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  • richardmitnick 1:32 pm on February 14, 2019 Permalink | Reply
    Tags: , , , , , Dark Matter Research, , , The Kavli Institute for the Physics and Mathematics of the Universe   

    From The Kavli Institute for the Physics and Mathematics of the Universe: “New Map of Dark Matter Puts the Big Bang Theory on Trial” 

    KavliFoundation

    From The Kavli Institute for the Physics and Mathematics of the Universe

    Kavli IPMU
    Kavli IMPU

    The prevailing view of the universe has just passed a rigorous new test, but the mysteries of dark matter and dark energy remain frustratingly unsolved.

    Dark Matter Research

    Universe map Sloan Digital Sky Survey (SDSS) 2dF Galaxy Redshift Survey

    Scientists studying the cosmic microwave background hope to learn about more than just how the universe grew—it could also offer insight into dark matter, dark energy and the mass of the neutrino.

    Dark matter cosmic web and the large-scale structure it forms The Millenium Simulation, V. Springel et al

    Dark Matter Particle Explorer China

    DEAP Dark Matter detector, The DEAP-3600, suspended in the SNOLAB deep in Sudbury’s Creighton Mine

    LUX Dark matter Experiment at SURF, Lead, SD, USA

    ADMX Axion Dark Matter Experiment, U Uashington

    A NEW COSMIC MAP was unveiled in August, plotting where the mysterious substance called dark matter is clumped across the universe.

    Dark Energy Survey


    Dark Energy Camera [DECam], built at FNAL


    NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam at an altitude of 7200 feet

    To immense relief—and frustration—the map is just what scientists had expected. The distribution of dark matter agrees with our current understanding of a universe born with certain properties in a Big Bang, 13.8 billion years ago.

    But for all the map’s confirmatory power, it still tells us little about the true identity of dark matter, which acts as an invisible scaffold for galaxies and cosmic structure. It also does not explain an even bigger factor shaping the cosmos, known as dark energy, an enigmatic force seemingly pushing the universe apart at ever greater speeds. Tantalizingly, however, a small discrepancy between the new findings and previous observations of the early universe might just crack open the door for new physics.

    To discuss these issues, The Kavli Foundation turned to three scientists involved in creating this new cosmic map, compiled by the Dark Energy Survey.

    Adam Hadhazy, Fall 2017

    The participants were:

    SCOTT DODELSON – is a cosmologist and the head of the Department of Physics at Carnegie Mellon University. He is one of the lead scientists behind the Dark Energy Survey’s new map of cosmic structure, which he worked on at the Fermi National Accelerator Laboratory and as a professor at the Kavli Institute for Cosmological Physics at the University of Chicago.

    3
    Map of dark matter made from gravitational lensing measurements of 26 million galaxies in the Dark Energy Survey. The map covers about 1/30th of the entire sky and spans several billion light years in extent. Red regions have more dark matter than average, blue regions less dark matter. Image credit: Chihway Chang/Kavli Institute for Cosmological Physics at the University of Chicago/DES Collaboration.

    RISA WECHSLER – is an associate professor of physics at Stanford University and the SLAC National Accelerator Laboratory, as well as a member of the Kavli Institute for Particle Astrophysics and Cosmology. A founder of the Dark Energy Survey, Wechsler is also involved in two next-generation projects that will delve even deeper into the dark universe.
    GEORGE EFSTATHIOU – is a professor of astrophysics and the former director of the Kavli Institute for Cosmology at the University of Cambridge. Along with his work on the Dark Energy Survey, Efstathiou is a science team leader for the European Space Agency’s Planck spacecraft, which between 2009 and 2013 created a detailed map of the early universe.

    The following is an edited transcript of their roundtable discussion. The participants have been provided the opportunity to amend or edit their remarks.

    THE KAVLI FOUNDATION: The Dark Energy Survey just confirmed that matter as we know it makes up only four percent of the universe. That means 96 percent is stuff we can neither see nor touch, and we have pretty much no idea what it really is. Why are these new findings actually good news?

    RISA WECHSLER: It does seem very strange that the results are good news, right? Forty years ago, nobody would’ve guessed that we apparently live in a universe in which most of the matter is stuff that doesn’t interact with us, and most of the energy is not even matter! It’s still super mind-blowing.

    But we’ve kept making increasingly precise measurements of the universe, and that’s where the Dark Energy Survey results come in. They are the most precise measurements of the density of matter and how it’s clumped in the local universe. In the past, we have measured the density of matter in the young, distant universe. So the Dark Energy Survey is really allowing us to test our understanding of the universe’s evolution, which we’ve formalized as the standard model of Big Bang cosmology, in a totally new way.

    Still, it’s certainly possible that we may have something wrong.

    SCOTT DODELSON: These data, along with precise measurements taken by other projects, might start showing small hints of disagreement, or tension, as we call it, with our current understanding of how the universe began and is now actually expanding at increasing speeds.

    As Risa just said, we’re not sure our current way of thinking is correct because it essentially requires us to make stuff up, namely dark matter and dark energy. It could be that we really are just a month away from a scientific revolution that will upend our whole understanding about cosmology and does not require these things.

    GEORGE EFSTATHIOU: Those measurements of the matter and energy in the young, distant universe that Risa referred to were obtained just a few years ago, when a different program called Planck looked at the relic radiation of the Big Bang, which we call the cosmic microwave background [CMB, see below]. Although the Planck spacecraft’s measurements support the model we’re talking about, one is always uneasy having to postulate things, like dark matter and dark energy, that have not been observed. That’s why the Dark Energy Survey is very important—it can stringently test our knowledge about the birth of the universe by comparing it to the actual structure of the modern-day and young universe.

    TKF: The Dark Energy Survey kicked off four years ago, so you’ve been waiting a long time for these results to come in. What was your initial reaction?

    DODELSON: It was the most amazing experience of my scientific career. On July 7, 2017, a date I will always remember, we had 50 people join a conference call. No one knew what the data were going to say because they were blinded, which guards against accidentally biasing the results to be something you “want” them to be. Then one of the leaders of the lensing analysis, Michael Troxel, ran a computer script on the data, unblinding it, and shared his screen with everybody on the call. We all got to see our results compared to Planck’s. They were in such close agreement, independently of each other. We all just gasped and then clapped.

    WECHSLER: I was on that conference call, too. It was really exciting. I’ve been working on this survey since we wrote the first proposal in 2004, so it felt like a culmination.

    TKF: In 2013, Planck gave us a highly accurate “baby” picture of the universe.

    CMB per ESA/Planck

    ESA/Planck 2009 to 2013

    Now we have a highly precise picture of the universe in a later epoch. George, you were a leader on the Planck mission. What do you see when you look at these two different snapshots in time?

    EFSTATHIOU: The “baby” picture is consistent with a universe mostly made of dark matter and dark energy. It is also consistent with the idea that the universe underwent an exponential expansion in its earliest moments, known as inflation.

    Inflation

    4
    Alan Guth, from Highland Park High School and M.I.T., who first proposed cosmic inflation

    HPHS Owls

    Lambda-Cold Dark Matter, Accelerated Expansion of the Universe, Big Bang-Inflation (timeline of the universe) Date 2010 Credit: Alex MittelmannColdcreation

    Alan Guth’s notes:
    5

    So how does the baby picture extrapolate to the modern, “grown up” universe? As the new Dark Energy Survey results show, the pictures are remarkably consistent.

    DODELSON: We’re all astonished that these two pictures agree to the extent they do. Here’s an example. Let’s say you bought Berkshire Hathaway stock in 1970. Say it was $10 a share then and today it’s $250,000 a share. If you were to predict back then that today it would be $250,000, plus or minus $1,000, people would’ve thought you were nuts. But basically, that’s what we’ve done. When the universe was very young, only 380,000 years old, it was also very “smooth.” Matter was so evenly distributed. Today though—more than 13 billion years later—matter in the cosmos is highly, highly clumped in galaxies, stars, planets and other objects. This is what one would anticipate with cosmic expansion, and with the Dark Energy Survey, we’ve been able to confirm the prediction of this cosmic unevenness to a remarkable degree.

    WECHSLER: What’s really helped us make the precise measurements with Dark Energy Survey is that for the first time, we’re looking over a much larger area, about one-thirtieth, of the sky. That’s three or four times larger than the largest dark matter map we have ever made before. We are also able to make that map essentially over half the age of the universe, from now until about seven billion years ago, by collecting light shining from distant galaxies. So we’re able to tell this story over half of the universe’s history, and it remains consistent throughout.

    There are some small disagreements with the Planck results, but I don’t think we should be too worried yet about them.

    EFSTATHIOU: It would’ve been very interesting if the results had significantly increased the tension with the cosmological standard model, which is the foundation for understanding why, beginning with the Big Bang, the universe is undergoing an accelerated expansion. Some previous surveys had suggested that there might be a problem, though I thought that these results were questionable. In my view, one should rely on the data and not be alarmed if our theories disagree with observations. The universe is what it is.

    TKF: Yet a Nature News story characterized George’s view on the discrepancies as “worrisome.”

    EFSTATHIOU: Well, yes, there have been some claims of tension between the clumping measured in the local universe and Planck’s observations of the distant universe. Some other observations have suggested that the late-time, local universe is expanding at a faster rate than expected from Planck.

    If we were able to say convincingly that there was a real problem posed by any of these individual pieces of data, then we’d have to abandon our standard model of cosmology. We would need new physics, and the sort of physics that we would need would be in the exotic territory, overturning decades of otherwise independently supported physical laws. So it’s a big deal.

    In the past, these sorts of tensions have come and gone. When we wrote the 2013 Planck papers, the results then were in tension with most of astrophysics. Then two years later, some of these tensions had disappeared, and now in 2017, they’ve reemerged. So these things come and go. We need to set a high threshold for our science before launching into explanations based on new physics.

    TKF: It almost sounds like, “if it ain’t broke yet, don’t fix it.”

    EFSTATHIOU: We need to be sure it’s broke before fixing it.

    WECHSLER: I agree with George. There’s a very high bar to show you really understand all of the potential sources of error before taking the big leap of abandoning our current, well-evidenced conception about the universe. I don’t think we’re there yet. It means that we should be really excited about the continuing Dark Energy Survey, as well as all the other upcoming surveys and projects.

    TKF: Indeed, these new results are based on a year’s-worth of measurements out of a total of five years. What might we expect after four more years of data have been crunched?

    WECHSLER: With four times more data, our map of dark matter will be even more precise. I also expect there will be improvements in our analysis methods. There will also be a bunch of other new things that the Dark Energy Survey should discover, including new dwarf galaxies around our Milky Way galaxy that we’ve long thought must be there but couldn’t find. There’s lots more to look forward to!

    DODELSON: The increased precision Risa just talked about will enable us to hit the standard model of cosmology as hard as it’s ever been hit. Disproving the current model will revolutionize the way we think about the universe, so that’s the most exciting thing that I can imagine happening.

    TKF: How are astrophysicists extending the hunt for dark matter and dark energy? Risa, let’s start with you, because you are closely involved in two next-generation “dark universe” projects.

    WECHSLER: With the Dark Energy Spectroscopic Instrument, or DESI [pronounced “DEZ-ee”], we’ll be getting what we call spectra, or detailed observations of the light from about 35 million galaxies and quasars, which are galaxies that appear extra bright because their central black holes are actively devouring matter.

    LBNL/DESI spectroscopic instrument on the Mayall 4-meter telescope at Kitt Peak National Observatory starting in 2018

    NOAO/Mayall 4 m telescope at Kitt Peak, Arizona, USA, Altitude 2,120 m (6,960 ft)

    Kitt Peak National Observatory of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono O’odham Nation, 88 kilometers 55 mi west-southwest of Tucson, Arizona, Altitude 2,096 m (6,877 ft)

    That’s about 10 times more spectra data than we’ve collected from all instruments, so you can imagine that will be really transformative. With DESI, we will be able to independently measure the universe’s expansion rate and how fast its structure of matter and dark matter grow, both of which are influenced by dark energy. Then when you compare those measurements, you get a precise test of the physics governing the universe. DESI will start in 2019 using a telescope in Arizona.

    The other major new instrument I’m working on is the Large Synoptic Survey Telescope, LSST.

    LSST


    LSST Camera, built at SLAC



    LSST telescope, currently under construction on the El Peñón peak at Cerro Pachón Chile, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile, alongside the existing Gemini South and Southern Astrophysical Research Telescopes.

    It will make observations just like the Dark Energy Survey, but at substantially higher precision. In fact, it will cover about four times more area, and the billions of galaxies it sees will be much deeper and farther away. LSST will be a new observatory, being built in Chile right now, and it’s scheduled to begin in about 2022.

    DODELSON: My guess is that both projects will raise new scientific questions. We’ve already seen that with the Dark Energy Survey. Questions shift over time and evolve, so I’m not sure we know what the most exciting thing we’re going to learn from LSST or DESI is.

    EFSTATHIOU: One of my hopes for Planck was that the standard model of cosmology would break and it didn’t. But wouldn’t it be absolutely great for cosmology and for physics if this happened? So we should plug away and see. Maybe we’ll be lucky.

    TKF: If you had to place a bet on what dark matter and dark energy actually are, where would you put your chips?

    DODELSON: We’re living in an era of cognitive dissonance. There is all this cosmological evidence for the existence of dark matter, but over the last 30 years, we’ve run all these experiments and haven’t found it. My bet is that we’re looking at things all wrong. Someone who’s 8 years old today is going to come around and figure out how to make sense of all the data without evoking mysterious new substances.

    EFSTATHIOU: What odds are you giving on that, Scott?

    DODELSON: I’m betting $2,000 of George’s money. [Laughter]

    EFSTATHIOU: I wouldn’t put a bet on any specific candidate for the dark matter. But I bet that dark energy is the cosmological constant, a fudge factor invented by Einstein describing the density of energy in a vacuum.

    WECHSLER: I’m basically with George on this one. I think if Scott’s right, that’ll be wonderful—but that definitely isn’t where I would place my money.

    I think it’s very likely that 15 years from now, we will just then be measuring that dark energy is caused by this cosmological constant. We will be able to shrink the error bars and find that our present model still works.

    On dark matter, I think it’s much less clear. For a long time, the most popular candidate was this thing called the WIMP, or a Weakly Interacting Massive Particle. That idea is still popular and totally possible, but a lot of the particles that could be that kind of dark matter are already ruled out. The other really compelling candidate is a subatomic particle called the axion. People are just getting to a place where they’re able to start searching for these particles that we think are going to be extremely difficult to detect. It’s also possible that dark matter might surprise us, that it’s some new kind of particle that we don’t have the techniques to look for yet.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Kavli IPMU (Kavli Institute for the Physics and Mathematics of the Universe) is an international research institute with English as its official language. The goal of the institute is to discover the fundamental laws of nature and to understand the Universe from the synergistic perspectives of mathematics, astronomy, and theoretical and experimental physics. The Institute for the Physics and Mathematics of the Universe (IPMU) was established in October 2007 under the World Premier International Research Center Initiative (WPI) of the Ministry of Education, Sports, Science and Technology in Japan with the University of Tokyo as the host institution. IPMU was designated as the first research institute within the University of Tokyo Institutes for Advanced Study (UTIAS) in January 2011. It received an endowment from The Kavli Foundation and was renamed the “Kavli Institute for the Physics and Mathematics of the Universe” in April 2012. Kavli IPMU is located on the Kashiwa campus of the University of Tokyo, and more than half of its full-time scientific members come from outside Japan. http://www.ipmu.jp/
    The Kavli Foundation, based in Oxnard, California, is dedicated to the goals of advancing science for the benefit of humanity and promoting increased public understanding and support for scientists and their work.

    The Foundation’s mission is implemented through an international program of research institutes, professorships, and symposia in the fields of astrophysics, nanoscience, neuroscience, and theoretical physics as well as prizes in the fields of astrophysics, nanoscience, and neuroscience.

     
  • richardmitnick 12:01 pm on July 17, 2018 Permalink | Reply
    Tags: , Dark Matter Research, , ,   

    From Science and Technology Facilities Council via Lawrence Berkeley National Lab: “UK delivers super-cool kit to USA for Next-Generation Dark Matter Experiment” 


    From Science and Technology Facilities Council

    via

    Berkeley Logo

    From Lawrence Berkeley National Lab

    17 July 2018
    Jake Gilmore
    jake.gilmore@stfc.ac.uk

    A huge UK built titanium chamber designed to keep its contents at a cool -100C and weighing as much as an SUV has been shipped to the United States, where it will soon become part of a next-generation dark matter detector to hunt for the long-theorised elusive dark matter particle called a WIMP (Weakly Interacting Massive Particle).

    This hunt is important because the nature of dark matter, which physicists describe as the invisible component or ‘missing mass’ in the universe, has eluded scientists since its existence was deduced by Swiss astronomer Fritz Zwicky in 1933. The quest to find out what dark matter is made of, or whether it can be explained by tweaking the known laws of physics, is considered one of the most pressing questions in particle physics, on a par with the previous hunt for the Higgs boson.

    The cryostat chamber was built by a team of engineers at the UK’s Science and Technology Facilities Council’s Rutherford Appleton Laboratory in Oxfordshire, and journeyed around the world to the LUX-Zeplin (LZ) experiment, located 1400m underground at the Sanford Underground Research Facility (SURF) in South Dakota.

    LBNL Lux Zeplin project at SURF

    1
    A worker inspects the titanium cryostat for the LUX-ZEPLIN experiment in a clean room. (Credit: Matt Kapust/SURF)

    After being delivered to the surface facility at SURF the Outer Cryostat Vessel (OCV) of the cryostat chamber spent five weeks being fully assembled and leak checked in the SURF Assembly Lab (SAL) clean room. It has now been disassembled and packaged for transportation from the surface to the underground location at SURF. Meanwhile the Inner Cryostat Vessel is now in the SAL clean room getting prepared for the leak tests.

    STFC’s Dr Pawel Majewski, technical lead for the cryostat, said: “The cryostat was a feat of engineering with some very stringent and challenging requirements to meet. Because of the huge mass of the cryostat – 2,000kgs – we had to make sure it was made of ultra radio-pure titanium. It took nearly two years to find a pure enough sample to work with. Eventually we got it from one of the world’s leading titanium suppliers in the US where Electron Beam Cold Heart technology was used to melt the titanium.

    “This type of ultra-pure titanium is used, for example, in the healthcare industry to fabricate a pacemaker encapsulation. In our case it is used to hold the heart of the experiment.”

    It took two-and-a-half years to design the specialist equipment, and another two years to build in Italy by a company specialising in vessels and pipes fabrication only from titanium.

    The cryostat is a vital part of LZ, as it keeps the detector at freezing temperatures. This is crucial because the detector uses xenon – which at room temperature is a gas. But for the experiment to work, the xenon, which itself has low background radiation, must be kept in a liquid state, which is only achievable at around -100C.

    LZ is the latest experiment to hunt for the long-theorised elusive dark matter particle called a WIMP (Weakly Interacting Massive Particle). Many scientists believe finding WIMPs will provide the answer to one of the most pressing questions in physics – what is dark matter? WIMPS are thought to make up the most of dark matter – the as-yet-unknown substance which makes up about 85% of the universe. But because WIMPs are thought not to interact with normal matter, they are practically invisible using traditional detection methods.

    Liquid xenon emits a flash of light when struck by a particle, and this light can be detected by very sensitive photon detectors called photomultiplier tubes. If a WIMP collides with a xenon nucleus we expect it to produce a burst of light.

    Before delivery to SURF the cryostat underwent several weeks of rigorous testing and a month-long thorough clean from an expert cleaning company in California. Five years after the design efforts started, the cryostat arrived safely at SURF and the LZ team then carefully unwrapped it and put it into place.

    “It’s a great experience to see all of the planning for LZ paying off with the arrival of components,” said Murdock “Gil” Gilchriese, LZ project director and a Berkeley Lab physicist. “We look forward to seeing these components fully assembled and installed underground in preparation for the start of LZ science.”

    UK PI for LZ is Professor Henrique Araujo from Imperial College London and he said: “It is incredibly gratifying to see LZ beginning to take shape. Seeing the cryostat arrive is a milestone moment as it has been years in the making.

    “Now we have to wait for the other constituent elements to arrive before we can start to see some exciting science taking place at this ground-breaking facility.”

    LZ will be at least 100 times more sensitive to finding signals from dark matter particles than its predecessor, the Large Underground Xenon experiment (LUX). The new experiment will use 10 metric tons of ultra-purified liquid xenon, to tease out possible dark matter signals. Xenon, in its gas form, is one of the rarest elements in Earth’s atmosphere.

    Although this is a major milestone for the experiment, there are still many components yet to be assembled and tested. Upgrades of the underground Davis cavern at SURF, where LZ will be installed, are in progress and will be completed by August and large acrylic tanks that will help to validate LZ measurements are expected to arrive at SURF by September. It is currently expected that the experiment will start taking data in 2020.

    The U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) is leading the LZ project, which is expected to be completed in 2020. About 200 scientists and engineers from 39 institutions around the globe are part of the LZ collaboration.

    Since the project’s inception in 2012, STFC has been in charge of the design and the delivery of the cryostat. The engineering effort has been led by Joseph Saba, a Berkeley Lab mechanical engineer, and Edward Holtom of STFC’s Technology Department.

    Majewski said, “The cryostat was a feat of engineering, with some very stringent and challenging requirements. Because of its huge mass (about 2.2 tons), we had to make sure it was made of ultrapure titanium or it would overwhelm the detector with background radiation. It took more than two years to find titanium pure enough to work with.”

    He added, “This type of ultrapure titanium is used, for example, in the health care industry to fabricate pacemaker encapsulations. In our case it is used to hold the heart of the experiment.”

    The cryostat is the U.K.’s largest contribution to LZ but is not the only contribution. STFC is also supporting work on LZ’s calibration hardware, photomultiplier tubes, internal monitoring sensors, and materials screening, and is supporting one of the LZ data centers.

    Professor Henrique Araújo of Imperial College London, who is the U.K.’s principal investigator for LZ, said, “It is incredibly gratifying to see LZ beginning to take shape. Seeing the cryostat arrive is a milestone moment as it has been years in the making. This is the first big piece around which we will build the rest of the experiment.”

    There are still many LZ components yet to be assembled and tested. The experiment is expected to start taking data in 2020.

    Upgrades of the underground Davis cavern at SURF, where LZ will be installed, are in progress and will be completed by August, Gilchriese said, and large acrylic tanks that will help to validate LZ measurements are expected to arrive at SURF by September.

    Major support for LZ comes from the DOE Office of Science, the South Dakota Science and Technology Authority, the UK’s Science & Technology Facilities Council, and by collaboration members in South Korea and Portugal.

    See the full STFC article here.
    See the full LBNL article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    STFC Hartree Centre

    Helping build a globally competitive, knowledge-based UK economy

    We are a world-leading multi-disciplinary science organisation, and our goal is to deliver economic, societal, scientific and international benefits to the UK and its people – and more broadly to the world. Our strength comes from our distinct but interrelated functions:

    Universities: we support university-based research, innovation and skills development in astronomy, particle physics, nuclear physics, and space science
    Scientific Facilities: we provide access to world-leading, large-scale facilities across a range of physical and life sciences, enabling research, innovation and skills training in these areas
    National Campuses: we work with partners to build National Science and Innovation Campuses based around our National Laboratories to promote academic and industrial collaboration and translation of our research to market through direct interaction with industry
    Inspiring and Involving: we help ensure a future pipeline of skilled and enthusiastic young people by using the excitement of our sciences to encourage wider take-up of STEM subjects in school and future life (science, technology, engineering and mathematics)

    We support an academic community of around 1,700 in particle physics, nuclear physics, and astronomy including space science, who work at more than 50 universities and research institutes in the UK, Europe, Japan and the United States, including a rolling cohort of more than 900 PhD students.

    STFC-funded universities produce physics postgraduates with outstanding high-end scientific, analytic and technical skills who on graduation enjoy almost full employment. Roughly half of our PhD students continue in research, sustaining national capability and creating the bedrock of the UK’s scientific excellence. The remainder – much valued for their numerical, problem solving and project management skills – choose equally important industrial, commercial or government careers.

    Our large-scale scientific facilities in the UK and Europe are used by more than 3,500 users each year, carrying out more than 2,000 experiments and generating around 900 publications. The facilities provide a range of research techniques using neutrons, muons, lasers and x-rays, and high performance computing and complex analysis of large data sets.

    They are used by scientists across a huge variety of science disciplines ranging from the physical and heritage sciences to medicine, biosciences, the environment, energy, and more. These facilities provide a massive productivity boost for UK science, as well as unique capabilities for UK industry.

    Our two Campuses are based around our Rutherford Appleton Laboratory at Harwell in Oxfordshire, and our Daresbury Laboratory in Cheshire – each of which offers a different cluster of technological expertise that underpins and ties together diverse research fields.

    The combination of access to world-class research facilities and scientists, office and laboratory space, business support, and an environment which encourages innovation has proven a compelling combination, attracting start-ups, SMEs and large blue chips such as IBM and Unilever.

    We think our science is awesome – and we know students, teachers and parents think so too. That’s why we run an extensive Public Engagement and science communication programme, ranging from loans to schools of Moon Rocks, funding support for academics to inspire more young people, embedding public engagement in our funded grant programme, and running a series of lectures, travelling exhibitions and visits to our sites across the year.

    Ninety per cent of physics undergraduates say that they were attracted to the course by our sciences, and applications for physics courses are up – despite an overall decline in university enrolment.

     
  • richardmitnick 3:58 pm on November 1, 2017 Permalink | Reply
    Tags: , , , , , Dark Matter Research, , Physicists describe new dark matter detection strategy,   

    From Brown: “Physicists describe new dark matter detection strategy” 

    Brown University
    Brown University

    November 1, 2017
    Kevin Stacey
    401-863-3766

    Physicists from Brown University have devised a new strategy for directly detecting dark matter, the elusive material thought to account for the majority of matter in the universe.

    1
    Superfluid dark matter catcher
    A proposed dark matter detector using superfluid helium might detect particles with much lower mass than most current detectors.
    Maris/Seidel/Stein/Brown University

    The new strategy, which is designed to detect interactions between dark matter particles and a tub of superfluid helium, would be sensitive to particles in a much lower mass range than is possible with any of the large-scale experiments run so far, the researchers say.

    “Most of the large-scale dark matter searches so far have been looking for particles with a mass somewhere between 10 and 10,000 times the mass of a proton,” said Derek Stein, a physicist who co-authored the work with two of his Brown University colleagues, Humphrey Maris and George Seidel. “Below 10 proton masses, these experiments start to lose their sensitivity. What we want to do is extend sensitivity down in mass by three or four orders of magnitude and explore the possibility of dark matter particles that are much lighter.”

    A paper describing the new detector is published in Physical Review Letters.

    Missing matter

    Though it has not yet been detected directly, physicists are fairly certain that dark matter must exist in some form. The way in which galaxies rotate and the degree to which light bends as it travels through the universe suggest that there’s some kind of unseen stuff throwing its gravity around.

    The leading idea for the nature of dark matter is that it’s some kind of particle, albeit one that interacts very rarely with ordinary matter. But nobody is quite sure what a dark matter particle’s properties might be because nobody has yet recorded one of those rare interactions.

    There’s been good reason, Stein says, to search in the mass range where most dark matter experiments have focused thus far. A particle in that mass range would tie up a lot of loose theoretical ends. For example, the theory of supersymmetry — the idea that all the common particles we know and love have hidden partner particles — predicts dark matter candidates of the order of hundreds of proton masses.

    But the no-show of those particles in experiments so far has some physicists thinking about how to look elsewhere. This has led theorists to propose models in which dark matter would have much lower mass.

    A new approach

    The detection strategy that the Brown researchers have come up with involves a tub of superfluid helium. The idea is that dark matter particles passing through the tub should, on very rare occasions, smack into the nucleus of a helium atom. That collision would produce phonons and rotons — tiny excitations roughly similar to sound waves — which propagate with no loss of kinetic energy inside the superfluid. When those excitations reach the surface of the fluid, they’ll cause helium atoms to be released into a vacuum space above the surface. The detection of those released atoms would be the signal that a dark matter interaction has taken place in the tub.

    “The last bit is the tricky part,” said Maris, who has worked on similar helium-based detection schemes for other particles like solar neutrinos. The collision of a low-mass dark matter particle might result in only a single atom being released from the surface. That single atom would carry only about one milli-electron volt of energy, making it virtually impossible to detect through any traditional means. The novelty of this new detection scheme is a means to amplify that tiny, single-atom energy signature.

    It works by generating an electric field in the vacuum space above the liquid using an array of small, positively charged metal pins. As an atom released from the helium surface draws close to a pin, the positively charged tip will steal an electron from it, creating a positively charged helium ion. That newly created positive ion would be in close proximity to the positively charged pin, and because like charges repel each other, the ion will fly off with enough energy to be easily detectable by a standard calorimeter, a device that detects a temperature change when a particle runs into it.

    “If we put 10,000 volts on those little pins, then that ion going is going to fly away with 10,000 volts on it,” Maris said. “So it’s this ionization feature that gives us a new way to detect just the single helium atom that could be associated with a dark matter interaction.”

    Sensitive at low mass

    This new kind of detector wouldn’t be the first to use the tub-of-liquid-gas idea. The recently completed Large Underground Xenon (LUX) experiment and its successor, LUX-ZEPLIN, both use tubs of xenon gas. Using helium instead provides an important advantage in looking for particles with lower mass, the researchers say.

    For a collision to be detectable, the incoming particle and the target atomic nuclei must be of compatible mass. If the incoming particle is much smaller in mass than the target nuclei, any collision would result in the particle simply bouncing off without leaving a trace. Since LUX and L-Z are intended for the detection of particles with mass greater than five times that of a proton, they used xenon, which has a nucleus of around 100 proton masses. Helium has a nuclear mass only four times that of a proton, making a more compatible target for particles with much less mass.

    But even more important than the light target, the researchers say, is the ability of the new scheme to detect only a single atom evaporated from the helium surface. That kind of sensitivity would enable the device to detect the tiny amounts of energy deposited in the detector by particles with very small masses. The Brown team thinks its device would be sensitive to masses down to about twice the mass of an electron, roughly 1,000 to 10,000 times lighter than the particles detectable in large-scale dark matter experiments so far.

    Stein says that the first steps in actually making such a detector a reality will be fundamental experiments to better understand aspects of what’s happening in the superfluid helium and the precise dynamics of the ionization scheme.

    “From those fundamental experiments,” Stein says, “we would craft designs for a bigger and more complete dark matter experiment.”

    The research was funded in part by the National Science Foundation (DMR-1505044).

    See the full article here .

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    Welcome to Brown

    Brown U Robinson Hall
    Located in historic Providence, Rhode Island and founded in 1764, Brown University is the seventh-oldest college in the United States. Brown is an independent, coeducational Ivy League institution comprising undergraduate and graduate programs, plus the Alpert Medical School, School of Public Health, School of Engineering, and the School of Professional Studies.

    With its talented and motivated student body and accomplished faculty, Brown is a leading research university that maintains a particular commitment to exceptional undergraduate instruction.

    Brown’s vibrant, diverse community consists of 6,000 undergraduates, 2,000 graduate students, 400 medical school students, more than 5,000 summer, visiting and online students, and nearly 700 faculty members. Brown students come from all 50 states and more than 100 countries.

    Undergraduates pursue bachelor’s degrees in more than 70 concentrations, ranging from Egyptology to cognitive neuroscience. Anything’s possible at Brown—the university’s commitment to undergraduate freedom means students must take responsibility as architects of their courses of study.

     
  • richardmitnick 3:49 pm on October 26, 2017 Permalink | Reply
    Tags: , , , , Dark Matter Research, , ,   

    From The Conversation: “Dark matter: The mystery substance physics still can’t identify that makes up the majority of our universe” 

    FNAL II photo

    Fermilab

    Conversation
    The Conversation

    10.25.17
    Dan Hooper

    1
    Astronomers map dark matter indirectly, via its gravitational pull on other objects. NASA, ESA, and D. Coe (NASA JPL/Caltech and STScI), CC BY

    The past few decades have ushered in an amazing era in the science of cosmology. A diverse array of high-precision measurements has allowed us to reconstruct our universe’s history in remarkable detail.

    And when we compare different measurements – of the expansion rate of the universe, the patterns of light released in the formation of the first atoms, the distributions in space of galaxies and galaxy clusters and the abundances of various chemical species – we find that they all tell the same story, and all support the same series of events.

    This line of research has, frankly, been more successful than I think we had any right to have hoped. We know more about the origin and history of our universe today than almost anyone a few decades ago would have guessed that we would learn in such a short time.

    But despite these very considerable successes, there remains much more to be learned. And in some ways, the discoveries made in recent decades have raised as many new questions as they have answered.

    One of the most vexing gets at the heart of what our universe is actually made of. Cosmological observations have determined the average density of matter in our universe to very high precision. But this density turns out to be much greater than can be accounted for with ordinary atoms.

    After decades of measurements and debate, we are now confident that the overwhelming majority of our universe’s matter – about 84 percent – is not made up of atoms, or of any other known substance. Although we can feel the gravitational pull of this other matter, and clearly tell that it’s there, we simply do not know what it is. This mysterious stuff is invisible, or at least nearly so. For lack of a better name, we call it “dark matter.” But naming something is very different from understanding it.

    For almost as long as we’ve known that dark matter exists, physicists and astronomers have been devising ways to try to learn what it’s made of. They’ve built ultra-sensitive detectors, deployed in deep underground mines, in an effort to measure the gentle impacts of individual dark matter particles colliding with atoms.

    They’ve built exotic telescopes – sensitive not to optical light but to less familiar gamma rays, cosmic rays and neutrinos – to search for the high-energy radiation that is thought to be generated through the interactions of dark matter particles.

    And we have searched for signs of dark matter using incredible machines which accelerate beams of particles – typically protons or electrons – up to the highest speeds possible, and then smash them into one another in an effort to convert their energy into matter. The idea is these collisions could create new and exotic substances, perhaps including the kinds of particles that make up the dark matter of our universe.

    As recently as a decade ago, most cosmologists – including myself – were reasonably confident that we would soon begin to solve the puzzle of dark matter. After all, there was an ambitious experimental program on the horizon, which we anticipated would enable us to identify the nature of this substance and to begin to measure its properties. This program included the world’s most powerful particle accelerator – the Large Hadron Collider – as well as an array of other new experiments and powerful telescopes.

    LHC

    CERN/LHC Map

    CERN LHC Tunnel

    CERN LHC particles

    2
    Experiments at CERN are trying to zero in on dark matter – but so far no dice. CERN, CC BY-ND

    But things did not play out the way that we expected them to. Although these experiments and observations have been carried out as well as or better than we could have hoped, the discoveries did not come.

    Over the past 15 years, for example, experiments designed to detect individual particles of dark matter have become a million times more sensitive, and yet no signs of these elusive particles have appeared. And although the Large Hadron Collider has by all technical standards performed beautifully, with the exception of the Higgs boson, no new particles or other phenomena have been discovered.

    3
    At Fermilab, the Cryogenic Dark Matter Search uses towers of disks made from silicon and germanium to search for particle interactions from dark matter. Reidar Hahn/Fermilab, CC BY

    The stubborn elusiveness of dark matter has left many scientists both surprised and confused. We had what seemed like very good reasons to expect particles of dark matter to be discovered by now. And yet the hunt continues, and the mystery deepens.

    In many ways, we have only more open questions now than we did a decade or two ago. And at times, it can seem that the more precisely we measure our universe, the less we understand it. Throughout the second half of the 20th century, theoretical particle physicists were often very successful at predicting the kinds of particles that would be discovered as accelerators became increasingly powerful. It was a truly impressive run.

    But our prescience seems to have come to an end – the long-predicted particles associated with our favorite and most well-motivated theories have stubbornly refused to appear. Perhaps the discoveries of such particles are right around the corner, and our confidence will soon be restored. But right now, there seems to be little support for such optimism.

    In response, droves of physicists are going back to their chalkboards, revisiting and revising their assumptions. With bruised egos and a bit more humility, we are desperately attempting to find a new way to make sense of our world.

    See the full article here .

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    The Conversation US launched as a pilot project in October 2014. It is an independent source of news and views from the academic and research community, delivered direct to the public.
    Our team of professional editors work with university and research institute experts to unlock their knowledge for use by the wider public.
    Access to independent, high quality, authenticated, explanatory journalism underpins a functioning democracy. Our aim is to promote better understanding of current affairs and complex issues. And hopefully allow for a better quality of public discourse and conversation.

     
  • richardmitnick 10:48 am on October 17, 2017 Permalink | Reply
    Tags: Carleton U, Dark Matter Research, DEAP-3600 experiment, Ottawa Citizen,   

    From Carleton U via Ottawa Citizen: “Dark matter: Carleton physicist gets $3.35M to help unravel mysteries of the universe” 

    Carleton University
    1
    Carleton University experimental physicist Mark Boulay has been warded $3.35 million for a new lab. Tony Caldwell

    A Carleton University experimental physicist has been awarded $3.35 million to build a lab to help gain insight into the nature of neutrinos and dark matter. The elusive answers to those questions could lead to nothing less than a better understanding of how the universe was formed.

    Neutrinos are much smaller than other known particles, and are very difficult to detect. The actually mass of the neutrino is not known. A measurement that would shed light on its mass and the origin of that mass would offer some insight into the formation of the universe.

    Dark matter is even more mysterious.

    Dark Matter Research

    Universe map Sloan Digital Sky Survey (SDSS) 2dF Galaxy Redshift Survey

    Scientists studying the cosmic microwave background hope to learn about more than just how the universe grew—it could also offer insight into dark matter, dark energy and the mass of the neutrino.

    Dark matter cosmic web and the large-scale structure it forms The Millenium Simulation, V. Springel et al

    Dark Matter Particle Explorer China

    DEAP Dark Matter detector, The DEAP-3600, suspended in the SNOLAB deep in Sudbury’s Creighton Mine

    LUX Dark matter Experiment at SURF, Lead, SD, USA

    ADMX Axion Dark Matter Experiment, U Uashington

    It has never been observed, but scientists have known for a long time that it’s out there because its gravitational effects can be seen — galaxies move faster than expected, for example.

    Dark matter outweighs conventional matter by five-to-one, said Mark Boulay, who is the Canada Research Chair in Particle Astrophysics and Subatomic Physics. Essentially, most of the matter in the universe is invisible.

    “There’s a large amount of mass that goes unaccounted for. We know that there’s matter out there, but we haven’t directly seen it,” he said.

    The $3.35 million in funding from the Canada Foundation for Innovation will be used to develop and build detectors that use liquified noble gases to identify extremely rare subatomic processes.

    Boulay has been leading the DEAP-3600 experiment in SNOLAB, an underground laboratory in a mine two kilometres under the surface of the earth near Sudbury.

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

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

    One hypothesis suggests that dark matter consists of Weakly Interacting Massive Particles, known as WIMPs. The rock overburden at SNOLAB filters out cosmic rays that would interfere with WIMP detection. The DEAP-3600 experiments searches for dark matter particle interactions using a detector containing 3,600 kilograms of liquid argon.

    Dark matter research is one of the highest-profile areas of particle physics — and it’s highly competitive. The detectors being developed for the Carleton lab will support the study of neutrinos and dark matter at SNOLAB. The lab will be used by researchers at Carleton and others in its network, which includes TRIUMF, Canada’s national laboratory for particle and nuclear physics, as well as the University of British Columbia, McGill University and Université de Sherbrooke.

    “In my field we’ve been looking to demonstrate conclusively the existence of this particle. We’ve been looking for two or three decades. We haven’t found it yet. We don’t know what the mass of the particle is, or how likely it is to interact with other matter,” said Boulay. “We understand that we have a lot of work ahead of us.”

    He estimates it will take a year to construct the first set of prototype detectors for the lab at Carleton. The lab will occupy about 2,000 square feet of space in the Herzberg building.

    “We want to be able to define future programs — what detectors we will be able to build in the next 20 years,” said Boulay. “We’re at the leading edge of what’s possible, and we want to push that.”

    See the full article here .

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    Situated on unceded Algonquin territory beside the historic Rideau Canal, an official UNESCO World Heritage Site, Carleton University was founded by the community in 1942 to meet the needs of veterans returning from the Second World War.

    What defines Carleton?

    We strive for innovation in research, teaching and learning.
    Our location in Ottawa, the nation’s capital, connects us to the world.
    We encourage hands-on experience in the classroom.
    We offer exceptional student support.

     
  • richardmitnick 4:00 pm on August 1, 2017 Permalink | Reply
    Tags: Dark Matter Research, , , Surface lab cleanroom paves way for LZ assembly   

    From SURF: “Surface lab cleanroom paves way for LZ assembly” 

    SURF logo
    Sanford Underground levels

    Sanford Underground Research facility

    July 31, 2017
    Christel Peters

    1
    The surface laboratory cleanroom. Matt Kapust.

    After years of planning, building and installing systems, Sanford Lab’s cleanroom is, well, really clean, paving the way for the LUX-ZEPLIN collaboration to begin assembling the second-generation dark matter experiment.

    Lux Zeplin project at SURF

    “Now that construction is complete and we have done a first round of extensive cleaning of all surfaces, we are taking careful measurements of the degree of cleanliness and radon concentration in the air,” said Simon Fiorucci, a member of the LZ collaboration. “This will take several more weeks until we are convinced of the room’s performance. We expect to receive the first LZ detector parts to start assembly by the end of the year.”

    At the same time the cleanroom was under construction, Sanford Lab was building a new radon-reduction facility. That building was completed and equipped earlier this summer. Radon, a naturally occurring radioactive gas, significantly increases background noise in sensitive physics projects. The radon reduction system pressurizes, dehumidifies and cools air to minus 60 degrees Celsius before sending it through two columns, each filled with 1600 kg of activated charcoal, which remove the radon. The pressure is released, warmed and humidified before flowing into the cleanroom.

    “That’s the magic part of this cleanroom,” said John Keefner, underground operations engineer and project manager for the cleanroom construction.. “The room will be positively pressured so radon can’t get in.”

    Creating a clean space for scientists requires more than dust rags and vacuum cleaners. Robyn Varland, custodian for the Davis Campus, and Melissa Barker, a contract custodian from The CleanerZ, worked diligently to remove the visible—and unseen—particles that lingered on the surfaces of the room. The other systems that maintain a clean environment are also in place and functioning; the radon-reduction, water purification and air filtration systems.

    “It took about 80 hours to clean and we worked at it hard,” Varland said. “It just takes time, you can’t ‘go clean’ fast.”

    Varland uses the same system that is in place for the Majorana Demonstrator cleanroom.

    U Washington Majorana Demonstrator Experiment at SURF

    In the Surface Lab cleanroom, Varland and Barker spent seven hours just on the grating. “That was the hardest part,” Varland said. “Each bar was vacuumed and washed thoroughly with a wet rag and scrubbing tool to lift the particulates. Spray, wipe with a rag, rinse it out three times.”

    And it’s all done moving only half-an-arm-length at a time—all while suited up in cleanroom garb to prevent any contamination.

    “Once the initial cleaning happens, you then become the source of dust,” said David Taylor, experiment review engineer for LZ. “That requires special PPE and procedures to keep it clean. Now, the particle counts are really low. That means the dust is gone and it’s ready to use.”

    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.
    LUX/Dark matter experiment at SURFLUX/Dark matter experiment 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.

    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.

    Fermilab LBNE
    LBNE

     
  • richardmitnick 10:22 pm on July 15, 2017 Permalink | Reply
    Tags: , , Dark Matter Research, , , , , MEET SURF, , , , U Washington Majorana   

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

    SURF logo
    Sanford Underground levels

    THIS POST IS DEDICATED TO CONSTANCE WALTER, Communications Director, fantastic writer, AND MATT KAPUST Creative Services Developer, master photogropher, FOR THEIR TIRELESS EFFORTS IN KEEPING US INFORMED ABOUT PROGRESS FOR SCIENCE IN SOUTH DAKOTA, USA.

    Sanford Underground Research facility

    The SURF story in pictures:

    SURF-Sanford Underground Research Facility


    SURF Above Ground

    SURF Out with the Old


    SURF An Empty Slate


    SURF Carving New Space


    SURF Shotcreting


    SURF Bolting and Wire Mesh


    SURF Outfitting Begins


    SURF circular wooden frame was built to form a concrete ring to hold the 72,000-gallon (272,549 liters) water tank that would house the LUX dark matter detector


    SURF LUX water tank was transported in pieces and welded together in the Davis Cavern


    SURF Ground Support


    SURF Dedicated to Science


    SURF Building a Ship in a Bottle


    SURF Tight Spaces


    SURF Ready for Science


    SURF Entrance Before Outfitting


    SURF Entrance After Outfitting


    SURF Common Corridior


    SURF Davis


    SURF Davis A World Class Site


    SURF Davis a Lab Site


    SURF DUNE LBNF Caverns at Sanford Lab


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


    FNAL DUNE Argon tank at SURF

    U Washington LUX Xenon experiment at SURF


    SURF Before Majorana


    U Washington Majorana Demonstrator Experiment at SURF

    This is the full article here .

    Please help promote STEM in your local schools.
    STEM Icon

    Stem Education Coalition

    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.
    LUX/Dark matter experiment at SURFLUX/Dark matter experiment 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.

    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.

    Fermilab LBNE
    LBNE

     
  • richardmitnick 1:51 pm on June 20, 2017 Permalink | Reply
    Tags: , , , , Dark Matter Research, Micro-X rocket experiment—an X-ray space telescope,   

    From Symmetry: “A speed trap for dark matter, revisited” 

    Symmetry Mag

    Symmetry

    06/20/17
    Manuel Gnida

    1
    NASA, JPL-Caltech, Susan Stolovy (SSC/Caltech) et al.

    A NASA rocket experiment could use the Doppler effect to look for signs of dark matter in mysterious X-ray emissions from space.

    Researchers who hoped to look for signs of dark matter particles in data from the Japanese ASTRO-H/Hitomi satellite suffered a setback last year when the satellite malfunctioned and died just a month after launch.

    JAXA Hitomi ASTRO-H instruments

    Now the idea may get a second chance.

    In a new paper, published in Physical Review D, scientists from the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), a joint institute of Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory, suggest that their novel search method could work just as well with the future NASA-funded Micro-X rocket experiment—an X-ray space telescope attached to a research rocket.

    2
    Micro-X rocket schematic. http://inspirehep.net/record/1258362/plots

    The search method looks for a difference in the Doppler shifts produced by movements of dark matter and regular matter, says Devon Powell, a graduate student at KIPAC and lead author on the paper with co-authors Ranjan Laha, Kenny Ng and Tom Abel.

    The Doppler effect is a shift in the frequency of sound or light as its source moves toward or away from an observer. The rising and falling pitch of a passing train whistle is a familiar example, and the radar guns that cops use to catch speeders also work on this principle.

    The dark matter search technique, called Dark Matter Velocity Spectroscopy, is like setting up a speed trap to “catch” dark matter.

    “We think that dark matter has zero averaged velocity, while our solar system is moving,” says Laha, who is a postdoc at KIPAC. “Due to this relative motion, the dark matter signal would experience a Doppler shift. However, it would be completely different than the Doppler shifts from signals coming from astrophysical objects because those objects typically co-rotate around the center of the galaxy with the sun, and dark matter doesn’t. This means we should be able to distinguish the Doppler signatures from dark and regular matter.”

    Researchers would look for subtle frequency shifts in measurements of a mysterious X-ray emission. This 3500-electronvolt (3.5 keV) emission line, observed in data from the European XMM-Newton spacecraft and NASA’s Chandra X-ray Observatory, is hard to explain with known astrophysical processes.

    ESA/XMM Newton

    NASA/Chandra Telescope

    Some say it could be a sign of hypothetical dark matter particles called sterile neutrinos decaying in space.

    “The challenge is to find out whether the X-ray line is due to dark matter or other astrophysical sources,” Powell says. “We’re looking for ways to tell the difference.”

    The idea for this approach is not new: Laha and others described the method in a research paper last year[Physical Review Letters], in which they suggested using X-ray data from Hitomi to do the Doppler shift comparison. Although the spacecraft sent some data home before it disintegrated, it did not see any sign of the 3.5-keV signal, casting doubt on the interpretation that it might be produced by the decay of dark matter particles. The Dark Matter Velocity Spectroscopy method was never applied, and the issue was never settled.

    In the future Micro-X experiment, a rocket will catapult a small telescope above Earth’s atmosphere for about five minutes to collect X-ray signals from a specific direction in the sky. The experiment will then parachute back to the ground to be recovered. The researchers hope that Micro-X will do several flights to set up a speed trap for dark matter.

    4
    Jeremy Stoller, NASA

    “We expect the energy shifts of dark matter signals to be very small because our solar system moves relatively slowly,” Laha says. “That’s why we need cutting-edge instruments with superb energy resolution. Our study shows that Dark Matter Velocity Spectroscopy could be successfully done with Micro-X, and we propose six different pointing directions away from the center of the Milky Way.”

    Esra Bulbul from the MIT Kavli Institute for Astrophysics and Space Research, who wasn’t involved in the study, says, “In the absence of Hitomi observations, the technique outlined for Micro-X provides a promising alternative for testing the dark matter origin of the 3.5-keV line.” But Bulbul, who was the lead author of the paper that first reported the mystery X-ray signal in superimposed data of 73 galaxy clusters, also points out that the Micro-X analysis would be limited to our own galaxy.

    The feasibility study for Micro-X is more detailed than the prior analysis for Hitomi. “The earlier paper used certain approximations—for instance, that the dark matter halos of galaxies are spherical, which we know isn’t true,” Powell says. “This time we ran computer simulations without this approximation and predicted very precisely what Micro-X would actually see.”

    The authors say their method is not restricted to the 3.5-keV line and can be applied to any sharp signal potentially associated with dark matter. They hope that Micro-X will do the first practice test. Their wish might soon come true.

    “We really like the idea presented in the paper,” says Enectali Figueroa-Feliciano, the principal investigator for Micro-X at Northwestern University, who was not involved in the study. “We would look at the center of the Milky Way first, where dark matter is most concentrated. If we saw an unidentified line and it were strong enough, looking for Doppler shifts away from the center would be the next step.”

    See the full article here .

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    Symmetry is a joint Fermilab/SLAC publication.


     
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