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  • richardmitnick 8:23 pm on May 24, 2016 Permalink | Reply
    Tags: , , , Neutrinos, SURF   

    From SURF: “DUNE building prototype cryostats” 

    SURF logo
    Sanford Underground levels

    Sanford Underground Research facility

    May 24, 2016
    Connie Walker

    SURF DUNE Cryostats

    In the next frontier of particle physics, scientists with the Long-Baseline Neutrino Facility and associated Deep Underground Neutrino Experiment (LBNF/DUNE) hope to make discoveries about neutrinos that could answer fundamental questions about the origins of the universe, learn more about the properties of neutrinos and do further studies in proton decay. They will do this by sending a beam of neutrinos 800 miles through the Earth from Fermi National Accelerator Lab [FNAL] in Batavia, Ill., to underground detectors at the Sanford Underground Research Facility in Lead, S.D.

    But before they can begin that work, they need to be sure the detectors and cryogenic systems will work the way they need them to. That’s where engineer David Montanari comes in.

    Montanari, the cryogenics infrastructure project manager for the LBNF Far Site Facilities and the U.S. liaison at CERN for LBNF, oversees the design of the cryogenic systems that will cool and
    purify the detectors. It’s a big experiment—DUNE will be 100 times bigger than any liquid-argon particle detectors that have come before—that requires big prototypes.

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

    FNAL LBNF/DUNE
    FNAL LBNF/DUNE

    “Large cryogenis systems are not a mystery. They have been done before and they exist in the industry,” Montanari said. For example, he said, the gas industry uses large tanks to store and cool natural gas and move the liquefied version around the world. “There are large air separation plants where they’ve produced liquid argon and liquid nitrogen—the liquid gases that we use in our
    experiments—and they can make it pure. The point is always that we want to make it super pure; that is what separates us from industry.”

    DUNE scientists chose liquid argon for its ability to detect the different types of neutrinos. To keep it in a liquid state, it must be cooled to minus 300 degrees Fahrenheit (minus 184 degrees Celsius or 88 degrees Kelvin).

    The large DUNE prototypes being designed now are not be the first. Scientists built and tested a small, 35-ton at Fermilab.

    “This proves that that we can make a cryostat and we can put a detector inside and we can achieve the purity we need,” Montanari said. “Now, we want to do it bigger and and make sure the bigger
    one is pure as well.”

    The new prototypes will consist of a dual-phase detector that will contain argon in both its liquid and gaseous forms, and a single-phase detector that will need liquid argon only. Although the cryostats will be identical dimensionwise, they will have independent cryogenic systems designed to accommodate the needs of each.

    “This is important because we want to optimize the design and construction,” Montanari said. “So, by the time we go to LBNF/DUNE, we know how to make it and how to make it faster and better.”

    In a presentation at the recent DUNE Collaboration meeting, co-spokesperson Mark Thomson, professor of physics at the Universityof Cambridge, said the goal is to have the prototypes completed by the fall of 2018. “In comparison,” he said, “the Empire State Building was built in 400 days.”

    It’s an aggressive timeline, but one with a purpose, Montanari said. The prototypes will be built at CERN and the Collaboration plans to use a particle beam producedby a particle accelerator to
    test the prototypes. “The timing is essential because the DUNE collaboration wants to take physics data with the beam as long as there is a beam.”

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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 6:32 am on May 13, 2016 Permalink | Reply
    Tags: , , , Neutrinos   

    From NASA Fermi: “NASA’s Fermi Telescope Helps Link Cosmic Neutrino to Blazar Blast” 

    NASA Fermi Banner

    NASA/Fermi Telescope
    Fermi

    April 28, 2016
    By Francis Reddy
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    Nearly 10 billion years ago, the black hole at the center of a galaxy known as PKS B1424-418 produced a powerful outburst. Light from this blast began arriving at Earth in 2012. Now astronomers using data from NASA’s Fermi Gamma-ray Space Telescope and other space- and ground-based observatories have shown that a record-breaking neutrino seen around the same time likely was born in the same event.


    Access mp4 video here.
    NASA Goddard scientist Roopesh Ojha explains how Fermi and TANAMI uncovered the first plausible link between a blazar eruption and a neutrino from deep space. Credits: NASA’s Goddard Space Flight Center

    “Neutrinos are the fastest, lightest, most unsociable and least understood fundamental particles, and we are just now capable of detecting high-energy ones arriving from beyond our galaxy,” said Roopesh Ojha, a Fermi team member at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and a coauthor of the study. “Our work provides the first plausible association between a single extragalactic object and one of these cosmic neutrinos.”

    Although neutrinos far outnumber all the atoms in the universe, they rarely interact with matter, which makes detecting them quite a challenge. But this same property lets neutrinos make a fast exit from places where light cannot easily escape — such as the core of a collapsing star — and zip across the universe almost completely unimpeded. Neutrinos can provide information about processes and environments that simply aren’t available through a study of light alone.

    The IceCube Neutrino Observatory, built into a cubic kilometer of clear glacial ice at the South Pole, detects neutrinos when they interact with atoms in the ice.

    U Wisconsin ICECUBE neutrino detector
    IceCube neutrino detector interior
    U Wisconsin ICECUBE neutrino detector

    This triggers a cascade of fast-moving charged particles that emit a faint glow, called Cerenkov light, as they travel, which is picked up by thousands of optical sensors strung throughout IceCube. Scientists determine the energy of an incoming neutrino by the amount of light its particle cascade emits.

    To date, the IceCube science team has detected about a hundred very high-energy neutrinos and nicknamed some of the most extreme events after characters on the children’s TV series “Sesame Street.” On Dec. 4, 2012, IceCube detected an event known as Big Bird, a neutrino with an energy exceeding 2 quadrillion electron volts (PeV). To put that in perspective, it’s more than a million million times greater than the energy of a dental X-ray packed into a single particle thought to possess less than a millionth the mass of an electron. Big Bird was the highest-energy neutrino ever detected at the time and still ranks second.

    Where did it come from? The best IceCube position only narrowed the source to a patch of the southern sky about 32 degrees across, equivalent to the apparent size of 64 full moons.

    Enter Fermi. Starting in the summer of 2012, the satellite’s Large Area Telescope (LAT) witnessed a dramatic brightening of PKS B1424-418, an active galaxy classified as a gamma-ray blazar.

    NASA/Fermi LAT
    NASA/Fermi LAT

    An active galaxy is an otherwise typical galaxy with a compact and unusually bright core. The excess luminosity of the central region is produced by matter falling toward a supermassive black hole weighing millions of times the mass of our sun. As it approaches the black hole, some of the material becomes channeled into particle jets moving outward in opposite directions at nearly the speed of light. In blazars, one of these jets happens to point almost directly toward Earth.

    l
    Left
    r
    Right

    Fermi LAT images showing the gamma-ray sky around the blazar PKS B1424-418. Brighter colors indicate greater numbers of gamma rays. The dashed arc marks part of the source region established by IceCube for the Big Bird neutrino (50-percent confidence level). Left: An average of LAT data centered on July 8, 2011, and covering 300 days when the blazar was inactive. Right: An average of 300 active days centered on Feb. 27, 2013, when PKS B1424-418 was the brightest blazar in this part of the sky. Credits: NASA/DOE/LAT Collaboration

    During the year-long outburst, PKS B1424-418 shone between 15 and 30 times brighter in gamma rays than its average before the eruption. The blazar is located within the Big Bird source region, but then so are many other active galaxies detected by Fermi.

    The scientists searching for the neutrino source then turned to data from a long-term observing program named TANAMI. Since 2007, TANAMI has routinely monitored nearly 100 active galaxies in the southern sky, including many flaring sources detected by Fermi. The program includes regular radio observations using the Australian Long Baseline Array (LBA) and associated telescopes in Chile, South Africa, New Zealand and Antarctica. When networked together, they operate as a single radio telescope more than 6,000 miles across and provide a unique high-resolution look into the jets of active galaxies.

    Australian Long Baseline Array
    Australian Long Baseline Array map

    ATNF TANAMI array Australia
    ATNF TANAMI array Australia

    3
    Radio images from the TANAMI project reveal the 2012-2013 eruption of PKS B1424-418 at a wavelength of 8.4 GHz. The core of the blazar’s jet brightened by four times, producing the most dramatic blazar outburst TANAMI has observed to date. Credits: TANAMI

    Three radio observations of PKS B1424-418 between 2011 and 2013 cover the period of the Fermi outburst. They reveal that the core of the galaxy’s jet had brightened by about four times. No other galaxy observed by TANAMI over the life of the program has exhibited such a dramatic change.

    “We combed through the field where Big Bird must have originated looking for astrophysical objects capable of producing high-energy particles and light,” said coauthor Felicia Krauss, a doctoral student at the University of Erlangen-Nuremberg in Germany. “There was a moment of wonder and awe when we realized that the most dramatic outburst we had ever seen in a blazar happened in just the right place at just the right time.”

    In a paper* published Monday, April 18, in Nature Physics, the team suggests the PKS B1424-418 outburst and Big Bird are linked, calculating only a 5-percent probability the two events occurred by chance alone. Using data from Fermi, NASA’s Swift and WISE satellites, the LBA and other facilities, the researchers determined how the energy of the eruption was distributed across the electromagnetic spectrum and showed that it was sufficiently powerful to produce a neutrino at PeV energies.

    NASA/SWIFT Telescope
    NASA/SWIFT Telescope

    NASA/Wise Telescope
    NASA/Wise Telescope

    “Taking into account all of the observations, the blazar seems to have had means, motive and opportunity to fire off the Big Bird neutrino, which makes it our prime suspect,” said lead author Matthias Kadler, a professor of astrophysics at the University of Wuerzburg in Germany.

    Francis Halzen, the principal investigator of IceCube at the University of Wisconsin–Madison, and not involved in this study, thinks the result is an exciting hint of things to come. “IceCube is about to send out real-time alerts when it records a neutrino that can be localized to an area a little more than half a degree across, or slightly larger than the apparent size of a full moon,” he said. “We’re slowly opening a neutrino window onto the cosmos.”

    For more information about NASA’s Fermi, visit:

    http://www.nasa.gov/fermi

    *Science paper:
    Coincidence of a high-fluence blazar outburst with a PeV-energy neutrino event

    See the full article here .

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    NASA’s Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy and with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States.

     
  • richardmitnick 11:40 am on May 10, 2016 Permalink | Reply
    Tags: , Neutrinos, Precision Oscillation and Spectrum Experiment (PROSPECT),   

    From Yale University: “The Missing Link in Particle Physics” 

    Yale University bloc

    Yale University

    March 31, 2016 [sorry, I missed this because unknown to me, after you “like” a Facebook page, you still need to turn notifications on.
    For some strange reason, the default is to have them off. I mean, you know, why take the page if you are not interested
    in its content? Slowly, one by one I am getting them turned on as I come up against problems like this. But, in the
    end, we get the story. Even with the notifications turned off, this one just popped up.]

    Mary Chukwu

    1

    Dark matter? Particle accelerators? Higgs boson? Particle physics has left the public fascinated, and perhaps puzzled, by its potential implications. Current work on an obscure particle called the neutrino may leave even physicists grasping for answers. Researchers at the Yale Wright Laboratory led by professor Karsten Heeger currently design and implement experiments to investigate if neutrinos are a new form of matter. Such a discovery would require a major revision of the Standard Model of Particle Physics.

    Standard ModelThe Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.
    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth

    According to the Standard Model of Particle Physics, neutrinos are neutral, massless elementary particles—matter that cannot be further subdivided. The neutrino can take three forms, the electron, tau, or muon neutrinos, and can only be acted upon by the universal weak force. The Standard Model attempts to explain the interactions in the subatomic world but cannot account for phenomena such as dark matter and dark energy.

    The Wright Lab’s research on neutrinos is groundbreaking because it shows that the assumptions of the Standard Model are even more flawed than previously thought. In 2016, Heeger shared the Breakthrough Prize in Fundamental Physics for three experiments showing that neutrinos can change their “flavor” as they travel through space. These changes in flavor—from electron to muon neutrinos, for example—are called neutrino oscillations and show that neutrinos have mass.

    “If you weighed all neutrinos in the universe, their combined mass would equal that of the mass of all the visible stars in the sky,” Heeger explained.

    Heeger’s group is involved in several neutrino experiments to determine the nature and mass of the neutrino and to search for the existence of a possible fourth form of neutrino—the sterile neutrino. One of these, Project 8, makes inferences about neutrinos based on electrons emitted from radioactive beta decay.

    U Washington Project 8 Full setup
    U Washington Project 8 Full setup

    Another project called the Cryogenic Underground Observatory for Rare Events (CUORE) studies a special form of nuclear decay called neutrino-less double beta decay and tests if neutrinos are their own antiparticles.

    CUORE experiment UC Berkeley
    CUORE experiment UC Berkeley

    Every particle has a counterpart antiparticle with the same mass but opposite charge; in the chargeless neutrino’s case, a quantum mechanical property called handedness varies instead. Antineutrinos are directly detected from nuclear reactors and indicate the presence of neutrinos. In ordinary double beta decay, two neutrons within a nucleus change into two protons and emit two electrons and two antineutrinos. However, in neutrino-less double beta decay, two neutrons are converted into two protons and two electrons are emitted—no antineutrinos. This is possible only if neutrinos are their own antiparticle.

    The Precision Oscillation and Spectrum Experiment (PROSPECT) investigates neutrinos taken from an active nuclear reactor.

    Yale PROSPECT Neutrino experiment
    Yale PROSPECT Neutrino experiment

    What distinguishes this project is its short baseline, or distance between the neutrino source and detector—10 meters rather than the usual hundreds. The experiment measures the variation in neutrino flavor—the neutrino oscillation—over short distances. Results could provide evidence for the sterile neutrino, which is unaffected by the weak force and thus an entirely new form of matter.

    The discovery of the sterile neutrino would be no less than a “paradigm-shift for the whole [scientific] community,” said Danielle Norcini, a graduate student working on PROSPECT.

    Findings about whether neutrinos are their own antiparticles and whether sterile neutrinos exist could require a revision of the long-standing Standard Model of Particle Physics.

    “If neutrinos are their own antiparticles, then there has to be a new term in the [Standard Model] that describes how particles get their mass…there has to be more than just the Higgs boson. If we discover sterile neutrinos, then there would have to be a whole new class of matter [added to the theory],” Heeger said.

    Aside from its implications in theoretical physics, neutrino research has tangible applications. Beyond the laboratories of experimental physics, advanced forms of neutrino detection would prove valuable to nuclear reactor monitoring. Neutrinos from a reactor core can describe the contents of the reactor, including the type of radioactive fuel used and the type of radioactive decay occurring. Some of the unique advantages of neutrino detection include its harmlessness, as neutrinos do not affect humans physically, as well as the neutrinos’ ability to pass through any barrier unimpeded—no man-made method can hide their presence.

    In addition, neutrinos are integral to the grand scheme of the universe as we know it.

    “Without neutrinos, supernovae wouldn’t happen. Supernovae are important for producing the elements that we are made of,” Heeger said.

    Future Wright Lab research will further the scientific understanding of neutrinos and particle physics with applications that extend into cosmology and astrophysics.

    3

    See the full article here .

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    Yale University Campus

    Yale University comprises three major academic components: Yale College (the undergraduate program), the Graduate School of Arts and Sciences, and the professional schools. In addition, Yale encompasses a wide array of centers and programs, libraries, museums, and administrative support offices. Approximately 11,250 students attend Yale.

     
  • richardmitnick 1:52 pm on May 3, 2016 Permalink | Reply
    Tags: , , Neutrinos   

    From FNAL: “Preparing for the sterile neutrino search: Fermilab breaks ground on Short-Baseline Near Detector building” 

    FNAL II photo

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

    May 3, 2016
    Rashmi Shivni

    1
    Fermilab broke ground on the Short-Baseline Neutrino Detector building on April 27. From left: Josh Kenney, FESS; Steve Dixon, AD; David Schmitz, University of Chicago; Ting Miao, ND; Ornella Palamara, ND; Peter Wilson, ND; Catherine James, ND. Photo: Reidar Hahn

    FNAL Short-Baseline Near Detector
    FNAL Short-Baseline Near Detector

    On April 27, Fermilab broke ground on the building that will house the future Short-Baseline Near Detector.

    The particle detector, SBND, is one of three that, together, scientists will use to search for the sterile neutrino, a hypothesized particle whose existence, if confirmed, could not only help us better understand the types of neutrino we already know about, but also provide clues about how the universe formed.

    Members of the Fermilab Neutrino and Particle Physics divisions, working together with international collaborators, are currently refining the design of the detector itself. It will take about eight months to complete the SBND building.

    The three detectors make up the laboratory’s Short-Baseline Neutrino Program, which will use a powerful neutrino beam generated by the Fermilab accelerator complex. The beam will pass first through SBND and then through the MicroBooNE detector, which is already installed and taking data, having observed its first neutrino interactions in October. Finally, the beam will travel through ICARUS, the largest of the three detectors. ICARUS, which was used in a previous experiment at the Italian Gran Sasso laboratory, is currently at the CERN laboratory in Switzerland receiving upgrades before its big move to Fermilab in 2017.

    FNAL/Microboone
    FNAL/MicrobooNE

    FNAL/ICARUS
    FNAL/ICARUS

    INFN Gran Sasso ICARUS
    INFN Gran Sasso ICARUS, previous home of ICARUS

    “The entire Short-Baseline Neutrino Program is looking for oscillations, or the transformations, of muon neutrinos into electron neutrinos,” said Peter Wilson, SBN program coordinator. “Sterile neutrinos might have a role in this oscillation process.”

    The beam coming out of the accelerator comprises primarily muon neutrinos; the detectors will measure their transformation into electron neutrinos.

    All three detectors have specific functions in detecting the transformation. As the detector closest to the beam source, SBND will take an initial measurement of the beam’s composition – how much the beam contains each of the different neutrino types.

    “The intermediary and far detectors are used to search for sterile neutrinos in two different ways,” said Ornella Palamara, co-spokesperson for the SBND experiment. “Either there’s an appearance of an excess of electron neutrinos or there’s a disappearance of the number of muon neutrinos compared to the number we start with.”

    If there are more electron neutrinos than predicted, then muon neutrinos may have oscillated first into sterile neutrinos and then to electron neutrinos. If the data show a smaller number of muon neutrinos than predicted, the muon neutrinos may have transformed only into sterile neutrinos, which cannot be seen in the far detectors.

    Scientists first picked up on experimental hints of a sterile neutrino at Los Alamos National Laboratory’s LSND experiment in 1995. When the Fermilab experiment MiniBooNE followed up, scientists could not confirm the sterile neutrino’s existence, but neither could they rule it out.

    “That’s the power of this program,” Palamara said. “We’re building off previous measurements, but we have more sensitive tools to measure the neutrinos.”

    Part of the sensitivity of SBND lies in its liquid-argon time projection chamber, the active part of the detector, which will contain 112 tons of liquid argon. Neutrinos will interact with the nuclei of the argon atoms, and scientists on SBND will study the resulting particles to better understand the neutrinos that caused the interaction. Their findings will likely have application in future accelerator-based neutrino programs, such as the international Deep Underground Neutrino Experiment hosted by Fermilab.

    The Short-Baseline Neutrino Program will begin taking data in 2018.

    “The SBND groundbreaking is a noteworthy milestone, but it’s part of a much larger program,” Wilson said. “Many people are working on it, and everyone is excited to get the chance to understand new physics.”

    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 1:40 pm on May 3, 2016 Permalink | Reply
    Tags: , , EXO-200 experiment, Neutrinos,   

    From Symmetry: “EXO-200 resumes its underground quest” 

    Symmetry Mag
    Symmetry

    05/03/16
    Matthew R. Francis

    EXO-200 Enriched Xenon Observatory near Carlsbad, New Mexico
    SLAC EXO-200 Enriched Xenon Observatory near Carlsbad, New Mexico

    The upgraded experiment aims to discover if neutrinos are their own antiparticles.

    Science is often about serendipity: being open to new results, looking for the unexpected.

    The dark side of serendipity is sheer bad luck, which is what put the Enriched Xenon Observatory experiment, or EXO-200, on hiatus for almost two years.

    Accidents at the Department of Energy’s underground Waste Isolation Pilot Project (WIPP) facility near Carlsbad, New Mexico, kept researchers from continuing their search for signs of neutrinos and their antimatter pairs. Designed as storage for nuclear waste, the site had both a fire and a release of radiation in early 2014 in a distant part of the facility from where the experiment is housed. No one at the site was injured. Nonetheless, the accidents, and the subsequent efforts of repair and remediation, resulted in a nearly two-year suspension of the EXO-200 effort.

    Things are looking up now, though: Repairs to the affected area of the site are complete, new safety measures are in place, and scientists are back at work in their separate area of the site, where the experiment is once again collecting data. That’s good news, since EXO-200 is one of a handful of projects looking to answer a fundamental question in particle physics: Are neutrinos and antineutrinos the same thing?

    The neutrino that wasn’t there

    Each type of particle has its own nemesis: its antimatter partner. Electrons have positrons—which have the same mass but opposite electric charge—quarks have antiquarks and protons have antiprotons. When a particle meets its antimatter version, the result is often mutual annihilation. Neutrinos may also have antimatter counterparts, known as antineutrinos. However, unlike electrons and quarks, neutrinos are electrically neutral, so antineutrinos look a lot like neutrinos in many circumstances.

    In fact, one hypothesis is that they are one and the same. To test this, EXO-200 uses 110 kilograms of liquid xenon (of its 200kg total) as both a particle source and particle detector. The experiment hinges on a process called double beta decay, in which an isotope of xenon has two simultaneous decays, spitting out two electrons and two antineutrinos. (“Beta particle” is a nuclear physics term for electrons and positrons.)

    If neutrinos and antineutrinos are the same thing, sometimes the result will be neutrinoless double beta decay. In that case, the antineutrino from one decay is absorbed by the second decay, canceling out what would normally be another antineutrino emission. The challenge is to determine if neutrinos are there or not, without being able to detect them directly.

    “Neutrinoless double beta decay is kind of a nuclear physics trick to answer a particle physics problem,” says Michelle Dolinski, one of the spokespeople for EXO-200 and a physicist at Drexel University. It’s not an easy experiment to do.

    EXO-200 and similar experiments look for indirect signs of neutrinoless double beta decay. Most of the xenon atoms in EXO-200 are a special isotope containing 82 neutrons, four more than the most common version found in nature. The isotope decays by emitting two electrons, changing the atom from xenon into barium. Detectors in the EXO-200 experiment collect the electrons and measure the light produced when the beta particles are stopped in the xenon. These measurements together are what determine whether double beta decay happened, and whether the decay was likely to be neutrinoless.

    EXO-200 isn’t the only neutrinoless double beta decay experiment, but many of the others use solid detectors instead of liquid xenon. Dolinski got her start on the CUORE experiment, a large solid-state detector, but later changed directions in her research.

    CUORE experiment UC Berkeley
    CUORE experiment UC Berkeley

    “I joined EXO-200 as a postdoc in 2008 because I thought that the large liquid detectors were a more scalable solution,” she says. “If you want a more sensitive liquid-state experiment, you can build a bigger tank and fill it with more xenon.”

    Neutrinoless or not, double beta decay is very rare. A given xenon atom decays randomly, with an average lifetime of a quadrillion times the age of the universe. However, if you use a sufficient number of atoms, a few of them will decay while your experiment is running.

    “We need to sample enough nuclei so that you would detect these putative decays before the researcher retires,” says Martin Breidenbach, one of the EXO-200 project leaders and a physicist at the Department of Energy’s SLAC National Accelerator Laboratory.

    But the experiment is not just detecting neutrinoless events. Heavier neutrinos mean more frequent decays, so measuring the rate reveals the neutrino mass — something very hard to measure otherwise.

    Prior runs of EXO-200 and other experiments failed to see neutrinoless double beta decay, so either neutrinos and antineutrinos aren’t the same particle after all, or the neutrino mass is small enough to make decays too rare to be seen during the experiment’s lifetime. The current limit for the neutrino mass is less than 0.38 electronvolts—for comparison, electrons are about 500,000 electronvolts in mass.

    2
    SLAC National Accelerator Laboratory’s Jon Davis checks the enriched xenon storage bottles before the refilling of the TPC. Brian Dozier, Los Alamos National Laboratory

    Working in the salt mines

    Cindy Lin is a Drexel University graduate student who spends part of her time working on the EXO-200 detector at the mine. Getting to work is fairly involved.

    “In the morning we take the cage elevator half a mile down to the mine,” she says. Additionally, she and the other workers at WIPP have to take a 40-hour safety training to ensure their wellbeing, and wear protective gear in addition to normal lab clothes.

    “As part of the effort to minimize salt dust particles in our cleanroom, EXO-200 scientists also cover our hair and wear coveralls,” Lin adds.

    The sheer amount of earth over the detector shields it from electrons and other charged particles from space, which would make it too hard to spot the signal from double beta decay. WIPP is carved out of a sodium chloride deposit—the same stuff as table salt—that has very little uranium or the other radioactive minerals you find in solid rock caverns. But it has its drawbacks, too.

    “Salt is very dynamic: It moves at the level of centimeters a year, so you can’t build a nice concrete structure,” says Breidenbach. To compensate, the EXO-200 team has opted for a more modular design.

    The inadvertent shutdown provided extra challenges. EXO-200, like most experiments, isn’t well suited for being neglected for more than a few days at a time. However, Lin and other researchers worked hard to get the equipment running for new data this year, and the downtime also allowed researchers to install some upgraded equipment.

    The next phase of the experiment, nEXO, is at a conceptual stage based on what has been learned from EXO200. Experimenters are considering the benefits of moving the project deeper underground, perhaps at a facility like the Sudbury Neutrino Observatory (SNOlab) in Canada.
    SNOLAB, Sudbury, Ontario, Canada.
    SNOLAB
    SNOLAB, Sudbury, Ontario, Canada

    Dolinski is optimistic that if there are any neutrinoless double beta decays to see, nEXO or similar experiments should see them in the next 15 years or so.

    Then, maybe we’ll know if neutrinos and antineutrinos are the same and find out more about these weird low-mass particles.

    See the full article here .

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 2:57 pm on May 1, 2016 Permalink | Reply
    Tags: , , , , Neutrinos,   

    From Science Alert: “Astronomers might have finally detected where mysterious, extragalactic neutrinos are coming from” 

    ScienceAlert

    Science Alert

    29 APR 2016
    FIONA MACDONALD

    3
    NASA/DOE/LAT Collaboration

    Just over three years ago, physicists working in Antarctica announced they’d detected the first evidence of mysterious subatomic particles, known as neutrinos, coming from outside our galaxy. It was a huge moment for astrophysics, but since then, no one’s quite been able to figure out where those particles are coming from, and what’s sending them hurtling our way.

    Until now, that is – a team of astronomers has just identified the possible source of one these extragalactic visitors, and it appears that it started its journey to us nearly 10 billion years ago, when a massive explosion erupted in a galaxy far, far away (seriously, George Lucas couldn’t make this stuff up).

    Let’s step back for a second here though and explain why this is a big deal. Neutrinos are arguably the weirdest of the fundamental subatomic particles. They don’t have any mass, they’re incredibly fast, and they’re pretty much invisible, because they hardly ever interact with matter. Like tiny ghosts, billions of neutrinos per second are constantly flowing through us, and we never even know about it.

    In order to detect them, researchers have step up extravagant labs, like the IceCube Neutrino Observatory at the South Pole, where they wait patiently to capture glimpses of neutrinos streaking through the planet, and measure how energetic they are, to try to work out where they came from.

    U Wisconsin ICECUBE neutrino detector
    IceCube neutrino detector interior
    U Wisconsin ICECUBE neutrino detector

    Usually that source is radioactive decay here on Earth or inside the Sun, or maybe from the black hole at the centre of our galaxy. But in 2013, the IceCube researchers announced they’d detected a couple of neutrinos so unimaginably energetic, they knew they must have come from outside our galaxy.

    These neutrinos were named ‘Bert’ and ‘Ernie’ (seriously) and they were the first evidence of extragalactic neutrinos. Their discovery was followed by the detection of a couple of dozen more, slightly less energetic, extragalactic neutrinos over the coming months.

    Then at the end of 2012, they spotted ‘Big Bird’. At the time it was the most energetic neutrino ever detected, with energy exceeding 2 quadrillion electron volts – that’s more than a million million times greater than the energy of a dental X-ray. Not bad for a massless ghost particle.

    Since then, teams across the world have been working to figure out where the hell this anomaly had come from. And now we might finally have a suspect.

    “It’s like a crime scene investigation,” said lead researcher Matthias Kadler from the University of Würzburg in Germany, “The case involves an explosion, a suspect, and various pieces of circumstantial evidence.”

    Using that circumstantial evidence, the best astronomers could do at the time was narrow the source down to a patch of the southern sky about 32 degrees across – roughly the size of 64 full moons.

    That sounds pretty specific, but an area that size in the night sky covers a whole lot of galaxies, and researchers had the tough job of sifting through all that data to figure out what happened in one of those galaxies to send Big Bird to us.

    They now think they have their answer – a huge explosion known as a blazar, which occurred in a galaxy called PKS B1424-418 around 10 billion years ago, but was only detected by our telescopes between 2011 and 2013 because of how far away it is.

    Blazar NASA Fermi Gamma ray Space Telescope Credits M. Weiss CfA
    Blazar. NASA Fermi Gamma ray Space Telescope. Credits M. Weiss/CfA

    A blazar is one of the most energetic events in the known Universe, and it occurs when a galaxy’s material falls towards the supermassive black hole at its centre, and some of that material ends up being blasted in huge jets directly towards Earth.

    Publishing* in Nature Physics, the team has now calculated that there’s only a 5 percent chance that Big Bird and the blazar at PKS B1424-418 coincidentally hit Earth at the same time, but weren’t linked.

    “Taking into account all of the observations, the blazar seems to have had means, motive and opportunity to fire off the Big Bird neutrino, which makes it our prime suspect,” said Kadler.

    The fact that these two individually fascinating events are associated is pretty exciting in itself.

    “There was a moment of wonder and awe when we realised that the most dramatic outburst we had ever seen in a blazar happened in just the right place at just the right time,” said co-author Felicia Krauß, from the University of Erlangen-Nürnberg.

    This hypothesis now needs to be independently verified before we can say for sure where Big Bird, and potentially other extragalactic neutrinos, come from. But it’s pretty exciting that we might finally, finally be getting close to understanding more about these enigmatic subatomic particles.

    Francis Halzen, who’s the principal investigator of IceCube, and wasn’t involved in this study, thinks the research heralds in an exciting new time in neutrino research.

    “IceCube is about to send out real-time alerts when it records a neutrino that can be localised to an area a little more than half a degree across, or slightly larger than the apparent size of a full moon,” he explains. “We’re slowly opening a neutrino window onto the cosmos.” Bring it on.

    *Science paper:
    Coincidence of a high-fluence blazar outburst with a PeV-energy neutrino event

    See the full article here .

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  • richardmitnick 2:42 pm on April 29, 2016 Permalink | Reply
    Tags: , , Neutrinos,   

    From Ethan Siegel: “Why Massive Neutrinos Are The Future Of Physics” 

    Starts with a bang
    Starts with a Bang

    Nov 3, 2015
    Ethan Siegel

    1
    Image credit: Tomasz Barszczak, via http://www.ps.uci.edu/~tomba/sk/tscan/compare_mu_e/.

    They won this year’s Nobel Prize in Physics, but their legacy’s just beginning.

    “I know all about neutrinos, and my friend here knows about everything else in astrophysics.” -John Bahcall, neutrino scientist

    If you want to describe the Universe we live in today, from a physical point of view, there are only three things you need to understand:

    What different types of particles are allowed to be present within it,
    What the laws are that govern the interactions between all those different particles, and
    What initial conditions the Universe starts off with.

    If you give a scientist all of those things and an arbitrary amount of calculational power, they can reproduce the entirety of the Universe we experience today, limited only by the quantum uncertainty inherent to our experience.

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

    SDSS Telescope at Apache Point, NM, USA
    SDSS Telescope at Apache Point, NM, USA

    In the 1960s, what we generally know as the Standard Model of elementary particles and their interactions came about, describing six quarks, three charged leptons, three massless neutrinos, along with the single photon for the electromagnetic force, the three W-and-Z bosons for the weak force, the eight gluons for the strong nuclear force, and the Higgs boson alongside them, to give mass to the fundamental particles in the Universe.

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

    Along with gravity, which is governed by Einstein’s general relativity, this accounts for the full suite of behavior of every individual particle ever directly detected.

    There are some mysteries that we don’t understand right now about the Universe, such as:

    why there’s more matter than antimatter,
    why there’s CP-violation in the weak interactions but not the strong interactions,
    what the nature of dark matter in the Universe is,
    why the fundamental constants and particle masses have the values they do,
    or where dark energy comes from.

    But for the particles that we have, the Standard Model does it all. Or rather, the Standard Model did it all, until we started looking closely at the almost invisible signals coming from the Sun: the neutrinos.

    Sun. Kelvinsong in Wikipedia
    Sun. Kelvinsong in Wikipedia

    The Sun is powered by nuclear fusion, where hydrogen nuclei are fused together at the tremendous temperatures and energies in the Sun’s core into helium. In the process, they emit large amounts of energy in the form of photons, and also energetic neutrinos. For every four protons that you fuse into a helium nucleus — the net result of fusion in the Sun — you produce two neutrinos. More specifically, you produce two anti-electron neutrinos, a very specific flavor of neutrino.

    Yet when we compute how many neutrinos ought to be produced, and we calculate how many we ought to be able to observe on Earth given our current technology, we only see about a third of the expected number: around 34%.

    Borexino Solar Neutrino detector
    INFN/Borexino Solar Neutrino detector, Gran Sasso, Italy

    Throughout the 1960s, 70s, 80s and 90s, most scientists lambasted either the experimental procedures used to detect these neutrinos, or decried the model of the Sun, claiming that something must be wrong. Yet as both theory and experiment improved, these results held up. It was almost like the neutrinos were disappearing, somehow. There was a radical theory proposed, however: that there was some new physics beyond the Standard Model that was at play, giving a tiny but non-zero mass to all the neutrinos, which would allow them to mix together. When they pass through matter and interact — ever so slightly — with it, this mixing enabled one flavor of neutrino (electron, muon or tau) to oscillate into a different one.

    3
    Image credit: Wikimedia Commons user Strait.

    It was only when we gained the capabilities to detect these other flavors of neutrino, at both Super-Kamiokande and the Sudbury Neutrino Observatory, that we learned that these neutrinos weren’t missing after all, but were transforming from one flavor (the electron-type) into another (the muon or tau type)!

    Super-Kamiokande experiment Japan
    Super-Kamiokande experiment Japan

    SNOLAB, Sudbury, Ontario, Canada.
    SNOLAB, Sudbury, Ontario, Canada

    We now know that all the neutrinos generated are electron (anti)neutrinos, but by time they reach us on Earth, they’re split ⅓, ⅓, ⅓ between the three flavors. Moreover, we’ve measured their masses from these experiments, determining that they’re somewhere between about 1 and a few hundred milli-electron-Volts, or less than one millionth the mass of the next-lightest particle: the electron.

    4
    Image credit: Hitoshi Murayama of http://hitoshi.berkeley.edu/.

    Yes, neutrinos oscillate from one flavor to another, and yes, they have mass. But the real reason it matters is this: for the first time, we have evidence that the particles in the Standard Model — the known, discovered particles in the Universe — have properties that aren’t described by the Standard Model at all!

    There’s more physics out there to be discovered, and this is the first clue of what it might be. So while high energies and the LHC haven’t seen any signs of it, the lowest mass particles show us that there’s more out there than we currently know. And that’s a mystery that’s only expected to deepen the more closely we look.

    See the full article here .

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    “Starts With A Bang! is a blog/video blog about cosmology, physics, astronomy, and anything else I find interesting enough to write about. I am a firm believer that the highest good in life is learning, and the greatest evil is willful ignorance. The goal of everything on this site is to help inform you about our world, how we came to be here, and to understand how it all works. As I write these pages for you, I hope to not only explain to you what we know, think, and believe, but how we know it, and why we draw the conclusions we do. It is my hope that you find this interesting, informative, and accessible,” says Ethan

     
  • richardmitnick 9:02 pm on April 25, 2016 Permalink | Reply
    Tags: , , Neutrinos, Rapid City Journal,   

    From Rapid City Journal via SURF: “Neutrino project could bring elevated conveyor over downtown Lead” 

    SURF logo
    Sanford Underground levels

    Sanford Underground Research facility

    4.25.16

    1

    Apr 24, 2016
    Tom Griffith

    2

    LEAD | An experiment now in its infancy nearly a mile underground has the potential to put this former gold mining camp on the map as the home for groundbreaking science that could help unravel the mysteries of the universe.

    Plans for the groundbreaking project solidified some now that Congress is considering mark-ups in President Obama’s fiscal 2017 budget, which begins Oct. 1, that include $45 million for start-up of the Deep Underground Neutrino Experiment at Lead’s Sanford Underground Research Facility.

    FNAL LBNF/DUNE
    FNAL LBNF/DUNE
    FNAL DUNE Argon tank at SURF
    FNAL DUNE Argon tank at SURF

    The project received another dose of Congressional support last week when U.S. Sen. John Thune, R-S.D., added a provision to a sweeping energy bill that would create a new Congressional subcommittee within the National Science and Technology Council specifically focused on high energy physics projects like those underway in Lead.

    And the project could alter the look of downtown Lead, where a proposal has been made to build an elevated conveyor system across Main Street to carry an estimated 800,000 tons of waste rock from the lab site into the open cut at Homestake Gold Mine.

    While the two acronyms — DUNE and SURF — seem like attractions of a beachfront holiday, they in fact represent man’s most serious attempts to date to understand the origins of our planet. The proposed DUNE project alone involves a collaboration of more than 800 scientists from roughly 150 institutions in 28 countries and with a price-tag estimated at $1 billion to $1.4 billion, about half of which would be spent in the Black Hills.

    That would make it the largest, most expensive project in South Dakota history.

    “I don’t think you could state the importance of the project too strongly,” said Mike Headley, executive director of the South Dakota Science and Technology Authority. “This is an international science mega-project. If you look at the current suite of experiments around the world and those planned in the future, this would be the largest in scale.

    “To draw a parallel, it would include international involvement on the scale of the Large Hadron Collider in Cern, Switzerland, where the Higgs Boson was discovered,” Headley added.

    CERN/LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    The Sanford Lab, occupying the massive 8,000-foot deep former Homestake Gold Mine which operated for 125 years in Lead, and the SDSTA have spent years planning for the DUNE, to be placed at the Long Baseline Neutrino Facility construction site at the 4,850-foot level.

    Sanford Underground Research Facility Interior
    Sanford Underground levels
    SURF

    In fact, private, state and federal funds are being used to refurbish the Ross Shaft, a $30 million project begun in August 2012, now 70 percent complete, that’s on track for completion in September 2017, Headley explained.

    Reconstruction of the Ross Shaft is critical to making room for the DUNE, which would require contractors to excavate 800 million tons of rock — nearly twice that removed from Mount Rushmore in the 1927-1941 carving of the four presidential portraits.

    All of that rock has to go someplace, so SURF has already reached an easement agreement with Barrick, the Canadian-based owners of the former Homestake Mine and its massive Open Cut, to deposit the excavated rock in the open pit. But, for some, getting it there has become an issue.

    SURF recently requested an easement from the city of Lead allowing it to build an elevated, covered conveyor spanning Main Street near Gold Run Park to transport the rock to its final resting place in the open cut. Representatives of SURF, including Headley, have appeared at the last two Lead City Commission meetings to provide project overviews and answer questions and concerns.

    “I do have a few concerns regarding the decision to construct a conveyor belt across a major highway that is a main thoroughfare for our community,” said Commissioner Denise Parker. Many of those concerns, including potential dust, debris and noise, have been brought to her attention by local residents, she said.

    “While I know that the lab officials are taking every precaution they can think of, there are no guarantees as to the outcomes and as of today, I have seen no memorandum of understanding stating the parameters of liabilities,” Parker noted. “I am deeply concerned that there is no definitive tear-down schedule after the digging and rock moving evolution is completed and there is no longer a need for the conveyor belt.”

    Headley said excavation and onsite construction during the peak of activity in the early 2020s, could bring 180 new workers to the SURF on a daily basis, including construction contractors, scientists and other partners. Those workers would not necessarily be added to the 130 employees the Science Authority currently employs at the SURF, he said.

    Parker said she would welcome new jobs in a town depressed since the closure of the Homestake in 2002, and the potential for the DUNE to put her community on the map of ground-breaking science.

    “When I think that our small community may very well be on the cutting edge of the science of tomorrow, it is almost incomprehensible,” she said. “When one hears of Los Alamos, they think of atomic and hydrogen bombs. I can only wonder what future generations potentially could think of when they hear of the city of Lead, South Dakota; hopefully, something synonymous with peace.”

    Mayor-Elect Ron Everett, contacted last week, said he believed SURF’s plan for a conveyor was preferable to another option SURF explored to remove the tons of rock that could lead to 40,000-60,000 round-trip truck loads to move the rock to another site.

    “There have been some concerns expressed about dust and what (the overhead conveyor) will look like, but I am all in favor of granting the easement,” said Everett, who assumes the mayor’s post May 2. “It’s the safest and most efficient way to move that rock out of the mine.”

    Everett, who recently retired as an executive with mining company Wharf Resources, said he views it as his mission to have Lead capitalize on all of the employment, housing and economic development potential of what the DUNE can bring to the Northern Hills.

    “I think people ought to be very excited about the DUNE project,” he said. “It will be an exciting time for Lead over the next 10 years and we want to capitalize on all the economic benefits that will come with this. We want good paying jobs in Lead.”

    Headley said city officials and others naturally gravitate to the economic development, employment and financial aspects of the DUNE. But, he said local residents shouldn’t discount the educational opportunities that students at schools and universities throughout the South Dakota and the U.S. would experience from the collaboration of scientists and advanced experiments coming to the Black Hills.

    “Folks may not think what could potentially happen here in the next few years in terms of educational opportunities, and the advancement of STEM (Science, Technology, Engineering, Mathematics) education for grades K-12,” Headley said.

    “The education of our kids is an area that will be profoundly and positively impacted as this project moves forward. After all, we have the brightest minds on the planet coming here to do their life’s work.”

    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. 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 11:46 am on April 21, 2016 Permalink | Reply
    Tags: , FNAL ANNIE, Neutrinos   

    From FNAL: “ANNIE finds a home at Fermilab” 

    FNAL II photo

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

    April 20, 2016
    Rashmi Shivni

    FNAL ANNIE
    Carrie McGivern prepares photomultiplier tubes during the ANNIE detector assembly. Photo: Reidar Hahn

    If you’ve passed by the old SciBooNE hall at Fermilab in the last couple of months, you might have heard a bit of commotion. A little experiment with big ambitions just finished moving in this week after a year’s worth of planning and research. The Accelerator Neutrino-Neutron Interaction Experiment, called ANNIE, recently settled down and began taking phase one data on April 15.

    “We want to better understand the nature of neutrino interactions by looking at their effects on an atom’s nucleus,” said Matthew Wetstein, a co-spokesperson for the ANNIE project and a Fermilab visiting scientist from Iowa State University. ANNIE will be the first realization of a new kind of detector in a large neutrino experiment. The technology will help look for particle interactions that are hard to distinguish in other detectors, he said.

    The ANNIE team aims to study phenomena and techniques relevant to neutrino energy and proton decay measurements through the use of a water Cherenkov detector loaded with a chemical element called gadolinium and surrounded by never before used photosensors called large-area picosecond photodetectors (LAPPDs).

    Light travels slower in a medium such as glass, water or other transparent materials than in air or in a vacuum. Sometimes, light travels slow enough in these materials that particles can overtake it. That’s why Cherenkov detectors are common in neutrino experiments. When neutrinos hit atoms in such media, the resulting free-flying electrically charged particles emit their own light, known as Cherenkov radiation, and these detectors record this light, allowing scientists to identify the type of particle and calculate its energy. In ANNIE’s case, neutrinos streaming down the Fermilab Booster Neutrino Beam will strike water molecules in the detector and knock off neutrons. Neutrons are electrically neutral and do not emit Cherenkov radiation, so they need to be detected some other way. After the initial neutrino-nucleus collisions, the gadolinium salts in the water effectively capture the neutrons and subsequently emit photons, which can be detected by photosensors.

    “Neutrons have always been a challenging particle to detect,” Wetstein said. “We hope ANNIE can determine how many neutrons are produced when neutrinos interact.”

    Observing this neutron release is useful because neutrons carry some energy with them that was transferred from the neutrino collision. Physicists believe higher-energy neutrino-nucleus interactions produce a larger number of knocked-off neutrons. To test this, ANNIE physicists will use accelerator-born neutrinos that have an energy level similar to atmospheric neutrinos, which have some of the highest-energy yields. The ANNIE team aims to understand how tagging free-flying neutrons can help them differentiate between a possible proton-decay signal and background noise from the neutrinos.

    1
    The ANNIE detector was lowered into the SciBooNE Building at Fermilab on February 29. Photo: Reidar Hahn

    One of the best ways for the team to determine the effects of neutron tagging is to use the LAPPDs, a photosensor technology that researchers had been developing for nearly five years prior to the 2015 proposal for ANNIE. These sensors are currently in the commercialization phase.

    LAPPDs are based on a technology called microchannel plates, which are tiny arrays with densely packed, tinier tubes that detect light. Conventional photodetectors, for physics research and commercial use, have single-pixel resolutions. In large neutrino experiments, these single-pixel phototubes can detect, for example, only one “blob” of charge coming from three separate photons in a neutrino-nucleus collision. Now with LAPPDs, scientists can read each individual photon, retrace where the photon came from and determine the time the light was emitted roughly 10 times better than previous photodetectors.

    Think of it as tracing photons’ movements at the scale of 50 to 60 trillionths of a second.

    High-precision timing with LAPPDs and accurate neutron tagging with the gadolinium-loaded water detector takes neutrino and proton-decay research to another level.

    Thirty collaborators, including postdoctoral researchers and students, were very active in building and installing the electronics, water systems and photodetection tubes.

    “We’ve done an excellent job of working together and making it happen as quickly as possible,” said Mayly Sanchez, a co-spokesperson for the ANNIE project and an Intensity Frontier fellow at Fermilab.

    Now that the ANNIE detector is in its home in the Fermilab SciBooNE building and taking data, the collaboration is preparing to analyze their results.

    “For phase one, we will be doing some neutrino background measurements for the ultimate physics measurements that we want to do,” Sanchez said. “The physics measurement in phase two will have an impact both in our knowledge of neutrino interactions and as the first application of a new photodetector technology in high-energy physics.”

    Phase one, supported by Fermilab, will continue until the Fermilab accelerator shutdown begins in July. The main physics experimentation and R&D studies will take place during phase two, which awaits funding. ANNIE researchers, supported by the U.S. Department of Energy Office of Science and the National Science Foundation, will later compare results from both phases to see what the experiment yields.

    “We learned what it takes to get an experiment like ANNIE off the ground at Fermilab,” Wetstein said. “I’m really proud that we got the whole thing from basically a big proposal to a fully designed experiment to turning all of our systems on within a year.”

    ANNIE’s collaborating institutions are Argonne National Laboratory, Fermilab, Iowa State University, Ohio State University, Queen Mary University of London, University of California, Berkeley, University of California, Davis, University of California, Irvine, University of Chicago and University of Sheffield.

    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 4:02 pm on April 19, 2016 Permalink | Reply
    Tags: , , Neutrinos,   

    From phys.org: “First high-energy neutrino traced to an origin outside of the Milky Way” 

    physdotorg
    phys.org

    1
    a, The Fermi/LAT γ-ray light curve is shown as two-week binned photon fluxes between 100 MeV and 300 GeV (black), the Bayesian blocks light curve (blue), and the HESE-35 time stamp (red line). The HESE period (May 2010 to May 2013) and the included outburst time range are highlighted in colour. Only statistical uncertainties are considered and shown at a 1 sigma confidence level.

    b, VLBI images show the core region at 8.4 GHz from 13 November 2011 (2011.87), 16 September 2012 (2012.71) and 14 March 2013 (2013.20) in uniform colour scale. 1 mas corresponds to about 8.3 pc. All contours start at 3.3 mJy beam−1 and increase logarithmically by factors of 2. The images were convolved with the enclosing beam from all three observations of 2.26 mas × 0.79 mas at a position angle of 9.5°, which is shown in the bottom left. The peak flux density increases from 1.95 Jy beam−1 (April 2011) to 5.62 Jy beam−1 (March 2013). Credit: Nature Physics (2016) doi:10.1038/nphys3715

    An international team of researchers has spotted the first instance of a high-energy neutrino collision from a source outside of the Milky Way, marking what they describe as a significant discovery. In their paper* published in the journal Nature Physics, the team describes their work at the South Pole Neutrino Observatory, the details pertaining to the sighting and why they believe their discovery may lead to a new era in neutrino astrophysics.

    U Wisconsin ICECUBE neutrino detector
    IceCube neutrino detector interior
    U Wisconsin ICECUBE neutrino detector

    Neutrino’s are massless and have no charge and very seldom interact with other matter—the exception is when they collide head on with another particle. Scientists have been studying neutrinos for several years, believing that they may hold the key to understanding many parts of the universe that remain otherwise hidden from our view. To see evidence of them, researchers fill large underground tanks with different types of fluids and then use extremely sensitive sensors to capture very brief flashes of light which are emitted when a neutrino collides with something in the fluid. The team with this latest effort has taken a different approach, they have placed sensors around a kilometer sized ice cube 2.5 kilometers beneath the surface, in a location near the South Pole. The sensors capture the brief flashes that occur when neutrinos collide with particles in the ice.

    Capturing evidence of collisions does not happen very often, but when it does, it sets off a chain of events that center around trying to ascertain where the neutrino came from—most come from the sun or cosmic rays striking our atmosphere. But back in 2012, the team captured evidence of what they described as the most powerful yet, registering two petavolts. Following that discovery, the team used data from radio telescopes, and in particular data from a galaxy that has been named KS B1424-418—astrophysicists have been studying it for several decades and it had been observed to undergo a change in shape during the time period 2011 to 2014. After much analysis, the team confirmed that the neutrino collision they observed was due to an emission from that very galaxy, making it the first neutrino collision to be traced back to a source outside of the Milky Way.

    Science paper:
    Coincidence of a high-fluence blazar outburst with a PeV-energy neutrino event

    See the full article here .

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    Stem Education Coalition

    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
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