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  • 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 .

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    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.

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    “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 .

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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 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

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    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

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    See the full article here .

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    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 .

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    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.

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    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.

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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 2:58 pm on November 29, 2016 Permalink | Reply
    Tags: , Neutrinos, , SNO+   

    From UC Davis: “SNO+ Neutrino Detector Gets Ready For Run” 

    UC Davis bloc

    UC Davis

    November 29th, 2016
    Andy Fell

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    SNO+ neutrino detector being filled with ultrapure water. The detector will search for neutrinos from distant supernovae and nuclear reactors. Credit: SNO+ Collaboration

    Not a still from a science fiction movie, but the SNO+ neutrino detector being filled with very pure water prior to starting operations. Located over a mile underground in a mine in Ontario, Canada, the SNO+ detector consists of an acrylic sphere 12 meters in diameter filled with 800 tonnes of scintillation fluid, floating in a bath of ultrapure water surrounded by 10,000 photomultiplier tubes that will detect flashes of light from passing neutrinos.

    The color in the photograph isn’t computer enhanced, said Professor Robert Svoboda, chair of the Department of Physics, who is a member of the SNO+ team.

    “The blue color comes from the fact the water is very pure – more than 10,000 times purer than Lake Tahoe,” Svoboda said.

    Svoboda and other UC Davis physicists, including graduate students Morgan Askins and Teal Pershing and postdocs Vincent Fischer and Leon Pickard, helped build SNO+ and will be working on analyzing data from the experiment. It will measure neutrinos from the Sun, from distant supernovae, and from nuclear reactors in the U.S. and Canada. It will search for a rare form of radioactivity, predicted but not yet observed, which would show whether neutrinos are different from other fundamental particles.

    SNO+ will be a new kilo-tonne scale liquid scintillator detector that will study neutrinos. The experiment will be located approximately 2km underground in VALE’s Creighton mine near Sudbury, Ontario, Canada. The heart of the SNO+ detector will be a 12m diameter acrylic sphere fill with approximately 800 tonnes of liquid scintillator which will float in a water bath. This volume will be monitored by about 10,000 photomultiplier tubes (PMTs), which are very sensitive light detectors. The acrylic sphere, PMTs and PMT support structure will be re-used from the SNO experiment. Therefore, SNO+ will look almost exactly the same as SNO (shown above) except that, in addition to the ropes that currently hold the acrylic vessel up, we will add ropes to hold the vessel down once it is filled with (buoyant) scintillator.

    Liquid scintillator is an organic liquid that gives off light when charged particles pass through it. SNO+ will detect neutrinos when they interact with electrons and nuclei in the detector to produce charged particles which, in turn, create light as they pass through the scintillator. The flash of light is then detected by the PMT array. This process is very similar to the way in which SNO detected neutrinos except that, in the SNO experiment, the light was produced through the Cherenkov process rather than by scintillation. It is this similarity in detection schemes that allows the SNO detector to be so efficiently converted for use as a liquid scintillator detector.

    The scintillator in the SNO+ experiment will be primarily composed of linear alkyl benzene (LAB), which is a new scintillator for this type of experiment. LAB was chosen because it has good light output, is quite transparent, and is a “nice” chemical to work with (it has properties much like those of mineral oil). It also seems to be compatible with acrylic (which is obviously important for SNO+). LAB is used commercially to manufacture of dish soap, among other things, which means that it is available in the large quantities needed for SNO+ at a relatively low price. As an added bonus, there is a plant in Quebec that produces very good LAB, meaning that SNO+ can have a “local supplier” of high quality scintillator.

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    People

    University of Alberta:
    A. Bialek, A. Hallin, M. Hedayatipoor, C. Krauss, P. Mekarski, L. Sibley, K. Singh, J. Soukup

    Armstrong Atlantic State University:
    J. Secrest

    University of California, Berkeley / LBNL:
    F. Descamps, C. Dock, G. Orebi Gann, K. Haghighi, K. Kamdin, T. Kaptanohku, P. McKenna, K. Nuckolls, C. Weisser

    Black Hills State University:
    K. Keeter

    Brookhaven National Laboratory:
    W.Beriguete, S. Hans, L. Hu, R. Rosero, M. Yeh, Y. Williamson

    University of California, Davis:
    M. Askins, C. Grant, R. Svoboda

    University of Chicago:
    E. Blucher, J. Cushing, K. Labe, T. LaTorre, M. Strait

    Dresden University of Technology:
    V. Lozza, B. von Krosigk, F. Krüger, M. Reinhard, A. Soerensen, K. Zuber

    Laurentian University:
    D. Chauhan, E.D. Hallman, C. Kraus, T. Shantz, M. Schwendener, C. Virtue

    LIP Lisbon and Coimbra:
    R. Alves, S. Andringa, L. Gurriana, A.Maio, J. Maneira, G. Prior

    University of Lancaster:
    H.Okeeffe, L. Kormos

    University of Liverpool:
    N.McCauley, H. J. Rose, R. Stainforth, J. Walker

    University of North Carolina at Chapel Hill:
    M.Howe, J. Wikerson

    Oxford University:
    S.Biller, I. Coulter, N. Jelley, C. Jones, J. Ligard, K. Majumdar, A. Reichold, L. Segui

    University of Pennsylvania:
    E. Beier, R. Bonventre, W.J. Heintzelman, J. Klein, P. Keener, R.Knapik, A. Mastbaum, T. Shokair, R. Van Berg

    Queen Mary, University of London:
    E. Arushanova, A. Back, S. Langrock, F. Di Lodovico, P. Jones, J. Wilson

    Queen’s University:

    S. Asahi, M. Boulay, M. Chen, N. Fatemi-Ghomi, P.J. Harvey, C. Hearns, A. McDonald, A. Noble, M. Seddighim, T. Sonley, E. O’Sullivan, P. Skensved, I. Takashi

    SNOLAB:
    C.Beaudoin, G. Bellehumeur, O. Chkvorets, B. Cleveland, F. Duncan, R. Ford, N. Gagnon, C. Jillings, S. Korte, I. Lawson, T. O’Malley, M. Schumaker, E. Vazquez-Jauregui

    University of Sheffield:
    J. McMillan

    University of Sussex:
    E. Falk, J. Hartnell, M. Mottram, S. Peeters, J. Sinclair, J. Waterfield, R. White

    TRIUMF:
    R. Helmer

    University of Washington:
    L. Kippenbrock, T. Major, J. Tatar, N. Tolich

    See the full article here .

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    UC Davis Campus

    The University of California, Davis, is a major public research university located in Davis, California, just west of Sacramento. It encompasses 5,300 acres of land, making it the second largest UC campus in terms of land ownership, after UC Merced.

     
  • richardmitnick 8:19 am on November 8, 2016 Permalink | Reply
    Tags: , , Neutrinos,   

    From FNAL: “Fermilab “deepens” its relationship with Sanford Underground Research Facility” 

    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 7, 2016

    1
    Along with Fermilab in Batavia, Illinois, Sanford Underground Research Facility in South Dakota is the site of the future Deep Underground Neutrino Experiment and its Long-Baseline Neutrino Facility. Pictured here is Ross Shaft. Photo: Sanford Underground Research Facility.

    The U.S. Department of Energy pursues discovery science that inspires and transforms our nation — research that can sometimes be pursued only in unique environments. The Sanford Underground Research Facility, owned and operated by the South Dakota Science and Technology Authority, or SDSTA, provides one such unique facility, with laboratories located 4,850 feet underground.

    SURF logo
    Sanford Underground levels
    SURF underground levels

    Because of the “deep” involvement of both Fermilab and Sanford Lab with the international Deep Underground Neutrino Experiment (DUNE), Fermilab has assumed a new role in the general services that support DOE science at the South Dakota facility.

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

    Starting Oct. 1, Fermilab became the point of contact for the Department of Energy Office of Science at Sanford Lab. In this role, Fermilab is the liaison between DOE and SDSTA. This represents the first time Fermilab has acted in this role for a facility outside Illinois.

    “We are excited about this transition as it brings our two organizations into closer partnership and strengthens the platform for some amazing DOE science,” said Tim Meyer, Fermilab chief operating officer.

    The change demonstrates recognition by the Department of Energy of the major role Fermilab will play in future Sanford Lab operations. Previously, Lawrence Berkeley National Laboratory acted as the point of contact for DOE at Sanford Lab. Berkeley Lab continues its leading role in dark matter experiments at the South Dakota lab.

    Fermilab and Sanford Lab are the sites of the future DUNE international particle physics experiment and the supporting Long-Baseline Neutrino Facility (LBNF).

    Fermilab, located in Batavia, Illinois, will send a beam of particles called neutrinos 1,300 kilometers (800 miles) through Earth to Sanford Lab. There, enormous particle detectors, located nearly a mile underground, will receive the neutrinos and send the data to scientists.

    Sanford Lab hosts multiple science experiments, of which DUNE is only one. The international Large Underground Xenon dark matter detector, known as LUX, has called Sanford Lab home.

    Lux Zeplin project at SURF
    Lux Zeplin project at SURF

    The Majorana Demonstrator neutrino experiment, run by a multinational team, is also conducted at Sanford Lab.

    Majorana Demonstrator Experiment
    Majorana Demonstrator Experiment

    The Department of Energy, the National Science Foundation and NASA all participate in the science experiments at the South Dakota lab.

    As the largest new project being undertaken in particle physics anywhere in the world since the Large Hadron Collider, LBNF/DUNE will be the most ambitious undertaking at Sanford Lab.

    “The SDSTA is proud to partner with Fermilab for the continued operations of the Sanford Lab,” said Mike Headley, executive director of SDSTA. “We’ve had a wonderful, productive relationship with Berkeley Lab, which was instrumental in creating the Sanford Lab — the deepest underground science facility in the United States.”

    See the full article here .

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    Fermilab Campus

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

     
  • richardmitnick 8:09 am on October 12, 2016 Permalink | Reply
    Tags: , , , , , Neutrinos, ,   

    From Symmetry: “Recruiting team geoneutrino” 

    Symmetry Mag
    Symmetry

    10/11/16
    Leah Crane

    1
    Illustration by Sandbox Studio, Chicago with Corinne Mucha

    Physicists and geologists are forming a new partnership to study particles from inside the planet.

    The Earth is like a hybrid car.

    Deep under its surface, it has two major fuel tanks. One is powered by dissipating primordial energy left over from the planet’s formation. The other is powered by the heat that comes from radioactive decay.

    We have only a shaky understanding of these heat sources, says William McDonough, a geologist at the University of Maryland. “We don’t have a fuel gauge on either one of them. So we’re trying to unravel that.”

    One way to do it is to study geoneutrinos, a byproduct of the process that burns Earth’s fuel. Neutrinos rarely interact with other matter, so these particles can travel straight from within the Earth to its surface and beyond.

    Geoneutrinos hold clues as to how much radioactive material the Earth contains. Knowing that could lead to insights about how our planet formed and its modern-day dynamics. In addition, the heat from radioactive decay plays a key role in driving plate tectonics.

    The tectonic plates of the world were mapped in 1996, USGS.
    The tectonic plates of the world were mapped in 1996, USGS

    Understanding the composition of the planet and the motion of the plates could help geologists model seismic activity.

    To effectively study geoneutrinos, scientists need knowledge both of elementary particles and of the Earth itself. The problem, McDonough says, is that very few geologists understand particle physics, and very few particle physicists understand geology. That’s why physicists and geologists have begun coming together to build an interdisciplinary community.

    “There’s really a need for a beyond-superficial understanding of the physics for the geologists and likewise a nonsuperficial understanding of the Earth by the physicists,” McDonough says, “and the more that we talk to each other, the better off we are.”

    There are hurdles to overcome in order to get to that conversation, says Livia Ludhova, a neutrino physicist and geologist affiliated with Forschungzentrum Jülich and RWTH Aachen University in Germany. “I think the biggest challenge is to make a common dictionary and common understanding—to get a common language. At the basic level, there are questions on each side which can appear very naïve.”

    In July, McDonough and Gianpaolo Bellini, emeritus scientist of the Italian National Institute of Nuclear Physics and retired physics professor at the University of Milan, led a summer institute for geology and physics graduate students to bridge the divide.

    “In general, geology is more descriptive,” Bellini says. “Physics is more structured.”

    This can be especially troublesome when it comes to numerical results, since most geologists are not used to working with the defined errors that are so important in particle physics.

    At the summer institute, students began with a sort of remedial “preschool,” in which geologists were taught how to interpret physical uncertainty and the basics of elementary particles and physicists were taught about Earth’s interior. Once they gained basic knowledge of one another’s fields, the scientists could begin to work together.

    This is far from the first interdisciplinary community within science or even particle physics. Ludhova likens it to the field of radiology: There is one expert to take an X-ray and another to determine a plan of action once all the information is clear. Similarly, particle physicists know how to take the necessary measurements, and geologists know what kinds of questions they could answer about our planet.

    Right now, only two major experiments are looking for geoneutrinos: KamLAND at the Kamioka Observatory in Japan and Borexino at the Gran Sasso National Laboratory in Italy. Between the two of them, these observatories detect fewer than 20 geoneutrinos a year.

    KamLAND
    KamLAND at the Kamioka Observatory in Japan

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

    Between the two of them, these observatories detect fewer than 20 geoneutrinos a year.

    Because of the limited results, geoneutrino physics is by necessity a small discipline: According to McDonough, there are only about 25 active neutrino researchers with a deep knowledge of both geology and physics.

    Over the next decade, though, several more neutrino detectors are anticipated, some of which will be much larger than KamLAND or Borexino. The Jiangmen Underground Neutrino Observatory (JUNO) in China, for example, should be ready in 2020.

    JUNO Neutrino detector China
    JUNO Neutrino detector China

    Whereas Borexino’s detector is made up of 300 tons of active material, and KamLAND’s contains 1000, JUNO’s will have 20,000 tons.

    The influx of data over the next decade will allow the community to emerge into the larger scientific scene, Bellini says. “There are some people who say ‘now this is a new era of science’—I think that is exaggerated. But I do think that we have opened a new chapter of science in which we use the methods of particle physics to study the Earth.”

    See the full article here .

    Please help promote STEM in your local schools.

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 1:08 pm on October 7, 2016 Permalink | Reply
    Tags: Neutrinos, , ,   

    From Symmetry: “Hunting the nearly un-huntable” 

    Symmetry Mag
    Symmetry

    10/07/16
    Andre Salles

    1
    Artwork by Sandbox Studio, Chicago with Corinne Mucha

    The MINOS and Daya Bay experiments weigh in on the search for sterile neutrinos.

    In the 1990s, the Liquid Scintillator Neutrino Detector (LSND) experiment at Los Alamos National Laboratory saw intriguing hints of an undiscovered type of particle, one that (as of yet) cannot be detected. In 2007, the MiniBooNE experiment at the US Department of Energy’s Fermi National Accelerator Laboratory followed up and found a similar anomaly.

    LSND Experiment University of California
    LSND Experiment University of California

    FNAL/MiniBooNE
    FNAL/MiniBooNE

    Today scientists on two more neutrino experiments—the MINOS experiment at Fermilab and the Daya Bay experiment in China—entered the discussion, presenting results that limit the places where these particles, called sterile neutrinos, might be hiding.

    FNAL/MINOS
    FNAL/MINOS

    Daya Bay, approximately 52 kilometers northeast of Hong Kong and 45 kilometers east of Shenzhen, China
    “Daya Bay, approximately 52 kilometers northeast of Hong Kong and 45 kilometers east of Shenzhen, China

    “This combined result was a two-year effort between our collaborations,” says MINOS scientist Justin Evans of the University of Manchester. “Together we’ve set what we believe is a very strong limit on a very intriguing possibility.”

    In three separate papers—two published individually by MINOS and Daya Bay and one jointly, all in Physical Review Letters—scientists on the two experiments detail the results of their hunt for sterile neutrinos.

    Both experiments are designed to see evidence of neutrinos changing, or oscillating, from one type to another. Scientists have so far observed three types of neutrinos, and have detected them changing between those three types, a discovery that was awarded the 2015 Nobel Prize in physics.

    What the LSND and MiniBooNE experiments saw—an excess of electron neutrino-like signals—could be explained by a two-step change: muon neutrinos morphing into sterile neutrinos, then into electron neutrinos. MINOS and Daya Bay measured the rate of these steps using different techniques.

    MINOS, which is fed by Fermilab’s neutrino beam—the most powerful in the world—looks for the disappearance of muon neutrinos. MINOS can also calculate how often muon neutrinos should transform into the other two known types and can infer from that how often they could be changing into a fourth type that can’t be observed by the MINOS detector.

    Daya Bay performed a similar observation with electron anti-neutrinos (assumed, for the purposes of this study, to behave in the same way as electron neutrinos).

    The combination of the two experiments’ data (and calculations based thereon) cannot account for the apparent excess of neutrino-like signals observed by LSND. That along with a reanalysis of results from Bugey, an older experiment in France, leaves only a very small region where sterile neutrinos related to the LSND anomaly could be hiding, according to scientists on both projects.

    “There’s a very small parameter space left that the LSND signal could correspond to,” says Alex Sousa of the University of Cincinnati, one of the MINOS scientists who worked on this result. “We can’t say that these light sterile neutrinos don’t exist, but the space where we might find them oscillating into the neutrinos we know is getting narrower.”

    Both Daya Bay and MINOS’ successor experiment, MINOS+, have already taken more data than was used in the analysis here. MINOS+ has completely analyzed only half of its collected data to date, and Daya Bay plans to quadruple its current data set. The potential reach of the final joint effort, says Kam-Biu Luk, co-spokesperson of the Daya Bay experiment, “could be pretty definitive.”

    The IceCube collaboration, which measures atmospheric neutrinos with a detector deep under the Antarctic ice, recently conducted a similar search for sterile neutrinos and also came up empty.

    U Wisconsin ICECUBE neutrino detector at the South Pole
    IceCube neutrino detector interior
    U Wisconsin ICECUBE neutrino detector at the South Pole

    All of this might seem like bad news for fans of sterile neutrinos, but according to theorist André de Gouvea of Northwestern University, the hypothesis is still alive.

    Sterile neutrinos are “still the best new physics explanation for the LSND anomaly that we can probe, even though that explanation doesn’t work very well,” de Gouvea says. “The important thing to remember is that these results from MINOS, Daya Bay, Ice Cube and others don’t rule out the concept of sterile neutrinos, as they may be found elsewhere.”

    Theorists have predicted the existence of sterile neutrinos based on anomalous results from several different experiments. The results from MINOS and Daya Bay address the sterile neutrinos predicted based on the LSND and MiniBooNE anomalies. Theorists predict other types of sterile neutrinos to explain anomalies in reactor experiments and in experiments using the chemical gallium. Much more massive types of sterile neutrinos would help explain why the neutrinos we know are so very light and how the universe came to be filled with more matter than antimatter.

    Searches for sterile neutrinos have focused on the LSND neutrino excess, de Gouvea says, because it provides a place to look. If that particular anomaly is ruled out as a key to finding these nigh-undetectable particles, then they could be hiding almost anywhere, leaving no clues. “Even if sterile neutrinos do not explain the LSND anomaly, their existence is still a logical possibility, and looking for them is always interesting,” de Gouvea says.

    Scientists around the world are preparing to search for sterile neutrinos in different ways.

    Fermilab is preparing a three-detector suite of short-baseline experiments dedicated to nailing down the cause of both the LSND anomaly and an excess of electrons seen in the MiniBooNE experiment. These liquid-argon detectors will search for the appearance of electron neutrinos, a method de Gouvea says is a more direct way of addressing the LSND anomaly. One of those detetors, MicroBooNE, is specifically chasing down the MiniBooNE excess.

    FNAL/MicrobooNE
    FNAL/MicrobooNE

    Scientists at Oak Ridge National Laboratory are preparing the Precision Oscillation and Spectrum Experiment (PROSPECT), which will search for sterile neutrinos generated by a nuclear reactor.

    Yale PROSPECT Neutrino experiment
    Yale PROSPECT Neutrino experiment

    CERN’s SHiP experiment, which stands for Search for Hidden Particles, is expected to look for sterile neutrinos with much higher predicted masses.

    CERN SHiP Experiment
    CERN SHiP Experiment

    Obtaining a definitive answer to the sterile neutrino question is important, Evans says, because the existence (or non-existence) of these particles might impact how scientists interpret the data collected in other neutrino experiments, including Japan’s T2K, the United States’ NOvA, the forthcoming DUNE, and other future projects.

    T2K map
    T2K map

    FNAL/NOvA experiment
    FNAL/NOvA experiment

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

    DUNE in particular will be able to look for sterile neutrinos across a broad spectrum, and evidence of a fourth kind of neutrino would enhance its already rich scientific program.

    “It’s absolutely vital that we get this question resolved,” Evans says. “Whichever way it goes, it will be a crucial part of neutrino experiments in the future.”

    See the full article here .

    Please help promote STEM in your local schools.

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 1:22 pm on September 29, 2016 Permalink | Reply
    Tags: , , , , Neutrinos, , Revealing the unseen Universe   

    From Nature: “Revealing the unseen Universe” 

    Nature Mag
    Nature

    28 September 2016
    Mark Zastrow

    Astronomy is entering an era in which gravitational waves and neutrinos will be used to complement existing techniques and to uncover the hidden features of our Universe.

    Gravitational waves

    When two black holes or neutron stars in a binary system spiral towards each other, their massive size causes ripples in space-time known as gravitational waves.

    Gravitational waves. Credit: MPI for Gravitational Physics/W.Benger-Zib
    MPI for Gravitational Physics/W.Benger-Zib

    The strength of these waves increases as the black holes revolve faster, spiralling towards each other until they merge and there is a fall off in the signal (ringdown).

    Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project
    Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project

    The Universe seems to be awash with these cataclysmic collisions, which astronomers expect to tell them how many black holes and neutron stars there are.

    2
    Illustration by Lucy Reading-Ikkanda

    How to detect gravitational waves

    In the Laser Interferometer Gravitational-Wave Observatory (LIGO), which detected gravitational waves for the first time in 2015, a laser beam is split in two, and each sent down a 4-kilometre tunnel.

    LIGO bloc new
    Caltech/MIT Advanced aLigo Hanford, WA, USA installation
    “Caltech/MIT Advanced aLigo Hanford, WA, USA installation
    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA
    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA

    The beams are reflected back and forth by mirrors at the end of each tunnel, before being recombined at a detector [1].

    3
    Illustration by Lucy Reading-Ikkanda

    Normal operations

    4
    Illustration by Lucy Reading-Ikkanda

    Effect of gravitational waves

    The waves warp the region of space-time that the tunnels sit in so that the beams seem to have travelled different distances when they merge. The difference is very small — about the width of an atomic nucleus for the first detection.

    5
    Illustration by Lucy Reading-Ikkanda

    Global network of detectors

    There are three operational gravitational wave detectors around the world: two LIGO arrays and Germany’s smaller GEO600 facility. Kamioka Gravitational Wave Detector (KAGRA) and Virgo are due to come online in 2018 and 2016, respectively, and a third LIGO detector in India is planned. Combining data from multiple detectors will allow scientists to locate the origin of the waves much more precisely. The laser arms of proposed space-based observatories, such as Europe’s eLISA and China’s Taiji and TianQin, would be much longer. They could detect gravitational waves at lower frequencies and reveal events from weaker sources than can be felt on Earth [2].

    6
    Illustration by Lucy Reading-Ikkanda

    High-energy neutrinos

    Particles known as neutrinos flood the Universe and are so small that they can zip straight through most matter, making them the ideal cosmic messenger. By studying neutrinos, scientists hope to piece together details of the events that made the particles.

    7
    llustration by Lucy Reading-Ikkanda

    IceCube neutrino observatory

    Located beneath the Amundsen–Scott South Pole Station, a US research facility, the detector of the IceCube neutrino observatory is arranged over one cubic kilometre of ice. IceCube’s sensitivity is partly due to the fact that ice in the region is one of the purest and most transparent solids on Earth [3].

    8
    Illustration by Lucy Reading-Ikkanda

    U Wisconsin ICECUBE neutrino detector at the South Pole
    IceCube neutrino detector interior
    U Wisconsin ICECUBE neutrino detector at the South Pole

    Timeline of high-energy neutrino discovery

    9
    Illustration by Lucy Reading-Ikkanda

    Sources
    1. LIGO Scientific Collaboration
    2. Nature 531, 150 (2016)
    3. IceCube/Univ. Wisconsin–Madison

    Related external links
    LIGO
    IceCube
    eLISA

    ESA/eLISA
    “ESA/eLISA

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

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    Nature is a weekly international journal publishing the finest peer-reviewed research in all fields of science and technology on the basis of its originality, importance, interdisciplinary interest, timeliness, accessibility, elegance and surprising conclusions. Nature also provides rapid, authoritative, insightful and arresting news and interpretation of topical and coming trends affecting science, scientists and the wider public.

     
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