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  • richardmitnick 10:28 am on December 24, 2019 Permalink | Reply
    Tags: GERDA- MPG GERmanium Detector Array at Gran Sasso Italy, LEGEND-200 the Large Enriched Germanium Experiment for Neutrinoless ββ Decay, Majorana demonstrator,   

    From Sanford Underground Research Facility: “Peering behind the MAJORANA DEMONSTRATOR shield” 

    SURF logo
    Sanford Underground levels

    From Sanford Underground Research Facility


    Homestake Mining Company

    December 19, 2019
    Erin Broberg

    1
    When researchers with the Majorana Demonstrator pulled back the layers of shielding earlier this month, the cryostat modules were visible for the first time in nearly four years. Photo by Nick Hubbard

    For the past 1,204 days, detectors have been collecting data, silent and undisturbed, inside a fortress of lead and copper shielding a mile beneath the earth’s surface. This December, researchers with the Majorana Demonstrator (Majorana) pulled back a piece of that shielding to peer inside.

    Housed on the 4850 Level of the Sanford Underground Research Facility (Sanford Lab), Majorana has been looking for a rare type of particle decay that could help us understand the existence of matter in the universe. Just how rare is this proposed physics event? To observe it in just two atoms, you’d have to wait over 2 x 1025 years — that’s a 2 followed by 25 zeroes.

    To better their chances of witnessing this elusive event in our lifetime, researchers proposed an experiment. This experiment would house a large concentration of atoms with the potential to see this rare decay. It would also have an extremely low background, protected from radiation by layers of shielding and rock overburden.

    Majorana demonstrated that such an experiment is possible. While it didn’t detect the particle decay, it proved that a scaled-up experiment—one that is more than 33 times its size—might be able to do so.

    “If we watch just one atom, waiting anxiously for it to decay, we would have to watch it for longer than the age of the universe. To win this game, we have to increase the mass we are watching,” said Vincent Guiseppe, co-spokesperson of the Majorana Collaboration and a research staff member at Oak Ridge National Laboratory. Majorana used 30 kilograms of an enriched isotope of germanium in its detector; the next-generation experiment, called LEGEND-200, will use 200 kilograms.

    2
    Guiseppe explains how layers of shielding protect the detectors from background “noise,” such as trace amounts of dust and radiation. Photo by Nick Hubbard

    LEGEND-200, the Large Enriched Germanium Experiment for Neutrinoless ββ Decay, will be built beneath the mountains of Italy at Gran Sasso National Laboratory (LNGS). To create the next phase of this international rare-event search, members of the Majorana collaboration joined with GERDA, another neutrinoless double-beta decay experiment using the same enriched isotope of germanium at LNGS, and other researchers.

    2

    While still taking valuable physics data, Majorana is pivoting to a new purpose: testing the detectors that will be used in LEGEND-200. This new use is one reason for the shield’s long-awaited opening. Researchers will replace five of Majorana’s detectors with four newly fabricated detectors for LEGEND-200.

    Gran Sasso LABORATORI NAZIONALI del GRAN SASSO, located in the Abruzzo region of central Italy

    To create the next phase of this international rare-event search, members of the Majorana collaboration joined with GERDA, another neutrinoless double-beta decay experiment using the same enriched isotope of germanium at LNGS, and other researchers.

    MPG GERmanium Detector Array (GERDA) at Gran Sasso, Italy

    Each detector is unique. Grown as crystals through a process called “pulling,” each has a slightly different height and diameter. By running tests underground and inserting the detectors into Majorana, researchers will better understand their performance in LEGEND-200.

    “Majorana is the lowest background environment we have,” said John Wilkerson, principal investigator for Majorana and U.S. principal investigator for LEGEND-200. “By installing them inside, we can further characterize the detectors, while also increasing our total physics data taken before Majorana is decommissioned.”

    Opening the shield was a week-long event. Researchers removed an outer 12-inch layer of heavy plastic, then slowly drew back an entire wall of the shield. The section that was removed included a module holding 22 kilograms of suspended germanium, 7 tons of lead and copper shielding and countless pieces of connectivity hardware. This interconnected equipment was air-skated to the opposite side of the laboratory.

    “The process of removing the wall took about half a morning,” Guiseppe said. “We had to move it incredibly slowly, so the detectors aren’t damaged.”

    On the other side of the lab space, the module was fitted inside a glove box. There, researchers removed five Majorana detectors and will soon replace them with four LEGEND-200 detectors. When the swap is complete, the detector module will be sealed up once again.

    3
    Inside a glovebox, Majorana’s germanium detectors hang suspended from an open cryostat module. Five of these detectors will be swapped with four newly-fabricated detectors for LEGEND-200. Photo by Nick Hubbard

    “This is the only time you can give each detector the TLC it needs to really understand its performance. Once you put them into the LEGEND-200 array, we will be operating all of them at once. Now is the time to get individualized information,” Guiseppe said. The opening also allowed the team to make upgrades to connectivity hardware.

    In addition to testing detectors, Majorana will provide ultra-pure copper and 35 enriched germanium detectors for LEGEND-200. When LEGEND-200 is built, the detectors will be packed in a special cargo container and shipped across the Atlantic Ocean. Finally, they will arrive at their final destination: 4,500 feet beneath Gran Sasso mountain in Italy.


    Majorana Demonstrator tests detectors for LEGEND-200

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

    About us.
    The Sanford Underground Research Facility in Lead, South Dakota, advances our understanding of the universe by providing laboratory space deep underground, where sensitive physics experiments can be shielded from cosmic radiation. Researchers at the Sanford Lab explore some of the most challenging questions facing 21st century physics, such as the origin of matter, the nature of dark matter and the properties of neutrinos. The facility also hosts experiments in other disciplines—including geology, biology and engineering.

    The Sanford Lab is located at the former Homestake gold mine, which was a physics landmark long before being converted into a dedicated science facility. Nuclear chemist Ray Davis earned a share of the Nobel Prize for Physics in 2002 for a solar neutrino experiment he installed 4,850 feet underground in the mine.

    Homestake closed in 2003, but the company donated the property to South Dakota in 2006 for use as an underground laboratory. That same year, philanthropist T. Denny Sanford donated $70 million to the project. The South Dakota Legislature also created the South Dakota Science and Technology Authority to operate the lab. The state Legislature has committed more than $40 million in state funds to the project, and South Dakota also obtained a $10 million Community Development Block Grant to help rehabilitate the facility.

    In 2007, after the National Science Foundation named Homestake as the preferred site for a proposed national Deep Underground Science and Engineering Laboratory (DUSEL), the South Dakota Science and Technology Authority (SDSTA) began reopening the former gold mine.

    In December 2010, the National Science Board decided not to fund further design of DUSEL. However, in 2011 the Department of Energy, through the Lawrence Berkeley National Laboratory, agreed to support ongoing science operations at Sanford Lab, while investigating how to use the underground research facility for other longer-term experiments. The SDSTA, which owns Sanford Lab, continues to operate the facility under that agreement with Berkeley Lab.

    The first two major physics experiments at the Sanford Lab are 4,850 feet underground in an area called the Davis Campus, named for the late Ray Davis. The Large Underground Xenon (LUX) experiment is housed in the same cavern excavated for Ray Davis’s experiment in the 1960s.

    LBNL LZ project at SURF, Lead, SD, USA, will replace LUX 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.

    LUX’s mission was to scour the universe for WIMPs, vetoing all other signatures. It would continue to do just that for another three years before it was decommissioned in 2016.

    In the midst of the excitement over first results, the LUX collaboration was already casting its gaze forward. Planning for a next-generation dark matter experiment at Sanford Lab was already under way. Named LUX-ZEPLIN (LZ), the next-generation experiment would increase the sensitivity of LUX 100 times.

    SLAC physicist Tom Shutt, a previous co-spokesperson for LUX, said one goal of the experiment was to figure out how to build an even larger detector.
    “LZ will be a thousand times more sensitive than the LUX detector,” Shutt said. “It will just begin to see an irreducible background of neutrinos that may ultimately set the limit to our ability to measure dark matter.”
    We celebrate five years of LUX, and look into the steps being taken toward the much larger and far more sensitive experiment.

    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.

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


    LBNE

    U Washington Majorana Demonstrator Experiment at SURF

    The MAJORANA DEMONSTRATOR will contain 40 kg of germanium; up to 30 kg will be enriched to 86% in 76Ge. The DEMONSTRATOR will be deployed deep underground in an ultra-low-background shielded environment in the Sanford Underground Research Facility (SURF) in Lead, SD. The goal of the DEMONSTRATOR is to determine whether a future 1-tonne experiment can achieve a background goal of one count per tonne-year in a 4-keV region of interest around the 76Ge 0νββ Q-value at 2039 keV. MAJORANA plans to collaborate with GERDA for a future tonne-scale 76Ge 0νββ search.

    CASPAR at SURF


    CASPAR is a low-energy particle accelerator that allows researchers to study processes that take place inside collapsing stars.

    The scientists are using space in the Sanford Underground Research Facility (SURF) in Lead, South Dakota, to work on a project called the Compact Accelerator System for Performing Astrophysical Research (CASPAR). CASPAR uses a low-energy particle accelerator that will allow researchers to mimic nuclear fusion reactions in stars. If successful, their findings could help complete our picture of how the elements in our universe are built. “Nuclear astrophysics is about what goes on inside the star, not outside of it,” said Dan Robertson, a Notre Dame assistant research professor of astrophysics working on CASPAR. “It is not observational, but experimental. The idea is to reproduce the stellar environment, to reproduce the reactions within a star.”

     
  • richardmitnick 12:43 pm on December 25, 2018 Permalink | Reply
    Tags: A primer on neutrinoless double-beta decay, , , Majorana demonstrator, , , Particles and antiparticles, , The matter-antimatter conudrum   

    From Sanford Underground Research Facility: “A primer on neutrinoless double-beta decay” 

    SURF logo
    Sanford Underground levels

    From Sanford Underground Research Facility

    December 21, 2018
    Erin Broberg

    We asked Vincente Guiseppe about this theorized phenomenon and what it means for our understanding of the universe.

    1
    Vince Guiseppe points to the center of the shield that houses Majorana’s detectors. Credit Matthew Kapust

    At Sanford Underground Research Facility, we often talk about the Majorana Demonstrator’s search for “neutrinoless double-beta decay.”

    U Washington Majorana Demonstrator Experiment at SURF

    We say that this process could be incredibly important to understanding the imbalance of matter and anti-matter in the early universe. We explain how it is difficult to detect, demanding a miniscule background. We show photos of germanium detectors and ultra-pure copper shields, then describe immaculate cleanrooms and show off stylish Tyvek garb.

    But what exactly is neutrinoless double-beta decay?

    To find out, we went directly to the source. Dr. Vincente Guiseppe is the co-spokesperson for the Majorana Demonstrator collaboration and an assistant professor of physics and astronomy at the University of South Carolina.

    The best way to explain this mysterious process, Guiseppe said, is to work backward, defining one word at a time. So, let’s start at the end.

    Decay

    “There are two types of isotopes,” Guiseppe explains, “stable and radioactive.”

    The nuclei of a stable isotope are relaxed, meaning, they have a very low energy state. The nuclei of a radioactive isotope, on the other hand, are in a high energy state—they are very excited. But objects in nature prefer to be relaxed, Guiseppe said.

    So how do nuclei achieve a lower energy state? Through radioactive decay.

    “In nuclear physics, decay means a relaxation or a change of an atomic nucleus,” Guiseppe explained. “Nature allows protons and neutrons to change their makeup to achieve a desirable equilibrium. Once a nucleus is at the lowest energy state, we call it a stable isotope.”

    A lot of times, the words “radioactive decay” sound threatening. That’s because they often are used in the context of radiation you don’twant—radiation that is dangerous or destructive. In reality, though, radioactive decays are taking place all the time.

    “Potassium 40 is an isotope in our bodies,” said Guiseppe. “These isotopes decay 200,000 times per minute.”

    Radioactive decay is simply a nucleus reconfiguring itself through an interplay of matter and energy. Researchers with Majorana are looking for a natural process in which nuclei undergo such a change.

    Double-beta

    Every time an isotope decays, it loses a bit of energy in the form of a particle. Scientists classify types of decays by defining what type of particle comes out of the decay. In the case of beta decay, the particle emitted is an electron, or a beta particle.

    While there are multiple types of decays that could occur within the detector, Majorana researchers are looking specifically for a decay in which a beta particle is emitted.

    “And by ‘double-beta,’ we just mean we are looking for two of these decays simultaneously,” Guiseppe said.

    Neutrino(less)

    All reactions in nature, including beta decays, require symmetry, or a balance. Because of this symmetry, scientists originally assumed that every time an isotope underwent beta decay, it would emit an electron with a uniform energy. The problem was, it didn’t.

    “Electrons emitted from beta decays have a range of energies,” Guiseppe said. “Sometimes it is low, sometimes it is high, but it has this average value that was more or less half of what the scientists thought it should be.”

    This inconsistency lead researchers to realize that there must be another particle emitted—one that could not easily be detected, having no charge and very little mass. That missing particle was a neutrino.

    “When neutrinos were discovered in 1956, their addition to the beta-decay equation was confirmed,” said Guiseppe. “The neutrino balances this fundamental symmetry. With beta decay, there has to be both an electron and a neutrino produced.”

    Hold on a second. By definition, a beta decay must have an electron. By the laws of physics, it must have a neutrino. So why is Majorana looking for neutrinoless double-beta decay?

    “I just spent all this time explaining why you need a neutrino for a beta decay,” Guiseppe said with a smile. “And now, I’m going to say, no, you might not need a neutrino every time.”

    Scientists, Guiseppe said, have good reason to believe that neutrinos have the ability to do something very interesting—the ability to act like anti-neutrinos.

    Neutrinos — the maverick of the early universe

    To better understand the theory, we must first examine what is called the matter and antimatter asymmetry problem.

    According to the Big Bang theory, when the universe first formed, it had equal parts of matter and antimatter. This is a conundrum because, when matter and antimatter meet, they annihilate, leaving a universe filled with pure energy—no planets, stars or comets. And, most certainly, no life.

    So, what happened? Why did matter win out in the cosmic battle? Scientists are seeking an answer to how matter became the dominant form of matter in the universe.

    Many scientists believe there must have been a particle—very much like a neutrino—that acted very inconsistently with our current understanding of the laws of physics. This inconsistency, if detected, could answer the matter and anti-matter asymmetry puzzle. If just one particle acted differently, it could have upset the balance and allowed a remnant of matter to survive.

    For most particles, there exists matter and anti-matter. These types of matter are mirror images of each other—100 percent different. In the early 1930s, however, physicist Ettore Majorana theorized that neutrinos could be their own anti-particle—or what we call today, a Majorana particle.

    3
    Ettore Majorana

    “The claim is that maybe there’s no difference between neutrinos and what we call anti-neutrinos. They may be indistinguishable from each other,” said Guiseppe. “If they have that quality, it could help explain matter and antimatter asymmetry.”

    Neutrinoless double-beta decay — putting it all together

    If neutrinos have this property, it could answer a lot of questions for scientists; for example, how matter became the dominant form of matter in the universe, allowing for the creation of everything we see. But how might Majorana help discover it?

    Researchers are waiting for a double-beta decay to occur inside the Majorana Demonstrator. If it does, and if neutrinos can indeed act like their own antiparticle, then the two neutrinos necessary may interact, possibly being absorbed, making the double-beta decay seem neutrinoless.

    “If two beta decays occur in the Majorana Demonstrator, in close proximity to each other, and neutrinos do have this property, then we will detect the absence of neutrinos,” Guiseppe said.

    Should this rare event be detected, it will require rewriting the Standard Model of Particles and Interactions, our basic understanding of the physical world.

    “What isn’t up for debate,” Guiseppe concluded, “is that if neutrinos are indistinguishable from their anti-particle, then they will allow this neutrinoless double-beta decay process to take place. If they have this property, we will see the decay in Majorana. This is the best type of experiment we have to learn that.”

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

    About us.
    The Sanford Underground Research Facility in Lead, South Dakota, advances our understanding of the universe by providing laboratory space deep underground, where sensitive physics experiments can be shielded from cosmic radiation. Researchers at the Sanford Lab explore some of the most challenging questions facing 21st century physics, such as the origin of matter, the nature of dark matter and the properties of neutrinos. The facility also hosts experiments in other disciplines—including geology, biology and engineering.

    The Sanford Lab is located at the former Homestake gold mine, which was a physics landmark long before being converted into a dedicated science facility. Nuclear chemist Ray Davis earned a share of the Nobel Prize for Physics in 2002 for a solar neutrino experiment he installed 4,850 feet underground in the mine.

    Homestake closed in 2003, but the company donated the property to South Dakota in 2006 for use as an underground laboratory. That same year, philanthropist T. Denny Sanford donated $70 million to the project. The South Dakota Legislature also created the South Dakota Science and Technology Authority to operate the lab. The state Legislature has committed more than $40 million in state funds to the project, and South Dakota also obtained a $10 million Community Development Block Grant to help rehabilitate the facility.

    In 2007, after the National Science Foundation named Homestake as the preferred site for a proposed national Deep Underground Science and Engineering Laboratory (DUSEL), the South Dakota Science and Technology Authority (SDSTA) began reopening the former gold mine.

    In December 2010, the National Science Board decided not to fund further design of DUSEL. However, in 2011 the Department of Energy, through the Lawrence Berkeley National Laboratory, agreed to support ongoing science operations at Sanford Lab, while investigating how to use the underground research facility for other longer-term experiments. The SDSTA, which owns Sanford Lab, continues to operate the facility under that agreement with Berkeley Lab.

    The first two major physics experiments at the Sanford Lab are 4,850 feet underground in an area called the Davis Campus, named for the late Ray Davis. The Large Underground Xenon (LUX) experiment is housed in the same cavern excavated for Ray Davis’s experiment in the 1960s.
    LUX/Dark matter experiment at SURFLUX/Dark matter experiment at SURF

    In October 2013, after an initial run of 80 days, LUX was determined to be the most sensitive detector yet to search for dark matter—a mysterious, yet-to-be-detected substance thought to be the most prevalent matter in the universe. The Majorana Demonstrator experiment, also on the 4850 Level, is searching for a rare phenomenon called “neutrinoless double-beta decay” that could reveal whether subatomic particles called neutrinos can be their own antiparticle. Detection of neutrinoless double-beta decay could help determine why matter prevailed over antimatter. The Majorana Demonstrator experiment is adjacent to the original Davis cavern.

    LUX’s mission was to scour the universe for WIMPs, vetoing all other signatures. It would continue to do just that for another three years before it was decommissioned in 2016.

    In the midst of the excitement over first results, the LUX collaboration was already casting its gaze forward. Planning for a next-generation dark matter experiment at Sanford Lab was already under way. Named LUX-ZEPLIN (LZ), the next-generation experiment would increase the sensitivity of LUX 100 times.

    SLAC physicist Tom Shutt, a previous co-spokesperson for LUX, said one goal of the experiment was to figure out how to build an even larger detector.
    “LZ will be a thousand times more sensitive than the LUX detector,” Shutt said. “It will just begin to see an irreducible background of neutrinos that may ultimately set the limit to our ability to measure dark matter.”
    We celebrate five years of LUX, and look into the steps being taken toward the much larger and far more sensitive experiment.

    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

    U Washington Majorana Demonstrator Experiment at SURF

    The MAJORANA DEMONSTRATOR will contain 40 kg of germanium; up to 30 kg will be enriched to 86% in 76Ge. The DEMONSTRATOR will be deployed deep underground in an ultra-low-background shielded environment in the Sanford Underground Research Facility (SURF) in Lead, SD. The goal of the DEMONSTRATOR is to determine whether a future 1-tonne experiment can achieve a background goal of one count per tonne-year in a 4-keV region of interest around the 76Ge 0νββ Q-value at 2039 keV. MAJORANA plans to collaborate with GERDA for a future tonne-scale 76Ge 0νββ search.

    LBNL LZ project at SURF, Lead, SD, USA

    CASPAR at SURF


    CASPAR is a low-energy particle accelerator that allows researchers to study processes that take place inside collapsing stars.

    The scientists are using space in the Sanford Underground Research Facility (SURF) in Lead, South Dakota, to work on a project called the Compact Accelerator System for Performing Astrophysical Research (CASPAR). CASPAR uses a low-energy particle accelerator that will allow researchers to mimic nuclear fusion reactions in stars. If successful, their findings could help complete our picture of how the elements in our universe are built. “Nuclear astrophysics is about what goes on inside the star, not outside of it,” said Dan Robertson, a Notre Dame assistant research professor of astrophysics working on CASPAR. “It is not observational, but experimental. The idea is to reproduce the stellar environment, to reproduce the reactions within a star.”

     
  • richardmitnick 9:17 am on September 19, 2017 Permalink | Reply
    Tags: , LEGEND 200, Majorana demonstrator, ,   

    From SURF: “Majorana Demonstrator: Preparing to scale up” 

    SURF logo
    Sanford Underground levels

    Sanford Underground Research facility

    September 11, 2017
    Constance Walter

    1
    John Wilkerson (left) and Cabot-Ann Christofferson work on the systems for the Majorana experiment, which sits inside a six-layered shield to block backgrounds. Photo by Matt Kapust

    For years, the Majorana Demonstrator laboratories and machine shop bustled with activity. Dozens of collaboration members worked on various elements of the experiment— from electroforming copper to building a shield to machining every component for the detectors and cryostats. Today, nestled deep within its six-layered shield, Majorana quietly collects data with just a handful of team members to ensure things are working.

    “We’ve made the transition from managing construction to overseeing an operation,” said Vince Guiseppe, assistant professor of physics at the University of South Carolina. “Since the winter, we’ve been running smoothly.”

    The Majorana Demonstrator uses natural and enriched germanium crystals to look for neutrinoless double-beta decay. Such a discovery could determine whether the neutrino is its own antiparticle.

    U Washington Majorana Demonstrator Experiment at SURF

    But the project is, first and foremost, a demonstrator, a research and development project built on a small scale to determine whether a 1-ton version is feasible, said Steve Elliott of Los Alamos National Laboratory. “For it to be feasible, we have to show that backgrounds can be low enough to justify building such a next-generation experiment.”

    Which Majorana has done, Guiseppe said. “We’ve only been running for about a year and we appear to be meeting those goals. Our backgrounds are excellent.”

    Guiseppe recently became a co-spokesperson for the project, along with Jason Detwiler of the University of Washington. The two replace Elliott, who will become co-spokesperson for LEGEND, the recently formed collaboration that will develop a much larger next-generation neutrinoless double-beta decay experiment

    The Large Enriched Germanium Experiment for Neutrinoless ββ Decay, or LEGEND, collaboration was formed a year ago and includes members of the Majorana Demonstrator collaboration, the GERDA (GERmanium Detector Array) collaboration, and other researchers in this field.

    3
    The GERDA experiment has been proposed in 2004 as a new 76Ge double-beta decay experiment at LNGS. The GERDA installation is a facility with germanium detectors made out of isotopically enriched material. The detectors are operated inside a liquid argon shield. The experiment is located in Hall A of LNGS.

    GERDA and Majorana are searching for the same thing, but they’ve used different technologies to reach their goals. For example, where Majorana used electroformed copper and built a complicated six-layered shield to keep backgrounds out, GERDA used commercial copper and shielded its detector inside a tank of liquid argon, which scintillates, or lights up, when backgrounds enter.

    And both are seeing what they hoped to see: low backgrounds. “They’ve done a lot of nice things, we’ve done a lot of nice things and there are some things we both did very well.” Guiseppe said. “And we’ve both demonstrated we can get the backgrounds we want. LEGEND will take the best features of each experiment.”

    The LEGEND collaboration wants to scale up to 1,000 kg of enriched germanium. By comparison, Majorana and GERDA each use approximately 30 kg in their experiments. But the plan is to start smaller, with a 200-kg experiment.

    “LEGEND 200 will be the first incarnation and will be the roadmap to get to the ton-scale experiment,” Guiseppe said.

    “The good news is we have a great collaboration with great people. We have a common vision and design and funding plans are moving forward. This is not something one of us can do alone. It’s important to have international partners.”

    Although he’s looking to the future, Guiseppe remains focused on the here and now. “Both GERDA and Majorana have to complete their life cycles,” he said. “And there’s still a lot we can learn from running our current experiments.”

    See the full article here .

    Please help promote STEM in your local schools.
    STEM Icon

    Stem Education Coalition

    About us.
    The Sanford Underground Research Facility in Lead, South Dakota, advances our understanding of the universe by providing laboratory space deep underground, where sensitive physics experiments can be shielded from cosmic radiation. Researchers at the Sanford Lab explore some of the most challenging questions facing 21st century physics, such as the origin of matter, the nature of dark matter and the properties of neutrinos. The facility also hosts experiments in other disciplines—including geology, biology and engineering.

    The Sanford Lab is located at the former Homestake gold mine, which was a physics landmark long before being converted into a dedicated science facility. Nuclear chemist Ray Davis earned a share of the Nobel Prize for Physics in 2002 for a solar neutrino experiment he installed 4,850 feet underground in the mine.

    Homestake closed in 2003, but the company donated the property to South Dakota in 2006 for use as an underground laboratory. That same year, philanthropist T. Denny Sanford donated $70 million to the project. The South Dakota Legislature also created the South Dakota Science and Technology Authority to operate the lab. The state Legislature has committed more than $40 million in state funds to the project, and South Dakota also obtained a $10 million Community Development Block Grant to help rehabilitate the facility.

    In 2007, after the National Science Foundation named Homestake as the preferred site for a proposed national Deep Underground Science and Engineering Laboratory (DUSEL), the South Dakota Science and Technology Authority (SDSTA) began reopening the former gold mine.

    In December 2010, the National Science Board decided not to fund further design of DUSEL. However, in 2011 the Department of Energy, through the Lawrence Berkeley National Laboratory, agreed to support ongoing science operations at Sanford Lab, while investigating how to use the underground research facility for other longer-term experiments. The SDSTA, which owns Sanford Lab, continues to operate the facility under that agreement with Berkeley Lab.

    The first two major physics experiments at the Sanford Lab are 4,850 feet underground in an area called the Davis Campus, named for the late Ray Davis. The Large Underground Xenon (LUX) experiment is housed in the same cavern excavated for Ray Davis’s experiment in the 1960s.
    LUX/Dark matter experiment at SURFLUX/Dark matter experiment at SURF

    In October 2013, after an initial run of 80 days, LUX was determined to be the most sensitive detector yet to search for dark matter—a mysterious, yet-to-be-detected substance thought to be the most prevalent matter in the universe. The Majorana Demonstrator experiment, also on the 4850 Level, is searching for a rare phenomenon called “neutrinoless double-beta decay” that could reveal whether subatomic particles called neutrinos can be their own antiparticle. Detection of neutrinoless double-beta decay could help determine why matter prevailed over antimatter. The Majorana Demonstrator experiment is adjacent to the original Davis cavern.

    Another major experiment, the Long Baseline Neutrino Experiment (LBNE)—a collaboration with Fermi National Accelerator Laboratory (Fermilab) and Sanford Lab, is in the preliminary design stages. The project got a major boost last year when Congress approved and the president signed an Omnibus Appropriations bill that will fund LBNE operations through FY 2014. Called the “next frontier of particle physics,” LBNE will follow neutrinos as they travel 800 miles through the earth, from FermiLab in Batavia, Ill., to Sanford Lab.

    Fermilab LBNE
    LBNE

     
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