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  • richardmitnick 10:03 am on July 24, 2017 Permalink | Reply
    Tags: , Neutrinos, , , , Where are the IceCube neutrinos coming from? (part 2)   

    From astrobites: “Where are the IceCube neutrinos coming from? (part 2)” 

    Astrobites bloc

    Astrobites

    Jul 24, 2017

    Title: Constraints on Galactic Neutrino Emission with Seven Years of IceCube Data.
    Authors: The IceCube Collaboration

    U Wisconsin ICECUBE neutrino detector at the South Pole


    Status: Submitted to The Astrophysical Journal, [open access]

    Back in 2013, the IceCube Collaboration published a paper [Science November 22nd] announcing their discovery of astrophysical neutrinos, i.e. ones that have an origin outside our Solar System (Astrobites coverage). Since this discovery, scientists have been busily working to develop theories as to the origin of these neutrinos. The original paper noted some clustering in the area of the center of our Galaxy, but it was not statistically significant. Since then, both Galactic and extragalactic origins have been proposed. Star-forming galaxies have been suggested as one possible origin, which Astrobites has covered papers arguing both for and against (here and here). Other theories involve radio galaxies, transients, and dark matter.

    In today’s paper, the IceCube Collaboration has analyzed more of their data and set limits on the percentage of the diffuse neutrino flux that can come from Galactic sources. Theoretically, some neutrinos should be created in the Galactic plane: we know that this area emits gamma rays from pion decay, and neutrinos are created in the same types of interactions that create the gamma rays.

    The collaboration used an unbinned maximum likelihood method as the main analysis technique in this paper. This is a standard technique used in astrophysics; it takes a model and finds the values of all the parameters of that model that give the best likelihood of getting the data that has been observed. (A second, separate technique was used as a cross-check). They used five different catalogs of Galactic sources expected to emit neutrinos to determine where to search. Sources included pulsar wind nebulae and supernovae interacting with molecular clouds. The upper limits on the flux from our galaxy can be seen below.

    1
    Figure 1: Upper limits on the neutrino flux from the Galaxy, assuming a three-flavor neutrino flux and a certain emission model known as the KRA-gamma model. The red limits are from this paper (with the grey showing how the limits change if other emission models are used); the blue are from ANTARES, which is another neutrino experiment. For comparison, the measured overall neutrino flux is also shown (black data points and the yellow band). The green band is from the data, but only data from the northern sky is used. IceCube is more sensitive in the Northern hemisphere. (Source: Figure 2 of the paper.)

    It turns out that, under these assumptions, Galactic contributions can’t be more than 14% of the diffuse neutrino flux. However, the authors note that there are still scenarios where the flux could originate in/near the Galaxy. This paper focused on emission in the Galactic plane, but cosmic ray interactions in a gas halo far from the plane, and/or dark matter annihilation or decay would change the emission templates that were used here. They also mention that the limits could be made stronger by doing a joint analysis with ANTARES.

    Anteres Neutrino Telescope Underwater, a large area water Cherenkov detector in the deep Mediterranean Sea, 40 km off the coast of Toulon, Fr

    Since IceCube and ANATARES are located in different hemispheres, they are most sensitive in different areas of the sky. The mystery continues…

    See the full article here .

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    What do we do?

    Astrobites is a daily astrophysical literature journal written by graduate students in astronomy. Our goal is to present one interesting paper per day in a brief format that is accessible to undergraduate students in the physical sciences who are interested in active research.
    Why read Astrobites?

    Reading a technical paper from an unfamiliar subfield is intimidating. It may not be obvious how the techniques used by the researchers really work or what role the new research plays in answering the bigger questions motivating that field, not to mention the obscure jargon! For most people, it takes years for scientific papers to become meaningful.
    Our goal is to solve this problem, one paper at a time. In 5 minutes a day reading Astrobites, you should not only learn about one interesting piece of current work, but also get a peek at the broader picture of research in a new area of astronomy.

     
  • richardmitnick 12:26 pm on July 18, 2017 Permalink | Reply
    Tags: , , Neutrinos,   

    From DUNE: “Video: The science of DUNE” 

    SURF logo
    Sanford Underground levels

    Sanford Underground Research facility

    See the full article here .

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

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

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

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

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

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

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

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

    Fermilab LBNE
    LBNE

     
  • richardmitnick 10:22 pm on July 15, 2017 Permalink | Reply
    Tags: , , , , , , , MEET SURF, Neutrinos, , , U Washington Majorana   

    Meet SURF-Sanford Underground Research Facility, South Dakota, USA 

    SURF logo
    Sanford Underground levels

    THIS POST IS DEDICATED TO CONSTANCE WALTER, Communications Director, fantastic writer, AND MATT KAPUST Creative Services Developer, master photogropher, FOR THEIR TIRELESS EFFORTS IN KEEPING US INFORMED ABOUT PROGRESS FOR SCIENCE IN SOUTH DAKOTA, USA.

    Sanford Underground Research facility

    The SURF story in pictures:

    SURF-Sanford Underground Research Facility


    SURF Above Ground

    SURF Out with the Old


    SURF An Empty Slate


    SURF Carving New Space


    SURF Shotcreting


    SURF Bolting and Wire Mesh


    SURF Outfitting Begins


    SURF circular wooden frame was built to form a concrete ring to hold the 72,000-gallon (272,549 liters) water tank that would house the LUX dark matter detector


    SURF LUX water tank was transported in pieces and welded together in the Davis Cavern


    SURF Ground Support


    SURF Dedicated to Science


    SURF Building a Ship in a Bottle


    SURF Tight Spaces


    SURF Ready for Science


    SURF Entrance Before Outfitting


    SURF Entrance After Outfitting


    SURF Common Corridior


    SURF Davis


    SURF Davis A World Class Site


    SURF Davis a Lab Site


    SURF DUNE LBNF Caverns at Sanford Lab


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


    FNAL DUNE Argon tank at SURF

    U Washington LUX Xenon experiment at SURF


    SURF Before Majorana


    U Washington Majorana Demonstrator Experiment at SURF

    This is the full article here .

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

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

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

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

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

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

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

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

    Fermilab LBNE
    LBNE

     
  • richardmitnick 1:11 pm on July 5, 2017 Permalink | Reply
    Tags: , Cosmic ray tagger, FNAL/SBND, , Neutrinos, SBND - Short-Baseline Near Detector, University of Bern   

    From FNAL: “SBND’s cosmic ray tagger begins taking data” 

    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.

    June 28, 2017
    Igor Kreslo

    1
    Members of the Short-Baseline Near Detector collaboration install the cosmic ray tagger in the SBND building. The cosmic ray tagger is made of the shiny, rectangular panels on the building floor. Photo: Reidar Hahn.

    On the morning of June 22, an important component of the Short-Baseline Near Detector (SBND) began taking data.

    The component, called the cosmic ray tagger, is the first of SBND’s subdetectors to be completed and operational.

    The SBND collaboration is constructing the Short-Baseline Near Detector piece by piece, and with the completion of the cosmic ray tagger, we’ve reached a construction and operations milestone.

    The SBND’s sought-after particle is the neutrino — a fleeting, difficult-to-capture particle. Adding to the difficulty is the fact that cosmic rays from outer space cloud the sought-after neutrino signal in the detector. The cosmic ray tagger, or CRT, is designed to identify the cosmic rays that rain down on the detector so scientists can subtract those traces from their data, revealing the neutrino signal.

    By functionality it is similar to the one installed earlier at the MicroBooNE detector, which you may have read about.

    The SBND collaboration installed and commissioned the cosmic ray tagger this month — in only two weeks. The CRT is composed of many finely grained modules capable of measuring an interaction instance to the nanosecond and to within a centimeter of its location in the CRT.

    With the newly operational cosmic ray tagger in its current configuration, SBND is currently characterizing the flux of particles called muons. These muons are produced by neutrinos from the Booster Neutrino Beamline so that scientists can measure their parameters in the SBND pit, where SBND will be built. Data taken during this characterization stage will be a great asset on the way to simulation and analysis for the whole SBND detector later on.

    The collaboration will continue to take data using the beam from the Booster Neutrino Beamline, as well as from cosmic rays, until the accelerator shutdown in July. When the accelerator complex restarts in October, we will restart data-taking using the CRT.

    We are grateful to collaborators at the University of Bern who designed and produced the CRT modules. And the swift installation and commissioning was possible thanks only to the tremendous dedication and commitment of many colleagues from the SBND collaboration as well as great support from Fermilab technical personnel.

    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 12:47 pm on July 5, 2017 Permalink | Reply
    Tags: , , Neutrinos,   

    From FNAL: “Contract to design rock conveyor for neutrino experiment awarded” 

    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.

    July 5, 2017
    Leah Hesla

    If in a few years you happen to travel down Highway 85 in the Black Hills near Lead, South Dakota, you will find yourself passing beneath a new, narrow beam-like structure stretching across the road overhead.

    You’ll be crossing under part of a conveyor system that will be used to transport rock from nearly a mile underground at the former Homestake gold mine — now the Sanford Underground Research Facility — to an enormous open pit on the surface as underground space is carved out to house a giant particle detector.

    1
    The North Alabama Fabricating Company has been contracted to design and fabricate a rock conveyor to help remove rock from the former Homestake Mine. This effort is to make way for a giant particle detector for the international Deep Underground Neutrino Experiment. The detector will be situated nearly a mile underground. Image: Sanford Lab

    Scientists from the international Deep Underground Neutrino Experiment (DUNE), an experiment hosted by the U.S. Department of Energy’s Fermi National Accelerator Laboratory, will build and use the mammoth detector to study particles called neutrinos. Understanding these particles is expected to lead to a deeper knowledge of how our universe is put together.

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


    FNAL DUNE Argon tank at SURF


    Surf-Dune/LBNF Caverns at Sanford



    SURF building in Lead SD USA

    On June 28, Fermi Research Alliance LLC, which operates Fermilab, signed a contract with North Alabama Fabricating Company to design and fabricate the pipe conveyor to be installed at Sanford Lab. The contract supports the excavation for the Long-Baseline Neutrino Facility (LBNF), the facility that will house and support DUNE.

    “The fabrication and installation of the pipe conveyor will be a major step toward LBNF excavation,” said Mike Headley, executive director of the South Dakota Science and Technology Authority, or SDSTA, which owns and operates Sanford Lab. “It’s an exciting milestone, and the SDSTA is proud to support the LBNF team on this project.”

    Fermilab and Sanford Lab staff expect conveyor installation to begin in mid-2018 and continue for six months. Rock removal is expected to take about three years once the conveyor begins operating.

    2
    The rock conveyor will transport rock excavated from the former Homestake Mine to a nearby open cut. Image: Sanford Lab.

    “The conveyor will transport 875,000 tons of rock — approximately equal to the mass of eight Nimitz class aircraft carriers,” said retired U.S. Navy admiral Chris Mossey, who is now the LBNF project director at Fermilab.

    Like a giant futuristic supermarket checkout lane, the rock conveyor will move rock over a stretch of 3,700 feet while containing dust and debris.

    The conveyor path will take advantage of a long, existing tunnel carved out during Homestake’s gold mining days in the 1930s. The conveyor will start 175 feet underground, make its way to the surface, and continue high above ground until it arrives at the pit, called an open cut, which is roughly two miles wide and 1,200 feet deep. In fact, miners used a similar machine in the 1980s to transport rock away from the open cut as they looked for gold.

    3
    This is a conceptual illustration of the aboveground portion of the rock conveyor. Image: Sanford Lab.

    LBNF project members have kept in close contact with the city of Lead and its residents regarding rock-handling options, as well as with the State Historic Preservation Office to ensure that cultural aspects of the site are understood and respected. The communication will continue as the design evolves.

    “The design team has worked hard to come up with the right system,” said Fermilab’s Elaine McCluskey, LBNF project manager.

    Excavation for the DUNE detector caverns is expected to be complete in early 2022.

    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 7:02 am on July 1, 2017 Permalink | Reply
    Tags: , , , , Neutrinos, , Week 25 at the Pole   

    From U Wisconsin IceCube: “Week 25 at the Pole” 

    icecube
    U Wisconsin IceCube South Pole Neutrino Observatory

    30 Jun 2017
    Jean DeMerit

    1
    Martin Wolf, IceCube/NSF

    Last week the IceCube detector had almost perfect uptime. They survived a mid-week 90-second power outage with no interruption to data taking, but then a power supply failure just at the end of the week ruined the perfect performance. The third round in the poker tournament, however, didn’t ruin winterover Martin’s standing—he’s still in the lead going into the finals. It was Martin’s birthday last week, so the galley staff made a nice cake to celebrate. The aurora in the bottom image seems to be ushering in the upcoming 4th of July celebrations.

    2
    James Casey, IceCube/NSF

    3
    James Casey, IceCube/NSF

    4
    James Casey, IceCube/NSF

    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 3:33 pm on June 27, 2017 Permalink | Reply
    Tags: , , , Cassiopeia A supernova remnant, , MPA, Neutrinos, ,   

    From Max Planck Institute for Astrophysics, Garching: “Neutrinos as drivers of supernovae” 

    Max Planck Institute for Astrophysics, Garching

    June 26, 2017
    Dr. Hans-Thomas Janka
    Max Planck Institute for Astrophysics, Garching
    Phone:+49 89 30000-2228
    Fax:+49 89 30000-2235
    thj@mpa-garching.mpg.de

    Dr. Hannelore Hämmerle
    Max Planck Institute for Astrophysics, Garching
    Phone:+49 89 30000-3980
    hhaemmerle@mpa-garching.mpg.de

    1
    Time evolution of the radioactive 56Ni in the ejecta of a 3D simulation of a neutrino-driven supernova explosion. The images show the non-spherical distribution from shortly after the onset of the explosion (3.25 seconds) until a late time (6236 seconds) when the final asymmetry is determined. The colours represent radial velocities according to the scales given for each panel. © MPA

    Radioactive elements in gaseous supernova remnant Cassiopeia A provide glimpses into the explosion of massive stars.

    2
    Cassiopeia A. NASA/CXC/SAO

    NASA/Chandra Telescope

    Stars exploding as supernovae are the main sources of heavy chemical elements in the Universe. In these star explosions, radioactive atomic nuclei are synthesized in the hot, innermost regions during the explosion and can thus provide insights into the unobservable physical processes that initiate the blast. Using elaborate computer simulations, a team of researchers from the Max Planck Institute for Astrophysics (MPA) and the research institute RIKEN in Japan were able to explain the recently measured spatial distributions of radioactive titanium and nickel in Cassiopeia A, a roughly 340 year old gaseous remnant of a nearby supernova.

    RIKEN campus

    The computer models yield strong support for the theoretical idea that such stellar death events can be initiated and powered by neutrinos escaping from the neutron star left behind at the origin of the explosion.

    Massive stars end their lives in gigantic explosions, so-called supernovae. Within millions of years of stable evolution, these stars have built up a central core composed of mostly iron. When the core reaches about 1.5 times the mass of the Sun, it collapses under the influence of its own gravity and forms a neutron star. Enormous amounts of energy are released in this catastrophic event, mostly by the emission of neutrinos. These nearly massless elementary particles are abundantly produced in the interior of the new-born neutron star, where the density is higher than in atomic nuclei and the temperature can reach 500 billion degrees Kelvin.

    The physical processes that trigger and drive the explosion have been an unsolved puzzle for more than 50 years. One of the theoretical mechanisms proposed invokes the neutrinos, because they carry away more than hundred times the energy needed for a typical supernova. Leaking out from the hot interior of the neutron star, a small fraction of the neutrinos are absorbed in the surrounding gas. This heating causes violent motions of the gas, similar to those in a pot of boiling water on a stove. When the bubbling of the gas becomes sufficiently powerful, the supernova explosion sets in as if the lid of the pot were blown off. The outer layers of the dying star are expelled into circumstellar space, and with them all the chemical elements that the star has assembled by nuclear burning during its life. But also new elements are created in the hot ejecta of the explosion, among them radioactive species such as 44Ti (titanium with 22 protons and 22 neutrons in its atomic nuclei) and 56Ni (28/28 neutrons/protons), which decay to stable calcium and iron, respectively. The thus released radioactive energy makes a supernova shine bright for years.

    3
    Observed distribution of 44Ti (blue) and iron (white, red) in Cassiopeia A. The visible iron is mostly the radioactive decay product of 56Ni. The yellow cross marks the geometrical centre of the explosion, the white cross and the arrow indicate the current location and the direction of motion of the neutron star. © Macmillan Publishers Ltd: Nature; from Grefenstette et al., Nature 506, 339 (2014); Fe distribution courtesy of U.~Hwang.)

    Because of the wild boiling of the neutrino-heated gas, the blast wave starts out non-spherically and imprints a large-scale asymmetry on the ejected stellar matter and the supernova as a whole, in agreement with the observation of clumpiness and asymmetries in many supernovae and their gaseous remnants. The initial asymmetry of the explosion has two immediate consequences. On the one hand, the neutron star receives a recoil momentum opposite to the direction of the stronger explosion, where the supernova gas is expelled with more violence. This effect is similar to the kick a rowing boat receives when a passenger jumps off. On the other hand, the production of heavy elements from silicon to iron, in particular also of 44Ti and 56Ni, is more efficient in directions where the explosion is stronger and where more matter is heated to high temperatures. “We have predicted both effects some years ago by our three-dimensional (3D) simulations of neutrino-driven supernova explosions”, says Annop Wongwathanarat, researcher at RIKEN and lead author of the corresponding publication of 2013, at which time he worked at MPA in collaboration with his co-authors H.-Thomas Janka and Ewald Müller. “The asymmetry of the radioactive ejecta is more pronounced the larger the neutron star kick is”, he adds. Since the radioactive atomic nuclei are synthesized in the innermost regions of the supernova, in the very close vicinity of the neutron star, their spatial distribution reflects explosion asymmetries most directly.

    New observations of Cassiopeia A (Cas A), the gaseous remnant of a supernova whose light reached the Earth around the year 1680, could meanwhile confirm this theoretical prediction. Because of its young age and relative proximity at a distance of just 11,000 light years, Cas A offers two great advantages for the measurements. First, the radioactive decay of 44Ti is still an efficient energy source, and the presence of this atomic nucleus can therefore be mapped in 3D with high precision in the whole remnant by detecting the high-energy X-ray radiation from the radioactive decays. Second, also the velocity of the neutron star is known with its magnitude and its direction on the plane of the sky.

    4
    Observable radioactive nickel (56Ni, green) and titanium (44Ti, blue) as predicted by the 3D simulation of a neutrino-driven supernova explosion shown in Fig. 1. The orientation is optimized for closest possible similarity to the Cas A image of Fig. 2a. The neutron star is marked by a white cross and shifted away from the centre of the explosion (red plus symbol) because of its kick velocity. The neutron star motion points away from the hemisphere that contains most of the ejected 44Ti. Iron of its kick velocity. The neutron star motion points away from the hemisphere that contains most of the ejected 44Ti. Iron (the decay product of Ni56) can be observed only in an outer, hot shell of Cas A. © MPA

    Since the neutron star propagates with an estimated speed of at least 350 kilometres per second, the asymmetry in the spatial distribution of the radioactive elements is expected to be very pronounced. Exactly this is seen in the observations . While the compact remnant speeds toward the lower hemisphere, the biggest and brightest clumps with most of the 44Ti are found in the upper half of the gas remnant. The computer simulation, viewed from a suitably chosen direction, exhibits a striking similarity to the observational image. But not only the spatial distributions of titanium and iron resemble those in Cas A (for a 3D visualization, see Fig. 3 in comparison with the 3D imaging of Cas A available at the weblink http://3d.si.edu/explorer?modelid=45). Also the total amounts of these elements, their expansion velocities, and the velocity of the neutron star are in amazing agreement with those of Cas A. “This ability to reproduce basic properties of the observations impressively confirms that Cas A may be the remnant of a neutrino-driven supernova with its violent gas motions around the nascent neutron star”, concludes H.-Thomas Janka.

    But more work is needed to finally prove that the explosions of massive stars are powered by energy input from neutrinos. “Cas A is an object of so much interest and importance that we must also understand the spatial distributions of other chemical species such as silicon, argon, neon, and oxygen”, remarks Ewald Müller, pointing to the beautiful multi-component morphology of Cas A revealed by 3D imaging (see http://3d.si.edu/explorer?modelid=45). One example is also not enough for making a fully convincing case. Therefore the team has joined a bigger collaboration to test the theoretical predictions for neutrino-driven explosions by a close analysis of a larger sample of young supernova remnants. Step by step the researchers thus hope to collect evidence that is able to settle the long-standing problem of the supernova mechanism.

    See the full article here .

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  • richardmitnick 3:09 pm on June 24, 2017 Permalink | Reply
    Tags: , CERN ProtoDUNE, , , Neutrinos, ,   

    From Symmetry: “World’s biggest neutrino experiment moves one step closer” 

    Symmetry Mag

    Symmetry

    06/23/17
    Lauren Biron

    1
    Photo by Maximilien Brice, CERN

    The startup of a 25-ton test detector at CERN advances technology for the Deep Underground Neutrino Experiment.

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


    FNAL DUNE Argon tank at SURF


    Surf-Dune/LBNF Caverns at Sanford



    SURF building in Lead SD USA

    In a lab at CERN sits a very important box. It covers about three parking spaces and is more than a story tall. Sitting inside is a metal device that tracks energetic cosmic particles.

    CERN Proto DUNE Maximillian Brice

    This is a prototype detector, a stepping-stone on the way to the future Deep Underground Neutrino Experiment (DUNE). On June 21, it recorded its first particle tracks.

    So begins the largest ever test of an extremely precise method for measuring elusive particles called neutrinos, which may hold the key to why our universe looks the way it does and how it came into being.

    A two-phase detector

    The prototype detector is named WA105 3x1x1 (its dimensions in meters) and holds five active tons—3000 liters—of liquid argon. Argon is well suited to interacting with neutrinos then transmitting the subsequent light and electrons for collection. Previous liquid argon neutrino detectors, such as ICARUS and MicroBooNE, detected signals from neutrinos using wires in the liquid argon. But crucially, this new test detector also holds a small amount of gaseous argon, earning it the special status of a two-phase detector.

    INFN Gran Sasso ICARUS, since moved to FNAL

    FNAL/ICARUS

    FNAL/MicrobooNE

    As particles pass through the detector, they interact with the argon atoms inside. Electrons are stripped off of atoms and drift through the liquid toward an “extraction grid,” which kicks them into the gas. There, large electron multipliers create a cascade of electrons, leading to a stronger signal that scientists can use to reconstruct the particle track in 3D. Previous tests of this method were conducted in small detectors using about 250 active liters of liquid argon.

    “This is the first time anyone will demonstrate this technology at this scale,” says Sebastien Murphy, who led the construction of the detector at CERN.

    The 3x1x1 test detector represents a big jump in size compared to previous experiments, but it’s small compared to the end goal of DUNE, which will hold 40,000 active tons of liquid argon. Scientists say they will take what they learn and apply it (and some of the actual electronic components) to next-generation single- and dual-phase prototypes, called ProtoDUNE.

    The technology used for both types of detectors is a time projection chamber, or TPC. DUNE will stack many large modules snugly together like LEGO blocks to create enormous DUNE detectors, which will catch neutrinos a mile underground at Sanford Underground Research Facility in South Dakota. Overall development for liquid argon TPCs has been going on for close to 40 years, and research and development for the dual-phase for more than a decade. The idea for this particular dual-phase test detector came in 2013.

    “The main goal [with WA105 3x1x1] is to demonstrate that we can amplify charges in liquid argon detectors on the same large scale as we do in standard gaseous TPCs,” Murphy says.

    By studying neutrinos and antineutrinos that travel 800 miles through the Earth from the US Department of Energy’s Fermi National Accelerator Laboratory [FNAL] to the DUNE detectors, scientists aim to discover differences in the behavior of matter and antimatter. This could point the way toward explaining the abundance of matter over antimatter in the universe. The supersensitive detectors will also be able to capture neutrinos from exploding stars (supernovae), unveiling the formation of neutron stars and black holes. In addition, they allow scientists to hunt for a rare phenomenon called proton decay.

    “All the R&D we did for so many years and now want to do with ProtoDUNE is the homework we have to do,” says André Rubbia, the spokesperson for the WA105 3x1x1 experiment and former co-spokesperson for DUNE. “Ultimately, we are all extremely excited by the discovery potential of DUNE itself.”

    2
    One of the first tracks in the prototype detector, caused by a cosmic ray. André Rubbia

    Testing, testing, 3-1-1, check, check

    Making sure a dual-phase detector and its electronics work at cryogenic temperatures of minus 184 degrees Celsius (minus 300 degrees Fahrenheit) on a large scale is the primary duty of the prototype detector—but certainly not its only one. The membrane that surrounds the liquid argon and keeps it from spilling out will also undergo a rigorous test. Special cryogenic cameras look for any hot spots where the liquid argon is predisposed to boiling away and might cause voltage breakdowns near electronics.

    After many months of hard work, the cryogenic team and those working on the CERN neutrino platform have already successfully corrected issues with the cryostat, resulting in a stable level of incredibly pure liquid argon. The liquid argon has to be pristine and its level just below the large electron multipliers so that the electrons from the liquid will make it into the gaseous argon.

    “Adding components to a detector is never trivial, because you’re adding impurities such as water molecules and even dust,” says Laura Manenti, a research associate at the University College London in the UK. “That is why the liquid argon in the 311—and soon to come ProtoDUNEs—has to be recirculated and purified constantly.”

    While ultimately the full-scale DUNE detectors will sit in the most intense neutrino beam in the world, scientists are testing the WA105 3x1x1 components using muons from cosmic rays, high-energy particles arriving from space. These efforts are supported by many groups, including the Department of Energy’s Office of Science.

    The plan is now to run the experiment, gather as much data as possible, and then move on to even bigger territory.

    “The prospect of starting DUNE is very exciting, and we have to deliver the best possible detector,” Rubbia says. “One step at a time, we’re climbing a large mountain. We’re not at the top of Everest yet, but we’re reaching the first chalet.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 12:37 pm on June 6, 2017 Permalink | Reply
    Tags: , , , , , Neutrinos   

    From FNAL: “Follow the fantastic voyage of the ICARUS neutrino detector” 

    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.

    June 6, 2017

    Andre Salles
    Fermilab Office of Communication
    asalles@fnal.gov
    630-840-6733

    CERN Press Office
    press.office@cern.ch
    +41227673432
    +41227672141

    Eleonora Cossi
    INFN
    eleonora.cossi@presid.infn.it,
    +39-06-686-8162

    The world’s largest particle hunter of its kind will travel across the ocean from CERN to Fermilab this summer to become an integral part of neutrino research in the United States.

    It’s lived in two different countries, and it’s about to make its way to a third. It’s the largest machine of its kind, designed to find extremely elusive particles and tell us more about them. Its pioneering technology is the blueprint for some of the most advanced science experiments in the world. And this summer, it will travel across the Atlantic Ocean to its new home (and its new mission) at the U.S. Department of Energy’s Fermi National Accelerator Laboratory.

    2
    The ICARUS detector, seen here in a cleanroom at CERN, is being prepared for its voyage to Fermilab. Photo: CERN

    It’s called ICARUS, and you can follow its journey over land and sea with the help of an interactive map on Fermilab’s website.

    The ICARUS detector measures 18 meters (60 feet) long and weighs 120 tons. It began its scientific life under a mountain at the Italian National Institute for Nuclear Physics’ (INFN) Gran Sasso National Laboratory in 2010, recording data from a beam of particles called neutrinos sent by CERN, Europe’s premier particle physics laboratory. The detector was shipped to CERN in 2014, where it has been upgraded and refurbished in preparation for its overseas trek.

    INFN Gran Sasso ICARUS, moving to FNAL

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

    When it arrives at Fermilab, the massive machine will take its place as part of a suite of three detectors dedicated to searching for a new type of neutrino beyond the three that have been found. Discovering this so-called “sterile” neutrino, should it exist, would rewrite scientists’ picture of the universe and the particles that make it up.

    “Nailing down the question of whether sterile neutrinos exist or not is an important scientific goal, and ICARUS will help us achieve that,” said Fermilab Director Nigel Lockyer. “But it’s also a significant step in Fermilab’s plan to host a truly international neutrino facility, with the help of our partners around the world.”

    First, however, the detector has to get there. Next week it will begin its journey from CERN in Geneva, Switzerland, to a port in Antwerp, Belgium. From there the detector, separated into two identical pieces, will travel on a ship to Burns Harbor, Indiana, in the United States, and from there will be driven by truck to Fermilab, one piece at a time. The full trip is expected to take roughly six weeks.

    An interactive map on Fermilab’s website (IcarusTrip.fnal.gov) will track the voyage of the ICARUS detector, and Fermilab, CERN and INFN social media channels will document the trip using the hashtag #IcarusTrip. The detector itself will sport a distinctive banner, and members of the public are encouraged to snap photos of it and post them on social media.

    3
    The ICARUS neutrino detector prepares for its trip to Fermilab. Follow #IcarusTrip online! Photo: CERN

    Once the ICARUS detector is delivered to Fermilab, it will be installed in a recently completed building and filled with 760 tons of pure liquid argon to start the search for sterile neutrinos.

    The ICARUS experiment is a prime example of the international nature of particle physics and the mutually beneficial cooperation that exists between the world’s physics laboratories. The detector uses liquid-argon time projection technology – essentially a method of taking a 3-D snapshot of the particles produced when a neutrino interacts with an argon atom – which was developed by the ICARUS collaboration and now is the technology of choice for the international Deep Underground Neutrino Experiment (DUNE), which will be hosted by Fermilab.

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


    FNAL DUNE Argon tank at SURF


    Surf-Dune/LBNF Caverns at Sanford



    SURF building in Lead SD USA

    “More than 25 years ago, Nobel Prize winner Carlo Rubbia started a visionary effort with the help and resources of INFN to make use of liquid argon as a particle detector, with the visual power of a bubble chamber but with the speed and efficiency of an electronic detector,” said Fernando Ferroni, president of INFN. “A long series of steps demonstrated the power of this technology that has been chosen for the gigantic future experiment DUNE in the U.S., scaling up the 760 tons of argon for ICARUS to 70,000 tons for DUNE. In the meantime, ICARUS will be at the core of an experiment at Fermilab looking for the possible existence of a new type of neutrino. Long life to ICARUS!”

    CERN’s contribution to ICARUS, bringing the detector in line with the latest technology, expands the renowned European laboratory’s participation in Fermilab’s neutrino program.

    It’s the first such program CERN has contributed to in the United States. Fermilab is the hub of U.S. participation in the CMS experiment on CERN’s Large Hadron Collider, and the partnership between the laboratories has never been stronger.

    CERN CMS Higgs Event


    CERN/CMS

    LHC

    CERN/LHC Map

    CERN LHC Tunnel

    CERN LHC particles

    ICARUS will be the largest of three liquid-argon neutrino detectors at Fermilab seeking sterile neutrinos. The smallest, MicroBooNE, is active and has been taking data for more than a year, while the third, the Short-Baseline Neutrino Detector, is under construction.

    FNAL/MicrobooNE

    FNAL Short-Baseline Near Detector

    The three detectors should all be operational by 2019, and the three collaborations include scientists from 45 institutions in six countries.

    Knowledge gained by operating the suite of three detectors will be important in the development of the DUNE experiment, which will be the largest neutrino experiment ever constructed. The international Long-Baseline Neutrino Facility (LBNF) will deliver an intense beam of neutrinos to DUNE, sending the particles 800 miles through Earth from Fermilab to the large, mile-deep detector at the Sanford Underground Research Facility in South Dakota. DUNE will enable a new era of precision neutrino science and may revolutionize our understanding of these particles and their role in the universe.

    Research and development on the experiment is under way, with prototype DUNE detectors under construction at CERN, and construction on LBNF is set to begin in South Dakota this year.

    CERN Proto DUNE Maximillian Brice

    A study by Anderson Economic Group, LLC, commissioned by Fermi Research Alliance LLC, which manages the laboratory on behalf of DOE, predicts significant positive impact from the project on economic output and jobs in South Dakota and elsewhere.

    This research is supported by the DOE Office of Science, CERN and INFN, in partnership with institutions around the world.

    Follow the overseas journey of the ICARUS detector at IcarusTrip.fnal.gov. Follow the social media campaign on Facebook and Twitter using the hashtag #IcarusTrip.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    FNAL Icon
    Fermilab Campus

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

     
  • richardmitnick 7:56 pm on June 2, 2017 Permalink | Reply
    Tags: , , Homestake Mine in South Dakota, Neutrinos, Ray Davis,   

    From FNAL: “Neutrinos: the ghost particles” 

    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.

    June 2, 2017
    Mike Albrow

    1
    Scientist Ray Davis went hunting for neutrinos using a detector in the Homestake Mine in South Dakota. Photo: DOE

    Imagine: It is 1960 and you (or more likely your dad) meet a young man in a pub. He tells you his name is Ray, and you think he must be mad. He says he wants to go down a gold mine a mile underground to try to see inside the sun in the middle of the night. Or day, it doesn’t matter, because he is not using light but “invisible rays,” or particles, that go right through Earth like ghosts. He is a scientist, Ray Davis Jr., and is not mad. Forty years later he wins the Nobel Prize. The particles are called neutrinos, Italian for “little neutral ones”.

    This story starts in Victorian times, with a huge puzzle. Charles Darwin had convinced biologists that all life has been evolving from simple forms for hundreds of millions of years. But, at the rate the sun is shining, without some unknown fuel it would burn out in less than 20 million years.

    By the 1920s we had an answer. Einstein had shown that matter can be converted into energy. Nuclear reactions like those in a hydrogen bomb could be the mystery source. But as often happens in science, getting an answer leads to more mysteries.

    The energy in nuclear reactions studied in the laboratory didn’t add up. Not enough energy came out of a radioactive nucleus. But scientists know that energy cannot just disappear — it is conserved — so something must be taking it away. In 1930 Wolfgang Pauli suggested they could be tiny particles, like electrons without any electric charge, calling them neutrinos.

    In 1956 Pauli got a telegram: Neutrinos had been discovered coming out of a nuclear reactor. Then Ray Davis had that wild idea. Perhaps he could detect neutrinos coming from the nuclear reactions in the sun. Down the mine, he filled a tank with 100,000 gallons of dry-cleaning fluid.

    Eventually he extracted a few radioactive argon atoms from chlorine changed by neutrinos from the sun. But something was wrong. Theoretically he should find about two atoms per day, but he found even fewer. Was the giant nuclear reactor in the center of the sun shutting down? If so, we might not know for thousands of years. Then: serious global freezing!

    The answer is amazing, and next time I will explain. If you can’t wait, check Fermilab’s site, http://www.fnal.gov, about experiments studying these “ghost particles.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    FNAL Icon
    Fermilab Campus

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

     
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