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  • richardmitnick 5:44 pm on May 2, 2016 Permalink | Reply
    Tags: , Dark Matter, ,   

    From Surf: “Notes from the underground – LUX celebrates 300 live days” 

    SURF logo
    Sanford Underground levels

    Sanford Underground Research facility

    Monday, May 2, 2016
    Constance Walter, Communications Director, SURF

    Amid streamers, a piñata and paper unicorns, LUX researchers celebrated the 300-live-day run of their dark matter detector.

    LUX Dark matter
    LUX Dark matter
    LUX Dark matter experiment
    Lux Dark Matter 2
    Lux Dark Matter 2

    “I would describe the mood as exciting, joyous and electric,” said Mark Hanhardt, Sanford Lab support scientist. Why unicorns? For LUX researchers, they symbolize thesearch for the elusive WIMP, or weakly interacting massive particle, the leading contender in the dark matter search.

    But don’t kid yourselves, in the search for dark matter, these researchers remain focused and motivated.

    LUX consists of one third-of-a-ton of liquid xenon inside a titanium vessel.

    Researchers hope to identify the very rare occasions when a dark matter particle collides with a xenon atom inside the detector. When that happens, the xenon atom will recoil and emit a tiny flash of light, which will be detected by sensitive light detectors.

    In October 2013, after a 90-live-day run, LUX announced it was the most sensitive dark matter detector in the world. “LUX was so much larger than existing detectors that within a few weeks of starting its first run in 2013, it had surpassed all previous direct detection experiments,” said Richard Gaitskell, co-spokesperson for LUX.
    And the trend continues. In December, LUX released a reanalysis of the 2013 data, which discussed new calibration techniques that allowed for even greater sensitivity. Those techniques, which included the use of tritiated methane, krypton-83 and a neutron generator, were used in the most recent run; however, results willnot be available before the end of 2016.

    The 300-day run began in November 2014 and the detector has been in WIMP search mode or calibration mode since. But it has not been without its challenges, Gaitskell said. “During any dark matter search, we must ensure the detector is taking data in a completely stable mode in which the operating conditions are clearly understood,” he said. “This means we monitor the detector health continually and occasionally we have to react to any apparent issues that have developed.”

    At regular intervals throughout the new run, calibrations were carried out for two weeks every four months to ensure a high level of accuracy in measuring responses to backgrounds and potential dark matter signals, he added.

    After 19 months, the run officially ended today at 1 p.m. “That’s a long time to to operate a detector without a significant break,” said Simon Fiorucci, LUX science operationsmanager. “But it was critical to demonstrate our ability to do so as we prepare to run LZ for more than three years.”

    Later this year, LUX will be decommissioned to make way for a new, much larger xenon detector, known as LUX-ZEPLIN, or LZ. This second generation dark matter detector will have a 10-ton liquid xenon target and be up to 100 times more sensitive.

    LUX Xenon experiment at SURF
    LUX Xenon experiment at SURF

    “The tremendous success of LUX paved the way for LZ,” said Murdock Gilchriese, LBNL (Lawrence Berkeley National Laboratory) operations manager for LUX and LZ project director. LZ will be located inside the same 72,000-gallon water tank that currently shields LUX.

    “Sanford Lab will continue to play a global role in the search for dark matter,” said Jaret Heise, science director at Sanford Lab. “We’re looking
    forward to working with the expanded collaboration, which will include 31 institutions and about 200 scientists.”

    In the meantime, LUX researchers are continuing their work, including testing several new calibration techniques that will be used in LZ. The team has come a long way and made significant progress. “We are all proud to have made it this far,” Fiorucci said.

    See the full article here .

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

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

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

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

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

    The first two major physics experiments at the Sanford Lab are 4,850 feet underground in an area called the Davis Campus, named for the late Ray Davis. The Large Underground Xenon (LUX) experiment is housed in the same cavern excavated for Ray Davis’s experiment in the 1960s. In October 2013, after an initial run of 80 days, LUX was determined to be the most sensitive detector yet to search for dark matter—a mysterious, yet-to-be-detected substance thought to be the most prevalent matter in the universe. The Majorana Demonstrator experiment, also on the 4850 Level, is searching for a rare phenomenon called “neutrinoless double-beta decay” that could reveal whether subatomic particles called neutrinos can be their own antiparticle. Detection of neutrinoless double-beta decay could help determine why matter prevailed over antimatter. The Majorana Demonstrator experiment is adjacent to the original Davis cavern.

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

    Fermilab LBNE

  • richardmitnick 9:54 am on April 23, 2016 Permalink | Reply
    Tags: , , Dark Matter,   

    From INVERSE: “What Killed the Dinosaurs?” 



    April 22, 2016
    Neel V. Patel

    Why does life on Earth take such a beating every 35 million years.

    Since life started on Earth, there have been five mass extinction events that have led to the obliteration of 99.9 percent of all the species that have ever lived. There are a lot of theories about the causes of those events, but the most compelling and —perhaps no coincidentally — widely accepted has long been that asteroids and other objects from space slammed into the planet, triggering a massive die-off. This is, most children are taught, how the dinosaurs died 65 million years ago.

    Scientists aren’t all satisfied by that explanation. Since asteroids tend to hit the planet in strange 35 million year cycles, a more massive object must be causing some sort of clockwork effect. Maybe it’s the mysterious elusive Planet X?

    Planet nine orbit image Credit Caltech R. Hurt (IPAC)
    Planet nine orbit image Credit Caltech R. Hurt (IPAC)

    Maybe a set of other strange-acting comets in unstable orbits? Or maybe it’s dark matter. Last year, astrophysicists Lisa Randall and Matthew Reece at Harvard University started pushing a credible if not popular theory that a dense cloud of dark matter sitting along the central plane of the Milky Way could be causing comets, asteroids, and other space objects to head our way on the regular.

    Dark matter cosmic web and the large-scale structure it forms The Millenium Simulation, V. Springel et al
    Dark matter cosmic web and the large-scale structure it forms The Millenium Simulation, V. Springel et al.

    Scientists think about 85 percent of the total matter in the universe is dark, which is pretty mind-boggling consider weve never detected the stuff. Still, there is reason to conclude that it exists because something has to account for the strange gravitational effects we witness in the movements and speeds of the Milky Way and other galaxies. Specifically, Randall and Reece believe a disk of dark matter stretching out a staggering 35 light-years thick is disturbing the trajectory of large asteroids and other objects and flinging them to the Earth. Their analysis of large impact craters on the surface of the planet — more than 12 miles wide, created in past 250 million years — indicates the likelihood these crashes were in some way influenced by the dark matter cycle is three times greater than the odds they are just random events.

    By itself, three-to-one odds aren’t statistically impressive. And, of course, while we kind of know dark matter is a thing, we don’t really know anything about dark matter. But the research itself is a sign that we are beginning to integrate more of what we know about astrophysical phenomena into the deep-time history of life (and death) on Earth. This is maybe the first time someone has linked the mystery of the dinosaurs extinction to the mystery of dark matter.

    One scientist, New York University geologist Michael R. Rampino, take this one step further and suggests that our own solar system actually moves through this cloud of dark matter periodically. Perhaps this movement doesn’t just knock asteroids into us, but it may heat up the planet and cause violent volcanic activity. For this to be true, a lot of other things have to happen. Among them, the dark matter disk has to be more dense than the galaxy’s highest concentration of stars. Also, the dark matter particles need to interact with Earth in such a way as to affect thermo-volcanic activity, but not completely melt the Earth’s core. It’s improbable but far from impossible.

    And that’s not even the weirdest theory that combines extinction and dark matter. Dayong Cao is a Beijing-based researcher who leads the Avoid Earth Extinction Association, an organization dedicated to highlighting and studying potential extraterrestrial threats to our planet (i.e. asteroids). He’s written several papers detailing his ideas on dark matter and asteroids.

    In short, Cao thinks asteroids moving through the dark matter clouds in the Milky Way are then infused with dark matter itself. These “dark asteroids or “dark comets” — which we can’t directly observe — slam into Earth, and bring dark matter to the planet itself. It’s only by studying the gravitational effects of these objects that we can predict if and when they will hit us. Caos theory kind of mashes the previously aforementioned ones into one, super-crazy annihilating idea.

    At this point, the only way to prove any of these theories is to find dark matter. There are detectors running all around the world, though the prevailing thought is that we need to prove dark matter indirectly by better studying its gravitational effect on other celestial objects. Whatever the methods, the day we can finally say weve discovered dark matter could be the day we kill two science birds with one dark-matter soaked stone.

    That is, if dark matter doesn’t manage to kill us off first.

    See the full article here .

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  • richardmitnick 1:48 pm on May 2, 2013 Permalink | Reply
    Tags: , Dark Matter, ,   

    From Fermilab: “New dark matter detector begins search for invisible particles” 

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

    May 2, 2013
    Science contacts:
    Hugh Lippincott, Fermilab, 609-558-6313, hugh@fnal.gov .
    Juan Collar, University of Chicago, 773-702-4253, collar@uchicago.edu

    “Scientists this week heard their first pops in an experiment that searches for signs of dark matter in the form of tiny bubbles.

    This is an image of the first particle interactions seen in the COUPP-60 detector, located half a mile underground at SNOLAB in Ontario, Canada. Photo: SNOLAB

    Scientists will need further analysis to discern whether dark matter caused any of the COUPP-60 experiment’s first bubbles.

    ‘Our goal is to make the most sensitive detector to see signals of particles that we don’t understand,’ said Hugh Lippincott, a postdoc with the Department of Energy’s Fermi National Accelerator Laboratory who has spent much of the past several months leading the installation of the one-of-a-kind detector in a laboratory a mile and a half underground.

    COUPP-60 is a dark-matter experiment funded by DOE’s Office of Science. Fermilab managed the assembly and installation of the experiment’s detector.

    The COUPP-60 detector is a jar filled with purified water and CF3I—an ingredient found in fire extinguishers. The liquid in the detector is kept at a temperature and pressure slightly above the boiling point, but it requires an extra bit of energy to actually form a bubble. When a passing particle enters the detector and disturbs an atom in the clear liquid, it provides that energy.

    Dark-matter particles, which scientists think rarely interact with other matter, should form individual bubbles in the COUPP-60 tank.

    ‘The events are so rare, we’re looking for a couple of events per year,’ Lippincott said.”

    See the full article here.

    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.

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  • richardmitnick 8:38 pm on October 27, 2010 Permalink | Reply
    Tags: Dark Matter,   

    CBS Discovers Dark Matter 

    From Interactions.org

    So, do I have to cross CBS off my list of the news organizations blind to scientific research?

    The CBS headline: “Has Dark Matter Finally Been Seen?

    The CBS article:

    “In a new finding that could have game-changing effects if borne out, two astrophysicists think they’ve finally tracked down the elusive signature of dark matter.
    This view of the gamma-ray sky is constructed from one year of Fermi Large Area Telescope (LAT) observations.
    (Credit: NASA/DOE/Fermi LAT Collaboration)

    This invisible substance is thought to make up much of the universe – but scientists have little idea what it is. They can only infer the existence of dark matter by measuring its gravitational tug on the normal matter that they can see.

    Now, after sifting through observations of the center of our Milky Way galaxy, two researchers think they’ve found evidence of the annihilation of dark matter particles in powerful explosions.

    “Nothing we tried besides dark matter came anywhere close to being able to accommodate the features of the observation,” Dan Hooper, of the Fermi National Accelerator Laboratory in Batavia, Ill., and the University of Chicago, told SPACE.com. “It’s always hard to be sure there isn’t something you just haven’t thought of. But I’ve talked to a lot of experts and so far I haven’t heard anything that was a plausible alternative.”

    Hooper conducted the analysis with Lisa Goodenough, a graduate student at New York University.

    Read the rest of the article here

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