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  • 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 .

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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 .

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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 .

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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 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 .

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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 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

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    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.

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    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.

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    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

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    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

    Stem Education Coalition

    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 1:58 pm on January 9, 2017 Permalink | Reply
    Tags: , Ellen Sandor, FNAL Art Gallery, FNAL Artist-in-residence program, Neutrinos, Neutrinos in a New Light, Science on display   

    From FNAL: “Visualizing the invisible” 

    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 9, 2017
    Ricarda Laasch

    Far beyond the realm of the visible, trillions of neutrinos rush through us every second and leave without a trace. Even large instruments for detecting these elusive particles have to be built with incredible sensitivity to be able to see them.

    Visualizing neutrinos was the challenge Ellen Sandor, a Chicago new-media artist and director of (art)n, and her team, Chris Kemp and Diana Torres, faced when she became Fermilab’s 2016 artist-in-residence.

    In her exhibit Neutrinos in a New Light, currently on display in the Fermilab Art Gallery, Sandor’s 3-D PHSColograms offer a new perspective on neutrinos and their detection in Fermilab’s various experiments. Sandor’s trademarked PHSColograms display abstract digital art while creating the illusion of depth, similar to a hologram.

    In one of her works, Sandor shows how Fermilab’s NOvA experiment measures neutrino traces left in NOvA’s detector.

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

    Sandor says she visualized the neutrinos data as a grid, inspired by op-art artist Victor Vasarely, of colors and shapes in the center of a so-called projection mapping of the detector.

    Sandor also created a virtual-reality interior of the detector for Fermilab’s MicroBooNE experiment.

    FNAL/MicrobooNE
    FNAL/MicrobooNE

    During scheduled tours of the exhibit, visitors can virtually submerge themselves in it, collide neutrinos with the material inside the detector, and see the resulting traces depicted as brush strokes or constructed sculptures.

    “We could even include a little art history: The paint brush strokes and sculptures are inspired by works of Jackson Pollock and David Smith,” Sandor said. The work of both American artists happens to be contemporary with discovery of neutrinos in 1956.

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    Sandor’s PHSCologram “Neutrinos and NOvA: A Vasarely Variation” captures the inner workings and produced data of the Fermilab neutrino detector NOvA. Image: (art)n

    Science on display

    Sandor’s residency work was a response to a request: Could she and her team create compelling art pieces on neutrinos and neutrino research at Fermilab?

    “We didn’t know anything about neutrinos when we accepted the residency,” Sandor said. “But we already had experience in visualizing the invisible – we visualized mathematical fractal maps in 4-D PHSColograms back in the 1980s. So we decided: Let’s learn about neutrinos.”

    The first steps in her journey to learn more about the mysterious particles brought her deep underground, where she came face-to-face with Fermilab’s large neutrino detectors. She also met with experts to discuss neutrinos and their ghostly behavior in detectors.

    FNAL DUNE Detector prototype
    FNAL DUNE Detector prototype

    Neutrinos are known for how little they interact with matter. They can pass through light-years of lead before striking a lead atom. And they could hold the clue to why, early in the universe’s formation, matter dominated over antimatter, leading to the bigger question of why we’re here at all.

    “We wanted our art to be 100 percent scientifically correct, but we also wanted to use metaphors,” Sandor said. “So we made sure that we got feedback from the scientists during the whole creation process.”

    One of her more metaphoric works, Allies for Antineutrinos, illustrates an international agreement to monitor antineutrinos created in nuclear reactors as two hands holding each other and releasing the particles. The piece is based on the work of the International Atomic Energy Agency, a watchdog for countries using nuclear power. One of its goals is to measure antineutrino levels next to nuclear reactors.

    Fermilab physicists helped Sandor in her presentation of the science and were open to her artistic visualization of their work. Her goal, in turn, was to allow scientists to see their work in a new light.

    “When I started the artist-in-residence program, I thought that this would be great for the artist,” said Georgia Schwender, curator of the Fermilab Art Gallery. “What I didn’t realize then was how important it also is to the scientists.”

    Sam Zeller, co-spokesperson for Fermilab’s MicroBooNE neutrino experiment, said she was able to see her own neutrino detector and how it functions in a very different light thanks to Sandor’s artwork. But she was even more interested to see how others interacted with the art pieces since she had been part of Sandor’s process as one of her scientific advisors.

    “The most impressive part for me was that no idea was too big for Ellen,” Zeller said. “Working with (art)n was much like working in particle physics: You dream up a bold new idea, brainstorm on how you could possibly pull it off – often changing directions as you go – and then you do it.”

    Neutrinos in a New Light will be on display until March 17. The virtual-reality exhibit of the MicroBooNE detector is accessible only during scheduled tours. You can take tours of the exhibit on Jan. 14, Feb. 18 and March 11 from 10 a.m.-noon.

    3
    “The Magnificent MicroBooNE” takes the visitors inside the large MicroBooNE detector and lets them experience science through visualization. Image: (art)n

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    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 12:35 pm on January 8, 2017 Permalink | Reply
    Tags: , , Neutrinos,   

    From U Wisconsin IceCube: “Week 52 at the Pole” 

    icecube
    U Wisconsin IceCube South Pole Neutrino Observatory

    06 Jan 2017
    Jean DeMerit

    1
    Gwenhael De Wasseige, IceCube/NSF

    The year’s end doesn’t mean an end to the work going on at the Pole. Last week, continued detector upgrades and some inventory tasks were on the work roster. There was also considerable progress made on a new IceTop snow-depth sensor project, documented in the image above. New Year’s Eve was celebrated with a festive party in the gym. And the traditional unveiling of the new geographic South Pole marker was held the next day. Tired or not from the previous night’s festivities, plenty of folks showed up for the event—and many hands made light work of moving the sign close to the new marker. A beautiful day for photos, and winterover James along with other Georgia Tech alumni seized on the opportunity.

    All images below, Martin Wolf, IceCube/NSF

    2

    3

    4

    5

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    ICECUBE neutrino detector
    IceCube is a particle detector at the South Pole that records the interactions of a nearly massless sub-atomic particle called the neutrino. IceCube searches for neutrinos from the most violent astrophysical sources: events like exploding stars, gamma ray bursts, and cataclysmic phenomena involving black holes and neutron stars. The IceCube telescope is a powerful tool to search for dark matter, and could reveal the new physical processes associated with the enigmatic origin of the highest energy particles in nature. In addition, exploring the background of neutrinos produced in the atmosphere, IceCube studies the neutrinos themselves; their energies far exceed those produced by accelerator beams. IceCube is the world’s largest neutrino detector, encompassing a cubic kilometer of ice.

     
  • richardmitnick 3:22 pm on January 6, 2017 Permalink | Reply
    Tags: , , , Neutrinos   

    From Symmetry: “CERN ramps up neutrino program” 

    Symmetry Mag
    Symmetry

    01/06/17
    Sarah Charley

    1
    Maximilien Brice, CERN

    The research center aims to test two large prototype detectors for the DUNE experiment.

    FNAL LBNF/DUNE from FNAL to SURF
    FNAL LBNF/DUNE from FNAL to SURF

    [I know that I am not a scientist and basically know nothing. But it bothers me that CERN is doing ANY work for DUNE. The U.S. Congress killed the Superconducting Super Collider in 1993 and virtually ceded HEP to Europe. I got into this blog when I found out that 30% of the people at CERN were from the U.S. and our press did not cover anything like this. I know that neutrino research virtually saved FNAL from the scrap heap. I just wish that anything being done for DUNE was being done here in the U.S. in one of our great D.O.E. labs or our great universities like MIT, Hopkins, Caltech, Illinois.]

    In the midst of the verdant French countryside is a workshop the size of an aircraft hangar bustling with activity. In a well lit new extension, technicians cut through thick slices of steel with electric saws and blast metal joints with welding torches.

    Inside this building sits its newest occupant: a two-story-tall cube with thick steel walls that resemble castle turrets. This cube will eventually hold a prototype detector for the Deep Underground Neutrino Experiment, or DUNE, the flagship research program hosted at the Department of Energy’s Fermi National Accelerator Laboratory [FNAL] to better understand the weird properties of neutrinos.

    Neutrinos are the second-most abundant fundamental particle in the visible universe, but because they rarely interact with atoms, little is known about them. The little that is known presents a daunting challenge for physicists since neutrinos are exceptionally elusive and incredibly lightweight.

    They’re so light that scientists are still working to pin down the masses of their three different types. They also continually morph from one of their three types into another—a behavior known as oscillation, one that keeps scientists on their toes.

    “We don’t know what these masses are or have a clear understanding of the flavor oscillation,” says Stefania Bordoni, a CERN researcher working on neutrino detector development. “Learning more about neutrinos could help us better understand how the early universe evolved and why the world is made of matter and not antimatter.”

    In 2015 CERN and the United States signed a new cooperation agreement that affirmed the United States’ continued participation in the Large Hadron Collider research program and CERN’s commitment to serve as the European base for the US-hosted neutrino program. Since this agreement, CERN has been chugging full-speed ahead to build and refurbish neutrino detectors.

    “Our past and continued partnerships have always shown the United States and CERN are stronger together,” says Marzio Nessi, the head of CERN’s neutrino platform. “Our big science project works only because of international collaboration.”

    The primary goal of CERN’s neutrino platform is to provide the infrastructure to test two large prototypes for DUNE’s far detectors. The final detectors will be constructed at Sanford Lab in South Dakota. Eventually they will sit 1.5 kilometers underground, recording data from neutrinos generated 1300 kilometers away at Fermilab.

    Two 8-meter-tall cubes, currently under construction at CERN, will each contain 770 metric tons of liquid argon permeated with a strong electric field. The international DUNE collaboration will construct two smaller, but still large, versions of the DUNE detector to be tested inside these cubes.

    In the first version of the DUNE detector design, particles traveling through the liquid knock out a trail of electrons from argon atoms. This chain of electrons is sucked toward the 16,000 sensors lining the inside of the container. From this data, physicists can derive the trajectory and energy of the original particle.

    In the second version, the DUNE collaboration is working on a new type of technology that introduces a thin layer of argon gas hovering above the liquid argon. The idea is that the additional gas will amplify the signal of these passing particles and give scientists a higher sensitivity to low-energy neutrinos. Scientists based at CERN are currently developing a 3-cubic-meter model, which they plan to scale up into the much larger prototype in 2017.

    In addition to these DUNE prototypes, CERN is also refurbishing a neutrino detector, called ICARUS, which was used in a previous experiment at the Italian Institute for Nuclear Physics’ Gran Sasso National Laboratory in Italy.

    INFN Gran Sasso ICARUS
    INFN Gran Sasso ICARUS

    FNAL/ICARUS
    FNAL/ICARUS

    ICARUS will be shipped to Fermilab in March 2017 and incorporated into a separate experiment.

    CERN plans to serve as a resource for neutrino programs hosted elsewhere in the world as scientists delve deeper into this enigmatic niche of particle physics.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 12:54 pm on November 30, 2016 Permalink | Reply
    Tags: , , , MicroBooNE, Neutrinos, ,   

    From FNAL: “Handy and trendy: MicroBooNE’s new look” 

    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.

    November 30, 2016
    Ricarda Laasch

    1
    MicroBooNE’s shiny new exterior helps scientists identify cosmic rays masquerading as neutrinos. From left: Elena Gramellini, Thomas Mettler. Martin Auger, Mark Shoun, John Voirin. Photo: Reidar Hahn

    The signals of cosmic rays

    Cosmic rays are a constant rain of particles that are created in our sun or faraway stars and travel through space to our planet.

    They’re subjects of many important physics studies, but for MicroBooNE’s research, they simply get in the way. That’s because MicroBooNE scientists are looking for something else — abundant, subtle particles called neutrinos.

    FNAL/MicrobooNE
    FNAL/MicrobooNE

    Unlocking the secrets neutrinos hold could help us understand the evolution of our universe, but they’re exceedingly difficult to measure. Fleeting neutrinos are rarely captured, even as they sail through detectors built for that purpose.

    Add to that the fact that their interactions are potentially drowned in a sea of cosmic rays rushing through the same detector, and you get a sense of the formidable challenge that neutrinos represent.

    The MicroBooNE experiment starts with Fermilab’s powerful accelerators, which create neutrino beams that are then propelled through the MicroBooNE detector.

    2
    July 8, 2015 Fermilab’s Main Injector accelerator, one of the most powerful particle accelerators in the world, has just achieved a world record for high-energy beams for neutrino experiments. Photo: Fermilab

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    Fermilab’s accelerator complex comprises seven particle accelerators and storage rings. It produces the world’s most powerful, high-energy neutrino beam and provides proton beams for a variety of experiments and R&D programs.

    Fermilab is currently upgrading its accelerator complex to deliver high-intensity neutrino beams and to provide beams for a broad range of new and existing experiments, including the Long-Baseline Neutrino Experiment, Muon g-2 and Mu2e.

    “The neutrino beam here at the lab gives us the right conditions to study neutrinos,” said Elena Gramellini, a Yale University graduate student on the MicroBooNE experiment. “Our challenge is to pick out neutrinos from many cosmic rays passing through the detector.”

    Since cosmic rays are made of some of the same particles produced when a neutrino interacts with matter, they leave signals in the MicroBooNE detector that are often similar to the sought-after neutrino signals. Scientists need to be able to sort the cosmic rays in the MicroBooNE data from the neutrino signals.

    Tagging and sorting

    Even several feet of concrete enclosure would not completely block cosmic rays from hitting a detector such as MicroBooNE, not to mention that such a structure would be inconvenient and expensive. Instead, MicroBooNE uses the aforementioned panels, called a cosmic ray tagger, or CRT. While the panels don’t block cosmic rays, they do detect them.

    Each CRT panel has particle-detecting components – strips of scintillator – that lie beneath its shiny aluminum enclosure. Cosmic ray particles can easily pass through aluminum and the scintillator — a clear, plastic-like material — on their way toward the MicroBooNE detector.

    The cosmic ray particles deposit energy in the plastic scintillator, which then emits light. An optical fiber buried inside the scintillator captures the emitted light and transmits it to devices that generate the digital information that tells scientists where and when the cosmic ray struck.

    “With our current layout of scintillator strips in each panel, we are able to tell precisely where the cosmic ray enters the MicroBooNE detector after it left the panel,” said Igor Kreslo, professor at the University of Bern who designed the CRT panels for MicroBooNE. “Our design effort really paid off and now ensures thorough cosmic ray tracking.“

    So why the shiny aluminum shell? It blocks unwanted light from the detector’s immediate surroundings so that only light created by cosmic rays inside a CRT panel reaches the optical fiber and is detected.

    Putting up panels

    The 49 rectangular CRT panels are the contribution of the University of Bern in Switzerland, one of the 28 institutions collaborating on MicroBooNE worldwide. They produced the panels last winter and shipped them to Fermilab during the spring.

    “This was a large project for us, and it took everyone in Bern to finish everything in time,” said Martin Auger, scientist at the University of Bern who planned the arrangement of the CRT panels. “A key moment was the test of the CRT panels after the long journey to Fermilab. All the panels arrived in good shape!”

    The installation team overcame a number of challenges —including the tight space in which MicroBooNE stands — to successfully place the panels around the detector.

    “The installation crew is a crack team of veteran Fermilab employees,” said John Voirin, who leads experiment installations at the laboratory. “In the end we have a very elegant, safe operating product that is a valuable asset to the experiment.”

    Later this year the group will complete the installation by placing the final layer on top of the MicroBooNE detector. Even without it, the CRT already greatly enhances the capabilities of the experiment.

    “We started taking data just in time for the first neutrinos delivered to the experiment,” Gramellini said.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    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.

     
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