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  • richardmitnick 9:27 am on March 14, 2017 Permalink | Reply
    Tags: , Last but not least the poly shield, , , Neutrinos, ,   

    From SURF: “Last, but not least, the poly shield” 

    SURF logo
    Sanford Underground levels

    Sanford Underground Research facility

    March 13, 2017
    Constance Walter

    1
    Vince Guiseppe stands next to an extra lead brick monolith, which keeps the shield sealed if a working module needs to be removed for service. Credit: Constance Walter

    For nearly seven years, the Majorana Demonstrator Project’s “shield team” has been building the six-layered shield that surrounds the experiment on the 4850 Level. In early March, they placed the last piece of polyethylene on the outermost layer of the shield.

    “I’m proud of what the team has produced,” said Vince Guiseppe, assistant professor of physics at the University of South Carolina. “This was a complicated project. Every layer was added at the right time and fit perfectly.”


    U Washington Majorana Demonstrator Experiment

    The Majorana collaboration uses germanium crystals to look for a rare form of radioactive decay called neutrinoless double-beta decay. The discovery could determine whether the neutrino is its own antiparticle. Its detection could help explain why matter exists. The shield is critical to the success of the experiment.

    Each layer of the shield was designed to target certain forms of radiation. “The closer the layer is to the experiment, the greater its impact,” Guiseppe said.

    The most important layer is the electroformed copper that sits closest to the experiment. Comprised of 40, half-inch thick copper plates, it was grown and machined underground. “This is clearly the hallmark of our shield system in terms of purity and cleanliness protocols,” Guiseppe said. Surrounding that portion of the shield, is a 2-inch thick layer of ultrapure commercial copper.

    Next is a “castle” built with 3,400 lead bricks. Two portable monoliths, each holding 570 bricks, support the cryostats filled with strings of germanium detectors and cryogenic hardware, what Guiseppe calls “the heart of the experiment.”

    An aluminum box encapsulating the lead castle protects the experiment from naturally occurring radon. Every minute, the team injects eight liters of nitrogen gas to purge the air within the enclosure. “We don’t want any lab air getting in.”

    Attached to the aluminum box are scintillating plastic “veto panels” designed to detect muons, the most penetrating of all cosmic rays.

    Finally, there’s the 12 inches of polyethylene enclosing the entire experiment, including the cryogenics (chilled water heat exchangers moderate the temperature). The poly slows down neutrons that could cause very rare backgrounds. Why worry about such rare events? High-energy neutrons can bounce through just about anything, including the 22 inches of lead and copper shielding. If a neutron hits a copper atom, it could create a gamma ray right next to the experiment.

    “The poly is the final defense against backgrounds in an experiment that requires extreme quiet,” Guiseppe said.

    The entire shield, weighing 145,000 pounds, rests on an over floor made of steel with channels for the poly.

    Jared Thompson, a research assistant, began his work with Majorana in 2010, etching lead bricks for the shield. In fact, in March 2014, he placed the last brick on the castle. And he was part of the group that recently placed the last piece of poly.

    “It’s really exciting,” Thompson said. “A complete shield could mean a whole new data set down the road.”

    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 2:46 pm on March 7, 2017 Permalink | Reply
    Tags: CERN Proto Dune, , Neutrinos, Researchers face engineering puzzle, , , Transporting Argon   

    From Symmetry: “Researchers face engineering puzzle” 

    Symmetry Mag

    Symmetry

    03/07/17
    Daniel Garisto

    How do you transport 70,000 tons of liquid argon nearly a mile underground?


    FNAL DUNE Argon tank at SURF

    Nearly a mile below the surface of Lead, South Dakota, scientists are preparing for a physics experiment that will probe one of the deepest questions of the universe: Why is there more matter than antimatter?
    FNAL LBNF/DUNE from FNAL to SURF, Lead, South Dakota, USA


    SURF


    Surf-Dune/LBNF Caverns at Sanford Lab

    Because neutrinos interact with matter so rarely and so weakly, DUNE scientists need a lot of material to create a big enough target for the particles to run into. The most widely available (and cost effective) inert substance that can do the job is argon, a colorless, odorless element that makes up about 1 percent of the atmosphere.

    The researchers also need to place the detector full of argon far below Earth’s surface, where it will be protected from cosmic rays and other interference.

    “We have to transfer almost 70,000 tons of liquid argon underground,” says David Montanari, a Fermilab engineer in charge of the experiment’s cryogenics. “And at this point we have two options: We can either transfer it as a liquid or we can transfer it as a gas.”

    Either way, this move will be easier said than done.

    Liquid or gas?

    The argon will arrive at the lab in liquid form, carried inside of 20-ton tanker trucks. Montanari says the collaboration initially assumed that it would be easier to transport the argon down in its liquid form—until they ran into several speed bumps.

    Transporting liquid vertically is very different from transporting it horizontally for one important reason: pressure. The bottom of a mile-tall pipe full of liquid argon would have a pressure of about 3000 pounds per square inch—equivalent to 200 times the pressure at sea level. According to Montanari, to keep these dangerous pressures from occurring, multiple de-pressurizing stations would have to be installed throughout the pipe.

    Even with these depressurizing stations, safety would still be a concern. While argon is non-toxic, if released into the air it can reduce access to oxygen, much like carbon monoxide does in a fire. In the event of a leak, pressurized liquid argon would spill out and could potentially break its vacuum-sealed pipe, expanding rapidly to fill the mine as a gas. One liter of liquid argon would become about 800 liters of argon gas, or four bathtubs’ worth.

    Even without a leak, perhaps the most important challenge in transporting liquid argon is preventing it from evaporating into a gas along the way, according to Montanari.

    To remain a liquid, argon is kept below a brisk temperature of minus 180 degrees Celsius (minus 300 degrees Fahrenheit).

    “You need a vacuum-insulated pipe that is a mile long inside a mine shaft,” Montanari says. “Not exactly the most comfortable place to install a vacuum-insulated pipe.”

    To avoid these problems, the cryogenics team made the decision to send the argon down as gas instead.

    Routing the pipes containing liquid argon through a large bath of water will warm it up enough to turn it into gas, which will be able to travel down through a standard pipe. Re-condensers located underground act as massive air conditioners will then cool the gas until becomes a liquid again.

    “The big advantage is we no longer have vacuum insulated pipe,” Montanari says. “It is just straight piece of pipe.”

    Argon gas poses much less of a safety hazard because it is about 1000 times less dense than liquid argon. High pressures would be unlikely to build up and necessitate depressurizing stations, and if a leak occurred, it would not expand as much and cause the same kind of oxygen deficiency.

    The process of filling the detectors with argon will take place in four stages that will take almost two years, Montanari says. This is due to the amount of available cooling power for re-condensing the argon underground. There is also a limit to the amount of argon produced in the US every year, of which only so much can be acquired by the collaboration and transported to the site at a time.

    1
    Illustration by Ana Kova

    Argon for answers

    Once filled, the liquid argon detectors will pick up light and electrons produced by neutrino interactions.

    Part of what makes neutrinos so fascinating to physicists is their habit of oscillating from one flavor—electron, muon or tau—to another. The parameters that govern this “flavor change” are tied directly to some of the most fundamental questions in physics, including why there is more matter than antimatter. With careful observation of neutrino oscillations, scientists in the DUNE collaboration hope to unravel these mysteries in the coming years.

    “At the time of the Big Bang, in theory, there should have been equal amounts of matter and antimatter in the universe,” says Eric James, DUNE’s technical coordinator. That matter and antimatter should have annihilated, leaving behind an empty universe. “But we became a matter-dominated universe.”

    James and other DUNE scientists will be looking to neutrinos for the mechanism behind this matter favoritism. Although the fruits of this labor won’t appear for several years, scientists are looking forward to being able to make use of the massive detectors, which are hundreds of times larger than current detectors that hold only a few hundred tons of liquid argon.

    Currently, DUNE scientists and engineers are working at CERN to construct Proto-DUNE, a miniature replica of the DUNE detector filled with only 300 tons of liquid argon that can be used to test the design and components.


    CERN Proto DUNE Maximillian Brice

    “Size is really important here,” James says. “A lot of what we’re doing now is figuring out how to take those original technologies which have already being developed… and taking it to this next level with bigger and bigger detectors.”

    To search for that answer, the Deep Underground Neutrino Experiment, or DUNE, will look at minuscule particles called neutrinos. A beam of neutrinos will travel 800 miles through the Earth from Fermi National Accelerator Laboratory to the Sanford Underground Research Facility, headed for massive underground detectors that can record traces of the elusive particles.

    See the full article here .

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 9:35 pm on March 3, 2017 Permalink | Reply
    Tags: , Neutrinos, ,   

    From NC State via phys.org: “Calculations show close Ia supernova should be neutrino detectable offering possibility of identifying explosion type” 

    NC State bloc

    North Carolina State University

    phys.org

    phys.org

    1
    Density contour plots including deflagration (white) and detonation (green) surfaces. Credit: arXiv:1609.07403 [astro-ph.HE]

    A team of researchers at North Carolina State University has found that current and future neutrino detectors placed around the world should be capable of detecting neutrinos emitted from a relatively close supernova. They also suggest that measuring such neutrinos would allow them to explain what goes on inside of a star during such an explosion—if the measurements match one of two models that the team has built to describe the inner workings of a supernova.

    Supernovae have been classified into different types depending on what causes them to occur—one type, called a la supernova, occurs when a white dwarf pulls in enough material from a companion, eventually triggering carbon fusion, which leads to a massive explosion. Researchers here on Earth can see evidence of a supernova by the light that is emitted. But astrophysicists would really like to know more about the companion and the actual process that occurs inside the white dwarf leading up to the explosion—and they believe that might be possible by studying the neutrinos that are emitted.

    In this new effort, a team led by Warren Wright calculated that neutrinos from a relatively nearby supernova should be detectable by current sensors already installed and working around the planet and by those that are in the works. Wright also headed two teams that have each written a paper describing one of two types of models that the team has built to describe the process that occurs in the white dwarf leading up to the explosion—both teams have published their work in the journal Physical Review Letters.

    The first model is called the deflagration-to-detonation transition; the second, the gravitationally confined detonation. Both are based on theory regarding interactions inside of the star and differ mostly in how spherically symmetric they are. The two types would also emit different kinds and amounts of neutrinos, which is why the team is hoping that the detectors capable of measuring them will begin to do so. That would allow the teams to compare their models against real measurable data, and in so doing, perhaps finally offer some real evidence of what occurs when stars explode.

    See the full article here .

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    NC State campus

    NC State was founded with a purpose: to create economic, societal and intellectual prosperity for the people of North Carolina and the country. We began as a land-grant institution teaching the agricultural and mechanical arts. Today, we’re a pre-eminent research enterprise that excels in science, technology, engineering, math, design, the humanities and social sciences, textiles and veterinary medicine.

    NC State students, faculty and staff take problems in hand and work with industry, government and nonprofit partners to solve them. Our 34,000-plus high-performing students apply what they learn in the real world by conducting research, working in internships and co-ops, and performing acts of world-changing service. That experiential education ensures they leave here ready to lead the workforce, confident in the knowledge that NC State consistently rates as one of the best values in higher education.

     
  • richardmitnick 2:04 pm on February 23, 2017 Permalink | Reply
    Tags: , , Neutrinos,   

    From FNAL: “The global reach of DUNE” 

    FNAL II photo

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

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

    [This post is dedicated to LH, a writer whose work I dealy love, and CW, the voice of SURF]

    February 23, 2017

    Leah Hesla

    The neutrino, it would seem, has global appeal.

    The mysteries surrounding the renegade particle are attracting a worldwide science community to the future DUNE experiment. DUNE — the Deep Underground Neutrino Experiment — is a multinational effort to address the biggest questions in neutrino physics. More than 950 researchers from 30 countries have joined the DUNE collaboration, and both numbers are trending upward: Back in 2015, the collaboration comprised about 560 scientists and engineers from 23 countries.

    It’s currently the largest particle physics project being undertaken anywhere in the world since the Large Hadron Collider at the European laboratory CERN. Modeled after CERN’s ATLAS and CMS experiments, the DUNE collaboration is established as an international organization. The experiment will be hosted in the United States by Fermi National Accelerator Laboratory.

    The latest countries to join DUNE include Chile and Peru. The most recent new institutes to join DUNE come from Colombia, the UK and the US.

    “It’s the excitement that’s being generated by the science,” said DUNE spokesperson Mark Thomson, a professor of physics at the University of Cambridge in the UK. “Everybody recognizes the DUNE program as strong, and the technology is interesting as well.”

    Collaborators are developing new technologies for DUNE’s two particle detectors, giant instruments that will help capture the experiment’s notoriously elusive quarry, the neutrino.

    FNAL Dune/LBNF
    FNAL Dune/LBNF map

    With DUNE, which is expected to be up and running in the mid-2020s, scientists plan to get a better grip on the neutrino’s subtleties to settle the question of, for instance, why there’s more matter than antimatter in our universe — in other words, how the stars planets and life as we know it were able to form. Also on the DUNE agenda are studies that could bolster certain theories of the unification of all fundamental forces and, with the help of neutrinos born in supernovae, provide a look into the birth of a black hole.

    It’s a tall order that will take a global village to fill, and researchers worldwide are currently building the experiment or signing up to build it, taking advantage of DUNE’s broad scientific and geographic scope.

    “We’re a country that does a lot of theoretical physics but not a lot of experimental physics, because it’s not so cheap to have a particle physics experiment here,” said DUNE collaborator Ana Amelia Machado, a collaborating scientist at the University of Campinas and a professor at the Federal University of ABC in the ABC region of Brazil. “So we participate in big collaborations like DUNE, which is attractive because it brings together theorists and experimentalists.”

    Machado is currently working on a device named Arapuca, which she describes as a photon catcher that could detect particle phenomena that DUNE is interested in, such as supernova neutrino interactions. She’s also working to connect more Latin American universities with DUNE, adding the University Antonio Nariño to the list of DUNE institutions.

    On the opposite side of the world, scientists and engineers from India are working on upgrading the high intensity superconducting proton accelerator at Fermilab, which will provide the world’s most intense neutrino beam to the DUNE experiment. Building on the past collaborations with other Fermilab experiments, the Indian scientists are also proposing to build the near detector for the DUNE experiment. Not only are India’s contributions important for DUNE’s success, they’re also potential seeds for India’s own future particle physics programs.

    2
    More than 950 researchers from 30 countries have joined DUNE. Collaborators are developing new technologies for DUNE’s particle detectors, giant instruments that will help capture the notoriously elusive neutrino.

    “It’s exciting because it’s something that India’s doing for the first time. India has never built a full detector for any particle physics experiment in the world,” said Bipul Bhuyan, a DUNE collaborator at the Indian Institution of Technology Guwahati. “Building a particle detector for an international science experiment like DUNE will bring considerable visibility to Indian institutions and better industry-academia partnership in developing advanced detector technology. It will help us to build our own future experimental facility in India as well.”

    DUNE’s two particle detectors will be separated by 800 miles: a two-story detector on the Fermilab site in northern Illinois and a far larger detector to be situated nearly a mile underground in South Dakota at the Sanford Underground Research Facility.

    surf-building-in-lead-sd-usa
    SURF logo
    FNAL DUNE Argon tank at SURF
    DUNE Argon tank at SURF
    Sanford Underground levels
    Sanford Underground levels
    surf-dune-lbnf-caverns-at-sanford-lab
    Surf-Dune/LBNF Caverns at Sanford Lab

    Fermilab particle accelerators, part of the Long-Baseline Neutrino Facility for DUNE, will create an intense beam of neutrinos that will pass first through the near detector and then continue straight through Earth to the far detector.

    FNAL LBNF/DUNE Near Detector
    FNAL/DUNE Near Site Layout

    Scientists will compare measurements from the two detectors to examine how the neutrinos morphed from one of three types into another over their interstate journey. The far detector will contain 70,000 tons of cryogenic liquid argon to capture a tiny fraction of the neutrinos that pass through it. DUNE scientists are currently working on ways to improve liquid-argon detection techniques.

    The near detector, which is close to the neutrino beam source and so sees the beam where it is most intense, will be packed with all kinds of components so that scientists can get as many readings as they can on the tricky particles: their energy, their momentum, the likelihood that they’ll interact with the detector material.

    “This is an opportunity for new collaborators, where new international groups can get involved in a big way,” said Colorado State University professor Bob Wilson, chair of the DUNE Institutional Board. “There’s a broad scope of physics topics that will come out of the near detector.”

    As the collaboration expands, so too does the breadth of DUNE physics topics, and the more research opportunities there are, the more other institutions are likely to join the project.

    “There aren’t that many new, big experiments out there,” Thomson said. “We have 950 collaborators now, and we’re likely to hit 1,000 in the coming months.”

    That will be a notable milestone for the collaboration, one that follows another sign of its international strength: Late last month, for the first time, DUNE held its collaboration meeting away from its home base of Fermilab. CERN served as the meeting host.

    DUNE is supported by funding agencies from many countries, including the Department of Energy Office of Science in the United States.

    “We have people from different countries that haven’t been that involved in neutrino physics before and who bring different perspectives,” Wilson said. “It’s all driven by the interest in the science, and the breadth of interest has been tremendous.”

    See the full article here .

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    Fermilab Campus

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

     
  • richardmitnick 5:27 pm on February 21, 2017 Permalink | Reply
    Tags: A candidate for dark matter?, A mobile neutrino detector could be used to determine whether a nuclear reactor is in use, , Determine whether material from a reactor has been repurposed to produce nuclear weapons?, MiniCHANDLER is specifically designed to detect neutrinos' antimatter counterparts antineutrinos, MiniCHANDLER will make history as the first mobile neutrino detector in the US, Neutrinos, , Virginia Tech   

    From Symmetry: “Mobile Neutrino Lab makes its debut” 

    Symmetry Mag

    Symmetry

    02/21/17
    Daniel Garisto

    1
    The Mystery Machine for particles hits the road.

    It’s not as flashy as Scooby Doo’s Mystery Machine, but scientists at Virginia Tech hope that their new vehicle will help solve mysteries about a ghost-like phenomena: neutrinos.

    The Mobile Neutrino Lab is a trailer built to contain and transport a 176-pound neutrino detector named MiniCHANDLER (Carbon Hydrogen AntiNeutrino Detector with a Lithium Enhanced Raghavan-optical-lattice). When it begins operations in mid-April, MiniCHANDLER will make history as the first mobile neutrino detector in the US.

    “Our main purpose is just to see neutrinos and measure the signal to noise ratio,” says Jon Link, a member of the experiment and a professor of physics at Virginia Tech’s Center for Neutrino Physics. “We just want to prove the detector works.”

    Neutrinos are fundamental particles with no electric charge, a property that makes them difficult to detect. These elusive particles have confounded scientists on several fronts for more than 60 years. MiniCHANDLER is specifically designed to detect neutrinos’ antimatter counterparts, antineutrinos, produced in nuclear reactors, which are prolific sources of the tiny particles.

    Fission at the core of a nuclear reactor splits uranium atoms, whose products themselves undergo a process that emits an electron and electron antineutrino. Other, larger detectors such as Daya Bay have capitalized on this abundance to measure neutrino properties.

    MiniCHANDLER will serve as a prototype for future mobile neutrino experiments up to 1 ton in size.

    Link and his colleagues hope MiniCHANDLER and its future counterparts will find answers to questions about sterile neutrinos, an undiscovered, theoretical kind of neutrino and a candidate for dark matter. The detector could also have applications for national security by serving as a way to keep tabs on material inside of nuclear reactors.

    MiniCHANDLER echoes a similar mobile detector concept from a few years ago. In 2014, a Japanese team published results from another mobile neutrino detector, but their data did not meet the threshold for statistical significance. Detector operations were halted after all reactors in Japan were shut down for safety inspections.

    “We can monitor the status from outside of the reactor buildings thanks to [a] neutrino’s strong penetration power,” Shugo Oguri, a scientist who worked on the Japanese team, wrote in an email.

    Link and his colleagues believe their design is an improvement, and the hope is that MiniCHANDLER will be able to better reject background events and successfully detect neutrinos.

    Neutrinos, where are you?

    To detect neutrinos, which are abundant but interact very rarely with matter, physicists typically use huge structures such as Super-Kamiokande, a neutrino detector in Japan that contains 50,000 tons of ultra-pure water.

    Super-Kamiokande Detector, Japan
    Super-Kamiokande Detector, Japan

    Experiments are also often placed far underground to block out signals from other particles that are prevalent on Earth’s surface.

    With its small size and aboveground location, MiniCHANDLER subverts both of these norms.

    The detector uses solid scintillator technology, which will allow it to record about 100 antineutrino interactions per day. This interaction rate is less than the rate at large detectors, but MiniCHANDLER makes up for this with its precise tracking of antineutrinos.

    Small plastic cubes pinpoint where in MiniCHANDLER an antineutrino interacts by detecting light from the interaction. However, the same kind of light signal can also come from other passing particles like cosmic rays. To distinguish between the antineutrino and the riffraff, Link and his colleagues look for multiple signals to confirm the presence of an antineutrino.

    Those signs come from a process called inverse beta decay. Inverse beta decay occurs when an antineutrino collides with a proton, producing light (the first event) and also kicking a neutron out of the nucleus of the atom. These emitted neutrons are slower than the light and are picked up as a secondary signal to confirm the antineutrino interaction.

    “[MiniCHANDLER] is going to sit on the surface; it’s not shielded well at all. So it’s going to have a lot of background,” Link says. “Inverse beta decay gives you a way of rejecting the background by identifying the two-part event.”

    Monitoring the reactors

    Scientists could find use for a mobile neutrino detector beyond studying reactor neutrinos. They could also use the detector to measure properties of the nuclear reactor itself.

    A mobile neutrino detector could be used to determine whether a reactor is in use, Oguri says. “Detection unambiguously means the reactors are in operation—nobody can cheat the status.”

    The detector could also be used to determine whether material from a reactor has been repurposed to produce nuclear weapons. Plutonium, an element used in the process of making weapons-grade nuclear material, produces 60 percent fewer detectable neutrinos than uranium, the primary component in a reactor core.

    “We could potentially tell whether or not the reactor core has the right amount of plutonium in it,” Link says.

    Using a neutrino detector would be a non-invasive way to track the material; other methods of testing nuclear reactors can be time-consuming and disruptive to the reactor’s processes.

    But for now, Link just wants MiniCHANDLER to achieve a simple—yet groundbreaking—goal: Get the mobile neutrino lab running.

    See the full article here .

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 3:45 pm on February 1, 2017 Permalink | Reply
    Tags: , Neutrinos, ,   

    From SA: “IceCube Closes in on Mysterious Nature of Neutrinos” 

    Scientific American

    Scientific American

    February 1, 2017
    Calla Cofield

    The Antarctica-based observatory has found hints of strange patterns in the ghostly particles’ masses

    1
    IceCube neutrino detector interior
    U Wisconsin IceCube Neutrino detector

    Buried under the Antarctic ice, the IceCube experiment was designed primarily to capture particles called neutrinos that are produced by powerful cosmic events, but it is also helping scientists learn about the fundamental nature of these ghostly particles.

    At a meeting of the American Physical Society (APS) in Washington, D.C., this week, scientists with the IceCube collaboration presented new results that contribute to an ongoing mystery about the nature of neutrinos. These particles pour down on Earth from the sun, but they mostly pass unimpeded, like ghosts, through regular matter.

    The new results support evidence of a strange symmetry in measurements of one neutrino mass. In particle physics, symmetries often indicate underlying physics that scientists haven’t yet unearthed. [Neutrinos from Beyond the Solar System Found (Images)]

    Mystery of the neutrino mass

    Neutrinos are fundamental particles of nature. They aren’t one of the particles that make up atoms. (Those are electrons, protons and neutrons.) Neutrinos very, very rarely interact with regular matter, so they don’t really influence human beings at all (unless, of course, you happen to be a particle physicist who studies them). The sun generates neutrinos in droves, but for the most part, those particles pour through the Earth, like phantoms.

    The [U Wisconsin] IceCube Neutrino Observatory is a neutrino detector buried under 0.9 miles (1.45 kilometers) of ice in Antarctica. The ice provides a shield from other types of radiation and particles that would otherwise overwhelm the rare instances when neutrinos do interact with the detector and create a signal for scientists to study.

    Neutrinos come in three “flavors”: the tau neutrino, the muon neutrino and the electron neutrino. For a long time, scientists debated whether neutrinos had mass or if they were similar to photons (particles of light), which are considered massless. Eventually, scientists showed that neutrinos do have mass, and the 2015 Nobel Prize was awarded for work on neutrinos, including investigations into neutrino masses.

    But saying that neutrinos have mass is not the same as saying that a rock or an apple has mass. Neutrinos are particles that exist in the quantum world, and the quantum world is weird—light can be both a wave and a particle; cats can be both alive and dead. So it’s not that each neutrino flavor has its own mass, but rather that the neutrino flavors combine into what are called “mass eigenstates,” and those are what scientists measure. (For the purpose of simplicity, a Michigan State University statement describing the new findings calls the mass eigenstates “neutrino species.”)

    “One of the outstanding questions is whether there is a pattern to the fractions that go into each neutrino species,” Tyce DeYoung, an associate professor of physics and astronomy at Michigan State University and one of the IceCube collaborators working on the new finding, told Space.com.

    One neutrino species appears to be made up of mostly electron neutrinos, with some muon and tau neutrinos; the second neutrino species seems to be an almost equal mix of all three; and the third is still a bit of a mystery, but one previous study suggested that it might be an even split between muon and tau, with just a few electron neutrinos thrown in.

    At the APS meeting, Joshua Hignight, a postdoctoral researcher at Michigan State University working with DeYoung, presented preliminary results from IceCube that support the equal split of muon and tau neutrinos in that third mass species.

    “This question of whether the third type is exactly equal parts muon and tau is called the maximal mixing question,” he said. “Since we don’t know any reason that this neutrino species should be exactly half and half, that would either be a really astonishing coincidence or possibly telling us about some physical principle that we haven’t discovered yet.”

    Generally speaking, any given feature of the universe can be explained either by a random process or by some rule that governs how things behave. If the number of muon and tau neutrinos in the third neutrino species were determined randomly, there would be much higher odds that those numbers would not be equal.

    “To me, this is very interesting, because it implies a fundamental symmetry,” DeYoung said.

    To better understand why the equal number of muon and tau neutrinos in the mass species implies nonrandomness, DeYoung gave the example of scientists discovering that protons and neutrons (the two particles that make up the nucleus of an atom) have very similar masses. The scientists who first discovered those masses might have wondered if that similarity was a mere coincidence or the product of some underlying similarity.

    It turns out, it’s the latter: Neutrons and protons are both made of three elementary particles called quarks (though a different combination of two quark varieties). In that case, a similarity on the surface indicated something hidden below, the scientists said.

    The new results from IceCube are “generally consistent” with recent results from the T2K neutrino experiment in Japan, which is dedicated to answering questions about the fundamental nature of neutrinos.

    T2K Experiment
    T2K map
    T2K Experiment

    But the Nova experiment, based at Fermi National Accelerator Laboratory [FNAL] outside Chicago, did not “prefer the exact symmetry” between the muon and tau neutrinos in the third mass species, according to DeYoung.

    FNAL/NOvA experiment
    FNAL/NOvA experiment map
    FNAL NOvA Near Detector
    FNAL NOvA Near Detector

    “That’s a tension; that’s not a direct contradiction at this point,” he said. “It’s the sort of not-quite-agreement that we’re going to be looking into over the next couple of years.”

    IceCube was designed to detect somewhat-high-energy neutrinos from distant cosmic sources, but most neutrino experiments on Earth detect lower-energy neutrinos from the sun or nuclear reactors on Earth. Both T2K and Nova detect neutrinos at about an order of magnitude lower energy than IceCube. The consistency between the measurements made by IceCube and T2K are a test of “the robustness of the measurement” and “a success for our standard theory” of neutrino physics, DeYoung said.

    Neutrinos don’t affect most people’s day-to-day lives, but physicists hope that by studying these particles, they can find clues about some of the biggest mysteries in the cosmos. One of those cosmic mysteries could include an explanation for dark matter, the mysterious stuff that is five times more common in the universe than the “regular” matter that makes up planets, stars and all of the visible objects in the cosmos. Dark matter has a gravitational pull on regular matter, and it has shaped the cosmic landscape throughout the history of the universe. Some theorists think dark matter could be a new type of neutrino.

    The IceCube results are still preliminary, according to DeYoung. The scientists plan to submit the final results for publication after they’ve finished running the complete statistical analysis of the data.

    See the full article here .

    Please help promote STEM in your local schools.

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    Scientific American, the oldest continuously published magazine in the U.S., has been bringing its readers unique insights about developments in science and technology for more than 160 years.

     
  • richardmitnick 1:58 pm on January 27, 2017 Permalink | Reply
    Tags: , Fermilab achieves milestone beam power for neutrino experiments, , , Main Injector, Neutrinos, , ,   

    From FNAL: “Fermilab achieves milestone beam power for neutrino experiments” 

    FNAL II photo

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

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

    January 26, 2017
    Ricarda Laasch

    1
    Thanks to recent upgrades to the Main Injector, Fermilab’s flagship accelerator, Fermilab scientists have produced 700-kilowatt proton beams for the lab’s experiments. Photo: Peter Ginter

    Fermilab’s accelerator is now delivering more neutrinos to experiments than ever before.

    The U.S. Department of Energy’s Fermi National Accelerator Laboratory has achieved a significant milestone for proton beam power. On Jan. 24, the laboratory’s flagship particle accelerator delivered a 700-kilowatt proton beam over one hour at an energy of 120 billion electronvolts.

    The Main Injector accelerator provides a massive number of protons to create particles called neutrinos, elusive particles that influence how our universe has evolved. Neutrinos are the second-most abundant matter particles in our universe. Trillions pass through us every second without leaving a trace.

    Because they are so abundant, neutrinos can influence all kinds of processes, such as the formation of galaxies or supernovae. Neutrinos might also be the key to uncovering why there is more matter than antimatter in our universe. They might be one of the most valuable players in the history of our universe, but they are hard to capture and this makes them difficult to study.

    “We push always for higher and higher beam powers at accelerators, and we are lucky our accelerator colleagues live for a challenge,” said Steve Brice, head of Fermilab’s Neutrino Division. “Every neutrino is an opportunity to study our universe further.”

    With more beam power, scientists can provide more neutrinos in a given amount of time. At Fermilab, that means more opportunities to study these subtle particles at the lab’s three major neutrino experiments: MicroBooNE, MINERvA and NOvA.

    FNAL/MicrobooNE
    FNAL/MicrobooNE

    FNAL/MINERvA
    FNAL/MINERvA

    FNAL/NOvA experiment
    FNAL/NOvA map

    FNAL NOvA Near Detector
    FNAL NOvA Near Detector

    “Neutrino experiments ask for the world, if they can get it. And they should,” said Dave Capista, accelerator scientist at Fermilab. Even higher beam powers will be needed for the future international Deep Underground Neutrino Experiment, to be hosted by Fermilab. DUNE, along with its supporting Long-Baseline Neutrino Facility, is the largest new project being undertaken in particle physics anywhere in the world since the Large Hadron Collider.

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

    “It’s a negotiation process: What is the highest beam power we can reasonably achieve while keeping the machine stable, and how much would that benefit the neutrino researcher compared to what they had before?” said Fermilab accelerator scientist Mary Convery.

    “This step-by-step journey was a technical challenge and also tested our understanding of the physics of high-intensity beams,” said Fermilab Chief Accelerator Officer Sergei Nagaitsev. “But by reaching this ambitious goal, we show how great the team of physicists, engineers, technicians and everyone else involved is.” The 700-kilowatt beam power was the goal declared for 2017 for Fermilab’s accelerator-based experimental program.

    Particle accelerators are complex machines with many different parts that change and influence the particle beam constantly. One challenge with high-intensity beams is that they are relatively large and hard to handle. Particles in accelerators travel in groups referred to as bunches.

    Roughly one hundred billion protons are in one bunch, and they need their space. The beam pipes – through which particles travel inside the accelerator – need to be big enough for the bunches to fit. Otherwise particles will scrape the inner surface of the pipes and get lost in the equipment.

    2
    The Main Injector, a 2-mile-circumference racetrack for protons, is the most powerful particle accelerator in operation at Fermilab. It provides proton beams for various particle physics experiments as well as Fermilab Test Beam Facility. Photo: Reidar Hahn

    Such losses, as they’re called, need to be controlled, so while working on creating the conditions to generate a high-power beam, scientists also study where particles get lost and how it happens. They perform a number of engineering feats that allow them to catch the wandering particles before they damage something important in the accelerator tunnel.

    To generate high-power beams, the scientists and engineers at Fermilab use two accelerators in parallel. The Main Injector is the driver: It accelerates protons and subsequently smashes them into a target to create neutrinos. Even before the protons enter the Main Injector, they are prepared in the Recycler.

    The Fermilab accelerator complex can’t create big bunches from the get-go, so scientists create the big bunches by merging two smaller bunches in the Recycler. A small bunch of protons is sent into the Recycler, where it waits until the next small bunch is sent in to join it. Imagine a small herd of cattle, and then acquiring a new herd of the same size. Rather than caring for them separately, you allow the two herds to join each other on the big meadow to form a big herd. Now you can handle them as one herd instead of two.

    In this way Fermilab scientists double the number of particles in one bunch. The big bunches then go into the Main Injector for acceleration. This technique to increase the number of protons in each bunch had been used before in the Main Injector, but now the Recycler has been upgraded to be able to handle the process as well.

    “The real bonus is having two machines doing the job,” said Ioanis Kourbanis, who led the upgrade effort. “Before we had the Recycler merging the bunches, the Main Injector handled the merging process, and this was time consuming. Now, we can accelerate the already merged bunches in the Main Injector and meanwhile prepare the next group in the Recycler. This is the key to higher beam powers and more neutrinos.”

    Fermilab scientists and engineers were able to marry two advantages of the proton acceleration technique to generate the desired truckloads of neutrinos: increase the numbers of protons in each bunch and decrease the delivery time of those proton to create neutrinos.

    “Attaining this promised power is an achievement of the whole laboratory,” Nagaitsev said. “It is shared with all who have supported this journey.”

    The new heights will open many doors for the experiments, but no one will rest long on their laurels. The journey for high beam power continues, and new plans for even more beam power are already under way.

    See the full article here .

    Please help promote STEM in your local schools.

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    FNAL Icon
    Fermilab Campus

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

     
  • richardmitnick 11:50 am on January 19, 2017 Permalink | Reply
    Tags: , , Neutrinos,   

    From SURF: “Ventilation critical to DUNE success” 

    SURF logo
    Sanford Underground levels

    Sanford Underground Research facility

    January 17, 2017
    Constance Walter

    1
    Above: The Oro Hondo shaft exhaust fan is essential to controling airflow underground. Below [?]: A laser scanner was lowered into the shaft to map its integrety. Credit: Matthew Kapust

    Air flows down the Yates and Ross shafts and is pulled through specific areas underground by two air shafts: Number 5 Shaft and the Oro Hondo. With the Deep Underground Neutrino Experiment (DUNE) just on the horizon, the reliability of the Oro Hondo ventilation system, in particular, is critical.

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

    A direct drive, variable-frequency fan powered by a 3000 horsepower synchronous motor (it currently draws less than 400 hp), the Oro Hondo was built in 1986. Since then, it has undergone repairs and had parts replaced as needed and, in 2010, underwent a significant rebuild as Sanford Lab prepared to install the first physics experiments on the 4850 Level.

    Deterioration of the shaft can inhibit airflow, so it was critical to understand the integrity of the wall rock, said Bryce Pietzyk, underground access director. However, because there is no conveyance in the shaft, Pietzyk turned to experts to find a way to get “eyes on” the rock from the surface to the current muck pile elevation. A special scanning method, developed by Professional Mapping Services, Firmatek and Mine Vision Systems, was lowered into the shaft to collect data on ground conditions.

    “We learned a lot from the baseline scan, and things look good right now,” Pietzyk said. “But we’ll need to do more scans over time to really understand locations of zones where rock wall conditions have deteriorated.” Additional scans will help create a more complete picture of the conditions of the shaft.

    Ventilation surveys helped Sanford Lab engineers determine that while the fan was operating well, the drive system is obsolete and unreliable, and the motor and bearings require preventive maintenance before Long-Baseline Neutrino Facilty (LBNF) starts major construction. Tests also revealed minor corrosion in the ducting, which will be sandblasted and coated to slow further corrosion.

    “But, overall, the entire system is much more efficient than we anticipated,” said Allan Stratman, engineering director.

    Finally, to improve air flow, a borehole needs to be raised from the 4850 to the 3650 Level and improvements made to 31 exhaust, an existing ventilation path. It’s all part of the plans for the LBNF, which will power DUNE.

    Scientists working on DUNE hope to answer questions about the role neutrinos play in the universe, learn more about the formation of neutron stars and black holes and, quite possibly, figure out just how much mass these elusive particles have.

    A neutrino beam will be sent from Fermilab [FNAL] near Chicago, Ill., 800 miles through the earth to Sanford Lab in Lead, S.D. Although no tunnel is required for the neutrino beam, huge caverns must be excavated to house four massive liquid argon detectors on the 4850 Level of Sanford Lab.

    FNAL DUNE Argon tank at SURF
    FNAL DUNE Argon tank at SURF

    Nearly 800,000 tons of rock will be excavated. Proper ventilation is critical when doing construction underground. And that’s why the Oro Hondo is so important to the success of DUNE.

    “This is the only shaft that can provide enough ventilation for the amount of excavation LBNF requires and to remove heat from the DUNE caverns during operations,” said Joshua Willhite, deputy project manager for the LBNF Far Site (Sanford Lab) Conventional Facilities. “The fan has to be highly reliable to reduce risk.”

    See 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 3:45 pm on January 16, 2017 Permalink | Reply
    Tags: , , Neutrinos, ,   

    From SURF: “Neutrinos: Spies of the sun” 

    SURF logo
    Sanford Underground levels

    Sanford Underground Research facility

    November 21, 2016 [Just caught up with this.]
    Constance Walter

    1
    Hydrogen plasma glows at the ion source of the LUNA accelerator. The plasma is needed to extract and accelerate protons. Credit: LUNA experiment

    As a young man, Frank Strieder was fascinated with astrophysics, reading every book he could find and taking high-level courses in math and physics while in high school in Germany. One day in particular stands out.

    “My teacher said, ‘Ah, but neutrinos have never been measured from the sun.’ I said, ‘No, no, no. There’s an experiment by Ray Davis somewhere in the United States at an underground gold mine.’ And the teacher said, ‘No, that is not the case,’” said Strieder, a professor of physics at the South Dakota School of Mines and Technology (SD Mines).

    “Now, almost 30 years later, I’m at that same place doing my own experiment in the same environment,” said Strieder, who is also the principal investigator for CASPAR (Compact Accelerator System for Performing Astrophysical Research) at Sanford Lab.

    For nearly three decades, Davis counted solar neutrinos on the 4850 Level of the former Homestake Mine. But there was a problem. Davis consistently counted only one-third the number of neutrinos predicted by theorists, creating what came to be called the “solar neutrino problem.”

    Initially, the scientific community thought the experiment must be wrong, but Davis insisted he was right. He was vindicated when two underground experiments in Canada and Japan showed that neutrinos oscillate, or change among three types, as they travel through space at nearly the speed of light. In 2002, Davis earned a share of the Nobel Prize in Physics.

    But even before the Nobel, Davis’s work inspired experiments around the world, including the Laboratory for Underground Nuclear Astrophysics (LUNA) at Gran Sasso National Laboratory in Italy.

    Gran Sasso LABORATORI NAZIONALI del GRAN SASSO
    Gran Sasso LABORATORI NAZIONALI del GRAN SASSO

    The first underground accelerator for astrophysics, LUNA has been looking at stellar nuclear burning in the sun for 25 years.

    “Ray Davis used neutrinos as spies of the sun, to try to prove what was happening in the sun,” said Matthias Junker, a scientist with the LUNA collaboration. “As we have fixed our idea of what is a neutrino, we can use it to probe what is going on inside the sun.”

    Strieder worked with Junker on the LUNA experiment for 22 years before moving to CASPAR two years ago.

    CASPAR's accelerator is expected to be operational by 2015
    CASPAR’s accelerator is expected to be operational by 2015

    Although both experiments are studying stellar burning and evolutionary phases in stars, their work is different. CASPAR is interested in understanding the production of elements heavier than iron, while LUNA concentrates on the production of elements up to magnesium, aluminum and others in that area.

    “This nuclear burning produces all the isotopes that make up life,” Junker said. “Where does carbon come from? Oxygen? Nitrogen? Lead? Gold? It’s all produced within stars. If you have a better understanding of the stars, you can use them to probe the universe.”

    LUNA and CASPAR are the only experiments doing this type of research, Junker said. “Of course, there is competition but there is also sharing knowledge and experience.”

    And it all started with neutrinos and the pioneering work done by Ray Davis.

    On a recent visit to Sanford Lab, Junker said, “For me, this moment is extremely thrilling. This is the root of neutrino research.”

    See 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 11:31 am on January 11, 2017 Permalink | Reply
    Tags: , How heavy is a neutrino?, Neutrinos, ,   

    From Symmetry: “How heavy is a neutrino?” 

    Symmetry Mag

    Symmetry

    01/10/17
    Kathryn Jepsen

    1
    No image caption. No image credit.

    The question is more complicated than it seems.

    Neutrinos are elementary particles first discovered six decades ago.

    Over the years, scientists have learned several surprising things about them. But they have yet to answer what might sound like a basic question: How much do neutrinos weigh? The answer could be key to understanding the nature of the strange particles and of our universe.

    To understand why figuring out the mass of neutrinos is such a challenge, first you must understand that there’s more than one way to picture a neutrino.

    Neutrinos come in three flavors: electron, muon and tau. When a neutrino hits a neutrino detector, a muon, electron or tau particle is produced. When you catch a neutrino accompanied by an electron, you call it an electron neutrino, and so on.

    Knowing this, you might be forgiven for thinking that there are three types of neutrinos: electron neutrinos, muon neutrinos and tau neutrinos. But that’s not quite right.

    That’s because every neutrino is actually a quantum superposition of all three flavors. Depending on the energy of a neutrino and where you catch it on its journey, it has a different likelihood of appearing as electron-flavored, muon-flavored or tau-flavored.

    Armed with this additional insight, you might be forgiven for thinking that, when all is said and done, there is actually just one type of neutrino. But that’s even less right.

    Scientists count three types of neutrino after all. Each one has a different mass and is a different mixture of the three neutrino flavors. These neutrino types are called the three neutrino mass states.

    2
    Sandbox Studio, Chicago with Corinne Mucha

    A weighty problem

    We know that the masses of these three types of neutrinos are small. We know that the flavor mixture of the first neutrino mass state is heavy on electron flavor. We know that the second is more of an even blend of electron, muon and tau. And we know that the third is mostly muon and tau.

    We know that the masses of the first two neutrinos are close together and that the third is the odd one out. What we don’t know is whether the third one is lighter or heavier than the others.

    The question of whether this third mass state is the heaviest or the lightest mass state is called the neutrino mass hierarchy (or neutrino mass ordering) problem.

    3
    No image caption. No image credit.

    Easy as 1,2,3—or 3,1,2?

    Some models that unify the different forces in the Standard Model of particle physics predict that the neutrino mass ordering will follow the pattern 1, 2, 3—what they call a normal hierarchy. Other models predict that the mass ordering will follow the pattern 3, 1, 2—an inverted hierarchy. Knowing whether the hierarchy is normal or inverted can help theorists answer other questions.

    For example, four forces—the strong, weak, electromagnetic and gravitational forces—govern the interactions of the smallest building blocks of matter. Some theorists think that, in the early universe, these four forces were united into a single force. Most theories about the unification of forces predict a normal neutrino mass hierarchy.

    Scientists’ current best tools for figuring out the neutrino mass hierarchy are long-baseline neutrino experiments, most notably one called NOvA.

    FNAL/NOvA experiment
    NOvA map
    FNAL NOvA Near Detector
    FNAL NOvA Near Detector

    3
    No image caption. No image credit.

    Electron drag

    The NOvA detector, located in Minnesota near the border of Canada, studies a beam of neutrinos that originates at Fermi National Accelerator Laboratory in Illinois.

    Neutrinos very rarely interact with other matter. That means they can travel 500 miles straight through the Earth from the source to the detector. In fact, it’s important that they do so, because as they travel, they pass through trillions of electrons.

    This affects the electron-flavor neutrinos—and only the electron-flavor neutrinos—making them seem more massive. Since the first and second mass states contain more electron flavor than the third, those two experience the strongest electron interactions as they move through the Earth.

    This interaction has different effects on neutrinos and antineutrinos—and the effects depend on the mass hierarchy. If the hierarchy is normal, muon neutrinos will be more likely to turn into electron neutrinos, and muon antineutrinos will be less likely to turn into electron antineutrinos. If the hierarchy is inverted, the opposite will happen.

    So if NOvA scientists see that, after traveling through miles of rock and dirt, more muon neutrinos and fewer muon antineutrinos than expected have shifted flavors, it will be a sign the mass hierarchy is normal. If they see fewer muon neutrinos and more muon antineutrinos have shifted flavors, it will be a sign that the mass hierarchy is inverted.

    The change is subtle. It will take years of data collection to get the first hint of an answer. Another, shorter long-baseline neutrino experiment, T2K, is taking related measurements. The JUNO experiment under construction in China aims to measure the mass hierarchy in a different way. The definitive measurement likely won’t come until the next generation of long-baseline experiments, DUNE in the US and the proposed Hyper-Kamiokande experiment in Japan.

    T2K Experiment
    T2K map
    T2K, Japan

    JUNO Neutrino detector China
    JUNO Neutrino detector, at Kaiping, Jiangmen in Southern China

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

    Hyper-Kamiokande, a neutrino physics laboratory located underground in the Mozumi Mine of the Kamioka Mining and Smelting Co. near the Kamioka section of the city of Hida in Gifu Prefecture, Japan.
    Hyper-Kamiokande, a neutrino physics laboratory located underground in the Mozumi Mine of the Kamioka Mining and Smelting Co. near the Kamioka section of the city of Hida in Gifu Prefecture, Japan

    Neutrinos are some of the most abundant particles in the universe. As we slowly uncover their secrets, they give us more clues about how our universe works.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

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    Symmetry is a joint Fermilab/SLAC publication.


     
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