neptune, and another makes two orbits for every five of Neptune. These orbital resonances protect the objects from disruptive close encounters with the giant planet. A third object has a highly elongated, 1,200-year orbit that is among the 50 longest orbital periods known. (Read more about the fourth and fifth objects.)

    In the course of this summer project, the students learned a variety of skills, from Python programming to the mechanics of submitting results for publication.

    But the most important thing, said Zhang, was this: “You need to really have a lot of enthusiasm for the research you are involved in, because there is a lot of repetition and tedious work involved in research, and it is not about discovering new things every day. However, the joy you get after you finally find something is so special that I haven’t felt anything like that before in my entire life.”

    Now that’s cool.

    See the full article here.

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  • richardmitnick 9:49 am on September 11, 2014 Permalink | Reply
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    From Dr. Don Lincoln at FNAL: “Physics in a Nutshell Epic facepalm” 


    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    FNAL Don Lincoln
    Don Lincoln

    face

    If you’re a science enthusiast, this week you have likely encountered outlandish headlines invoking Stephen Hawking, the Higgs boson and the end of the universe. I hope you had the presence of mind to react as the famous actor in the picture did. Let’s start with the answer first. The universe is safe and will be for a very long time — for trillions of years. This story as widely reported by the media is a jaw-dropping misrepresentation of science.

    To understand how abominably Hawking’s statement was twisted, first we need to understand the statement. To paraphrase just a little, Hawking said that in a world in which the Higgs boson and the top quark have the masses that scientists have measured, the universe is in a metastable state.

    So let’s take those pieces one at a time. What does “metastable” mean? Basically, metastable means “kind of stable.” So what does that mean? Let’s consider an example. Take a pool cue and lay it on the pool table. The cue is stable; it’s not going anywhere. Take the same cue and balance it on your finger. That’s unstable; under almost any circumstances, the cue will fall over. So the terms stable and unstable are easy and have familiar, real-world analogues. The analogy for a metastable object is a barstool. Under almost all circumstances, the stool will sit there for all eternity. However, if you bump the stool hard enough, it will fall over. When the stool has fallen over, it is now more stable than it was, just like the pool cue lying on the table.

    Now we need to bring in the universe and the laws that govern it. Here is an important guiding principle: The universe is lazy — a giant, cosmic couch potato. If at all possible, the universe will figure out a way to move to the lowest energy state it can. A simple analogy is a ball placed on the side of a mountain. It will roll down the mountainside and come to rest at the bottom of the valley. This ball would then be in a stable configuration. The universe is the same way. After the cosmos was created, the fields that make up the universe should arrange themselves into the lowest possible energy state.

    pool
    A stable thing is something that won’t change, like this pool cue on the table. An unstable thing is something that will quickly change, like this pool cue balanced on the man’s hand. A metastable thing will eventually change, but will not do so quickly or easily. An example is this stool, which is more stable when it is lying down, but it will stay upright for long periods of time.

    There is a proviso. Just as on a slope of a mountain, where there may be a little valley part way up the hill (above the real valley), it is possible that there could be little “valleys” in the energy slope. As the universe cooled, it could be that it might have been caught in one of those little valleys. Ideally, the universe would like to fall into the deeper valley below, but it could be trapped. This is an example of a metastable state. As long as the little valley is deep enough, it’s hard to get out of. Indeed, using classical physics, it is impossible to get out of it.

    However, we don’t live in a classical world. In our universe, we must take into account the nature of quantum mechanics. There are many ways to describe the quantum realm, but one of the properties most relevant here is “rare things happen.” In essence, if the universe was trapped in a little valley of metastability, it could eventually tunnel out of the valley and fall down into the deeper valley below.

    So what are the consequences of the universe slipping from one valley to another? Well, the rules of the universe are governed by the valley in which it finds itself. In the metastable valley that defines our familiar universe, we have the rules of physics and chemistry that allow matter to assemble into atoms and, eventually, us. If the universe slipped into a different valley, the rules that govern matter and energy would be different. This means, among other things, quarks and leptons might be impossible. The known forces might not apply. In short, there is no reason to think we’d exist at all.

    graph
    Whether our universe is in a stable configuration, an unstable configuration or a metastable one depends on the mass of the Higgs boson and the mass of the top quark. The dot shows tells us the value of those parameters in our universe. We see that it appears that the universe appears to be metastable but, as noted in the text, there is clearly a lot still to be understood before we can be sure.

    This leads us to ask how the transition would occur. Would we have any warning? Actually, we’d have no warning at all. If, somewhere in the cosmos, the universe made a transition from a metastable valley to a deeper one, the laws of physics would change and sweep away at the speed of light. As the shockwave passed over the solar system, we’d simply disappear as the laws that govern the matter that makes us up would just cease to apply. One second we’d be here; the next we’d be gone.

    Coming back to the original question, what does the Higgs boson tell us about this? It turns out that we can use the Standard Model to tell us whether we are in a stable, unstable or metastable universe. We know we don’t live in an unstable one, because we’re here, but the other two options are open. So, what is the answer? It depends on two parameters: the mass of the top quark and the mass of the Higgs boson. As we see in the figure [below], our universe appears to be in a metastable state, although it is quite close to the stable region. The size of the box reflects our uncertainty in our measurements.

    sm
    The Standard Model of elementary particles, with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    measure
    In the context of the cosmos, the universe prefers to be in the lowest energy state. However it is possible that our familiar cosmos is in a little valley higher up the slope. In this little valley, the rules of matter with which we are familiar reign supreme. However, if the universe ever transitions to the lower valley, the rules of physics might change entirely. Those new rules could be anything, including ones in which matter doesn’t exist. It probably doesn’t need saying, but for my Chicago readers, I should caution them that a universe in which the Cubs win the World Series is still exceedingly unlikely.

    So if we follow our understanding of the Standard Model, combined with our best measurements, it appears that we live in a metastable universe that could one day disappear without warning. You can be forgiven if you take that pronouncement as a reason to indulge in some sort of rare treat tonight. But before you splurge too much, take heed of a few words of caution. Using the same Standard Model we used to figure out whether the cosmos is metastable, we can predict how long it is likely to take for quantum mechanics to let the universe slip from the metastable valley to the stable one, and it will take trillions of years. Mankind has only existed for about 100,000 years, and the sun will grow to a red giant and incinerate the Earth in about five billion years. Since we’re talking about the universe existing as a metastable state for trillions of years, maybe overindulging tonight might be a bad idea.

    It is important to note that finding the Higgs boson has no effect on whether the universe is in a metastable state. If we live in a metastable cosmos, it has been that way since the universe was created. It’s like living in a century-old house that was built with a ticking time bomb hidden in its walls. Finding the Higgs boson is like hearing the ticking of the bomb that was always there. I must repeat: The discovery of the Higgs boson has no effect at all on whether the universe is in a metastable state.

    Returning to the original, overly hyped media stories, you can see that there was a kernel of truth and a barrel full of hysteria. There is no danger, and it’s completely OK to resume watching with great interest the news reports of the discovery and careful measurement of the Higgs boson. And, yes, you have to go to work tomorrow.

    See the full article here.

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  • richardmitnick 2:09 pm on September 5, 2014 Permalink | Reply
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    From FNAL: “Feature – Neutrinos permeate Fermilab’s past, present and future” 


    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    Friday, Sept. 5, 2014
    Troy Rummler

    It was called Target Station C. One of three stations north of Wilson Hall at the end of beamlines extending from the Main Ring (later replaced by the Tevatron), Target Station C was assigned to experiments that would require high beam intensities for investigating neutrino interactions, according to a 1968 design report.

    Fermilab Tevatron
    Tevatron at FNAL

    Within a few years, Target Station C was officially renamed the Neutrino Area. It was the first named fixed-target area and the first to be fully operational. Neutrinos and the Intensity Frontier had an early relationship with Fermilab. But why is it resurfacing now?

    “The experimental program is driven by the current state of knowledge, and that’s always changing,” said Jeffrey Appel, a retired Fermilab physicist and assistant laboratory director who started research at the lab in 1972.

    When Appel first arrived, there was intense interest in neutrinos because the weak force was poorly understood, and neutral currents were still a controversial idea. Fermilab joined forces with many institutions both in and outside the United States, and throughout the 1970s and early 1980s, neutrinos generated from protons in the Main Ring crashed through a 15-foot bubble chamber filled with super-heated liquid hydrogen. Other experiments running in parallel recorded neutrino interactions in iron and scintillator.

    “The goal was to look for the W and Z produced in neutrino interactions,” said Appel. “So the priority for getting the beam up first and the priority for getting the detectors built and installed was on that program in those days.”

    It turns out that the W and Z bosons are too massive to have been produced this way and had to wait to be discovered at colliding-beam experiments. As soon as the Tevatron was ready for colliding beams in 1985, the transition began at Fermilab from fixed-target areas to high-energy particle colliding.

    More recent revelations have shown that neutrinos have mass. These findings have raised new questions that need answers. In 1988, plans were laid to add the Main Injector to the Fermilab campus, partly to boost the capabilities of the Tevatron, but also, according to one report, because “intense beams of neutral kaons and neutrinos would provide a unique facility for CP violation and neutrino oscillation experiments.”

    Although neutrino research was a smaller fraction of the lab’s program during Tevatron operations, it was far from dormant. Two great accomplishments in neutrino research occurred in this time period: One was the most precise neutrino measurement of the strength of the weak interaction by the NuTeV experiment. The other was when the DONUT experiment achieved its goal of making the first direct observation of the tau neutrino in 2000.

    “In the ’90s most evidence of neutrinos changing flavors was coming from natural sources. But this inspired a whole new generation of accelerator-based neutrino experiments,” said Deborah Harris, co-spokesperson for the MINERvA neutrino experiment. “That’s when Fermilab changed gears to make lower-energy but very intense neutrino beams that were uniquely suited for oscillation physics.”

    In partnership with institutions around the globe, Fermilab began planning and building a suite of neutrino experiments. MiniBooNE and MINOS started running in the early 2000s and MINERvA started in 2010. MicroBooNE and NOvA are starting their runs this year.

    Now the lab is working with other institutions to establish a Long-Baseline Neutrino Facility at the laboratory and advance its short-baseline neutrino research program. As Fermilab strengthens its international partnerships in all its neutrino experiments, it is also working to position itself as the home of the world’s forefront neutrino research.

    “The combination of the completion of the Tevatron program and the new questions about neutrinos means that it’s an opportune time to redefine the focus of Fermilab,” Appel explained.

    “Everybody says: ‘It’s not like the old days,’ and it’s always true,” Appel said. “Experiments are bigger and more expensive, but people are just as excited about what they’re doing.”

    He added, “It’s different now but just as exciting, if not more so.”

    See the full article here.

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  • richardmitnick 10:41 am on September 4, 2014 Permalink | Reply
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    From FNAL- “Frontier Science Result: CDF The final word on Z’s and jets from CDF” 


    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    Thursday, Sept. 4, 2014
    edited by Andy Beretvas

    charts
    Inclusive jet pT differential cross sections for Z + one or more jet events. The measured differential cross section (black dots) is compared to the LOOPSIM + MCFM prediction (open circle). On the right many other theoretical predictions are shown.

    Our understanding of the strong force, called QCD (quantum chromodynamics) is very advanced. This theory describes the interactions between some of nature’s fundamental building blocks, quarks and gluons.

    quark
    A proton, composed of two up quarks and one down quark. (The color assignment of individual quarks is not important, only that all three colors be present.)

    inter
    In Feynman diagrams, emitted gluons are represented as helices. This diagram depicts the annihilation of an electron and positron.

    The highly energetic quarks and gluons released in the Tevatron proton-antiproton collisions produce collimated jets of particles, which can be detected by the experiments. These jets were produced in association with particles known as Z bosons.

    Fermilab Tevatron
    Tevatron at Fermilab

    You may know the Z as one of the carriers of the electroweak force, but here our focus is on their production in association with jets. The behavior of both the Z and the jets is predicted by the strong force.

    Scientists at the Tevatron experiments have made many measurements of the Z particle, which decays into a pair of leptons (electrons or muons) and jets. Our results correspond to the full Tevatron Run II data set (9.6 inverse femtobarns). In this experiment we are concerned with comparing measured probabilities with theoretical predictions. This is complicated because we must understand how well the detector records the decay particles’ tracks and energies for the process of Z boson and jet production.

    The inclusive Z-plus-jets decay probabilities are measured for one, two, three and four jets. The results shown are from combining the decay modes in which the Z decays into an electron pair and in which it decays into a muon pair. This is the first CDF measurement of probabilities for decays into a Z particle and three or more jets.

    The samples are very clean, and for the cases in which they include one or more jets, they contain only about 1.5 percent background. In the upper figure you can see results for the transverse momentum of the leading jet’s differential reaction probability for Z plus one or more jet events.

    This result is of great interest to many theoretical physicists as can be seen by the large number of predictions. The agreements are good as can be expected, as theorists have looked at earlier results from CDF and DZero. The most accurate predictions are those of a simulation program called LOOPSIM + MCFM. This is an important Tevatron legacy measurement.

    Fermilab CDF
    CDF at Fermilab

    Fermilab DZero
    DZero at Fermilab

    The results show beautiful agreement between theory and experiment and are important for understanding the association of Z and jets in searches for non-Standard Model physics.

    See the full article here.

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  • richardmitnick 11:49 am on September 3, 2014 Permalink | Reply
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    From Fermilab: “From the Technical Division – Leading the way in superconducting magnets and accelerators” 


    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    Wednesday, Sept. 3, 2014

    hm
    Hasan Padamsee, head of the Technical Division, wrote this column.

    I feel very fortunate to head the Technical Division in this era of exciting accelerator technology developments. Our division holds the keys to enabling technologies for frontier accelerators, both in magnet development and accelerator cavities.

    Our niobium titanium magnet program will guide intense muon beams for precision experiments to determine whether muons, which belong to the lepton family, can spontaneously change into other leptons — specifically electrons — just as neutrinos can change into other neutrinos [electron, muon, and tau]. The magnets for the Mu2e experiment will be wound with 45 miles of superconducting cable.

    Our Nb3Sn magnet advances will enable planned upgrades to LHC luminosity guided by the LARP program, led by Giorgio Apollinari. Our Nb3Sn and high-temperature superconductor high-field magnet program, led by Alexander Zlobin, could enable a roughly 100-TeV proton-proton collider, a most powerful tool for future high-energy physics.

    As an expert in superconducting radio-frequency acceleration technology, or SRF, I was thrilled to join Fermilab in June because I saw how the division mastered our new technology to build up the infrastructure and expertise through the International Linear Collider R&D program, which ran under the leadership of Bob Kephart and previous Technical Division Head Dave Harding. To our delight, the SRF Department, led by Slava Yakovlev, had prepared some of the best niobium cavities and assembled them into the world’s highest-gradient ILC cryomodule, with a gradient of 31.5 megavolts per meter. Thus the division played a huge role in getting SRF technology ready for the ILC, if and when it will be built.

    A major consequence of the SRF successes is the decision to upgrade LCLS, the world-class light source at SLAC, using SRF technology. While the ILC must be a pulsed accelerator with a one percent duty factor, meaning that the RF power remains on for only one percent of the time, the LCLS-II light source must run continuously to keep its users happy. Continuous operation is now made economically feasible thanks to spectacular discoveries from the Technical Division.

    Anna Grassellino and Alexander Romanenko discovered new phenomena in SRF that will raise the Q values — measures of how efficiently a cavity stores energy — of ILC-type accelerating cavities from 10 billion to nearly 30 billion. To appreciate the significance of such high Qs, imagine that Galileo’s pendulum oscillator — in the year 1600 — had a Q of 30 billion. It would still be oscillating today and would continue to oscillate to the year 2800! Such high Qs arise thanks to minuscule RF losses, which make it affordable to run superconducting cavities in LCLS-II continuously. The division is gearing up to provide 17 ILC-type cryomodules with 136 cavities, as well as two cryomodules with higher-frequency cavities.

    To reap the benefits at home, SRF is also the foundation of a brand new accelerator, called PIP-II, to be constructed at Fermilab to provide the world’s best neutrino beams. PIP-II will be built in collaboration with other labs to provide a 1-megawatt proton beam accelerated by an 800-MeV superconducting linac. The linac will contain almost 20 cryomodules with more than 110 SRF cavities. The prototype cavities have been constructed and tested successfully, and the first prototype cryomodules will be assembled next year.

    Both superconducting magnets and superconducting RF have brilliant futures at Fermilab. I am proud to lead these exciting developments to keep Fermilab at the frontier of high-energy physics.

    See the full article here.

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  • richardmitnick 12:18 pm on August 30, 2014 Permalink | Reply
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    From Don Lincoln at Fermilab: “Particle Detectors Subatomic Bomb Squad ” a Great Video 


    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    The manner in which particle physicists investigate collisions in particle accelerators is a puzzling process. Using vaguely-defined “detectors,” scientists are able to somehow reconstruct the collisions and convert that information into physics measurements. In this video, Fermilab’s Dr. Don Lincoln sheds light on this mysterious technique. In a surprising analogy, he draws a parallel between experimental particle physics and bomb squad investigators and uses an explosive example to illustrate his points. Be sure to watch this video… it’s totally the bomb.

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  • richardmitnick 11:31 am on August 29, 2014 Permalink | Reply
    Tags: , Fermilab,   

    From Fermilab: “Physics in a Nutshell – Invisibility squared” 


    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    Friday, Aug. 29, 2014
    Jim Pivarski

    What does it mean for something to be invisible? If it does not reflect light with the right wavelengths, it is not visible to humans, though it might be detected by a specialized instrument. Neutral particles, such as the neutrons in an atom, do not interact with photons of any wavelength (unless the wavelength is small enough to resolve individual charged quarks within the neutron). Thus, they are invisible to nearly every instrument that uses electromagnetic radiation to see.

    cat
    The former presence of a cat on the patio can be inferred from where the rain didn’t land. Similarly, sterile neutrinos may be inferred from their effects on normal neutrinos, which themselves are barely visible.

    neut
    The quark structure of the neutron. (The color assignment of individual quarks is not important, only that all three colors are present.)

    However, neutrons are easy to detect in other ways. They interact through the strong and weak nuclear forces, and neutron detectors take advantage of these interactions to “see” them. Neutrinos, on the other hand, are still more invisible, since they have no constituent quarks and interact only through the weak force. Billions of neutrinos pass through every square centimeter per second, but only a handful of these per day are detectable in a room-sized instrument.

    q
    A proton, composed of two up quarks and one down quark. (The color assignment of individual quarks is not important, only that all three colors be present.)

    Now suppose there were another kind of neutrino that did not interact with the weak force. Physicists would call such a particle a sterile neutrino if it existed. How could it be detected? If something can’t be detected, does it even make sense to talk about it? Could there be a whole world of other particles, filling the same space we do, that can never be detected because they don’t interact with anything that interacts with our eyeballs?

    In principle, anything that has mass or energy can be detected because it interacts gravitationally. That is, if there were a sterile neutrino planet right next to the Earth, then it would change the way that satellites orbit: This is our gravitational detector. However, a small mass, such as an individual particle, would deflect orbits so little that it could not be detected in practice.

    Although sterile neutrinos would have no effect on ordinary matter, they could be detected through what they do to other neutrinos. Neutrinos of different types mix quantum mechanically. That is, muon neutrinos created by a muon beam can become electron neutrinos and tau neutrinos when they are detected. If there were a fourth, sterile, type of neutrino, then the visible neutrinos would also partly transition to sterile neutrinos in flight and change the fractions of the three visible types of neutrinos in the detector.

    In the mid-1990s, an experiment called LSND saw what looked like a sterile neutrino signal, so MiniBooNE, an experiment at Fermilab, studied the effect in more detail. As the MiniBooNE scientists investigated, the story got weirder: the numbers of visible neutrinos didn’t add up, but at different energies than expected. No simple explanation makes sense of the data, but it is possible that a sterile neutrino might. A future experiment, MicroBooNE, will study this phenomenon with higher sensitivity. It would be impressive if the key to new physics is an invisible particle, glimpsed only through its effect on nearly invisible particles!

    See the full article here.

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  • richardmitnick 11:12 am on August 29, 2014 Permalink | Reply
    Tags: , Fermilab,   

    From Fermilab: “Frontier Science Result- ArgoNeuT 20 years later: Neutrino-induced coherent pions are back to Fermilab “ 


    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    Friday, Aug. 29, 2014
    Edward Santos, Imperial College London, and Tingjun Yang, Fermilab

    The neutrino is known for how rarely it interacts with matter. But when it does, the interaction can take place numerous ways, and some interaction types happen more often than others. The ArgoNeuT experiment recently looked at one of the more rare cases — one that comes to only about 1 percent of all the possible ways a neutrino can interact. As one might expect, its infrequency poses a great challenge in our efforts to measure it.

    scale
    Display of an event captured in the ArgoNeuT detector. The track on the top corresponds to a muon, the one below it is a charged pion. These particles are produced by the interaction of a muon neutrino with an argon atom in the detector.

    This month, the ArgoNeuT collaboration released a new measurement of this rare interaction, called charged-current coherent pion production induced by neutrinos on nuclei. In this process, a neutrino interacts with a nucleus as a whole, producing a muon and a pion without breaking the nucleus apart or leaving it in an excited state. Seen in the detector, the events look like the one shown above, where two very forward-going tracks leave the interaction point.

    pion
    The quark structure of the pion.

    Historically, there have been only a handful of experiments that observed coherent pion production. Back in 1993, the FNAL E632 experiment, conducted using a 15-foot bubble chamber, measured interactions of this type at a neutrino energy of 70 to 90 GeV. In more recent years, the K2K and SciBooNE experiments also attempted to measure this cross section at a much lower energy (1 to 2 GeV) but found no sign of it in the charged-current channel. The null results motivated renewed interest by the theoretical community, who modified the favored models of the time and proposed new ones.

    These days, Fermilab’s ArgoNeuT and MINERvA collaborations are in hot pursuit of these interactions, measuring them using the low-energy NuMI beam. The ArgoNeuT collaboration has measured the likelihoods of charged-current pion production, reporting the interactions with neutrinos and antineutrinos at the mean energies of 3.6 GeV and 10 GeV, respectively. These measured probabilities, the results of a five-month run of antineutrino-enhanced NuMI beam, are in good agreement with theoretical predictions and are attracting much interest within the neutrino community.

    This is the first time that scientists measured the process in a liquid-argon detector and using an automated reconstruction. Researchers also once again demonstrated the potential of the liquid-argon technique for the measurement of neutrino interactions. Key pieces of this success were ArgoNeuT’s capabilities for precisely measuring the particles ejected from a neutrino interacting with an argon nucleus.

    Although ArgoNeuT’s small detector size limits the precision of this measurement, the techniques developed during this analysis will be used by future, larger experiments, such as MicroBooNE and LAr1-ND, to gain new insights into coherent pion production.

    See the full article here.

    Fermilab Campus

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