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  • richardmitnick 12:53 pm on November 20, 2018 Permalink | Reply
    Tags: “Nuclear astrophysics is about what goes on inside the star not outside of it”, CASPAR experiment, ,   

    From Notre Dame University: “Unearthing the Secrets of a Star” 

    Notre Dame bloc

    From University of Notre Dame

    The Goal

    The scientists are using space in the Sanford Underground Research Facility (SURF) in Lead, South Dakota, to work on a project called the Compact Accelerator System for Performing Astrophysical Research (CASPAR).


    SURF Above Ground

    CASPAR uses a low-energy particle accelerator that will allow researchers to mimic nuclear fusion reactions in stars. If successful, their findings could help complete our picture of how the elements in our universe are built. “Nuclear astrophysics is about what goes on inside the star, not outside of it,” said Dan Robertson, a Notre Dame assistant research professor of astrophysics working on CASPAR. “It is not observational, but experimental. The idea is to reproduce the stellar environment, to reproduce the reactions within a star.”

    ______________________________________
    “The idea is to reproduce the stellar environment, to reproduce the reactions within a star.”
    ______________________________________

    SURF is located in the former Homestake Gold Mine, which operated for more than a century extracting ore from hundreds of miles of tunnels, thousands of feet below the earth’s surface. That depth is key to projects like CASPAR. With a keen sense of the irony at play, Robertson explains that researchers must “reproduce the stellar environment” by getting as far away from that environment as possible to reduce the cosmic radiation that constantly bombards the earth and creates “noise” which interferes with sensitive physics experiments.

    “When we go underground, there’s a lot of rock above us that’s a mild shielding from cosmic rays,” Robertson said. “Once you get underground, cosmic ray background almost completely disappears.”

    It’s a fairly direct rationale for a project that took a winding path to fruition.

    Finding a Site

    Notre Dame’s involvement with SURF has its origins in a facility called the Deep Underground Science and Engineering Laboratory (DUSEL), planned by the National Science Foundation (NSF) as a complex of laboratories for research in multiple fields: biology, chemistry, geology, as well as physics.

    Notre Dame researchers were especially interested in one aspect of the DUSEL concept called DIANA (Dual Ion Accelerators for Nuclear Astrophysics). And with good reason, according to Robert J. Bernhard, the University’s vice president for research. “The nuclear astrophysics community identified DIANA as a priority, and identified Michael Wiescher to lead that facility,” Bernhard said.

    Wiescher, the Freimann Professor of Nuclear Physics at Notre Dame, led the planning for the DIANA portion of the NSF proposal. That is, right up until sequestration of federal spending made funding of the project impossible. The NSF would eventually ask Wiescher and Notre Dame to withdraw the DIANA proposal, with hopes of one day revisiting it.

    “So the question was, do we just drop it, or do we move ahead?” Wiescher recalls. “And we decided to move ahead, with a smaller scale version.”

    Moving ahead with a smaller project allowed the NSF to still be involved, while a coalition of other partners was formed, including the South Dakota School of Mines and Technology, and Colorado School of Mines. The collaborative nature of CASPAR is indicative of a trend in scientific research at large, and especially at Notre Dame, according to Bernhard. For its part, Notre Dame is strategically investing in labs and equipment that serve multiple researchers and collaborative programs.

    ”Instead of buying equipment for individual labs, we’re directing funding in high performance, shared facilities such as the integrated imaging facility, the center for nano research and technology, the genomics and bioinformatics facility, the mass spectrometry and proteomics facility,” Bernhard said.

    That same philosophy is at work at SURF, which, like CASPAR, has its own indirect path to realization. The Homestake Mine was founded after an expedition led by George Armstrong Custer discovered gold in South Dakota’s Black Hills in 1874. Five years later, the Homestake Mining Company began operations, eventually carving out 370 miles of tunnels as deep as 8,000 feet, creating one of the deepest mines in the country. The gold vein was eventually exhausted after producing 1.25 million kilograms of gold in its lifetime (roughly $80 billion at today’s rates), and Homestake shut down in 2001.

    The closing of Homestake resulted in an economic and identity crisis for Lead and the surrounding area. However, in addition to its gold mining past, Homestake had a unique astrophysics connection.

    2
    The Compact Accelerator System is modular, to allow for transport down the mine shaft.

    In 1965, Ray Davis, a nuclear chemist from Brookhaven National Laboratory, began building an experiment deep in the Homestake mine with the goal of counting neutrinos, subatomic particles produced in fusion reactions inside stars. In 2002, Davis was awarded a share of the Nobel Prize for Physics for his neutrino work at Homestake.

    When Homestake announced it would close the mine, physicists, aware of Davis’ neutrino success, proposed converting it into a deep underground laboratory. In 2004, the South Dakota Legislature created the South Dakota Science and Technology Authority (SDSTA) to work with the scientists proposing the lab. In 2006, Homestake Mining Co. donated the underground mine to the SDSTA. Also in 2006, the SDSTA accepted a $70 million gift from South Dakota philanthropist T. Denny Sanford, who stipulated that $20 million of the donation be used for a Sanford Science Education Center.

    Then the real work began, according to Ani Aprahamian, Notre Dame’s Freimann Professor of Experimental Nuclear Physics and a member of SDSTA’s board.

    “When you have a mine, it’s just people going under to dig at the rock. It’s dirty, filthy,” Aprahamian said. “This is a laboratory that requires a high level of cleanliness, underground. It’s a little bit more than just building a scientific lab, like you would above ground. So the transformation was quite astounding.”

    The first step in that transformation was to pump millions of gallons of water out of the tunnels of the old mine. That task took months. Then came the installation of the power and technology infrastructure required in the roughly 4,400 square feet occupied by CASPAR. Meanwhile, the group of Notre Dame astrophysicists had to devise a way to disassemble and move an accelerator that had been on campus for 10 years to its new underground home.

    “We worked in conjunction with the team at SURF so that everything we designed and built at Notre Dame was modular,” said Robertson. “The idea was that we could dismantle every section and bring it down in much smaller pieces and rebuild it from scratch. We packed it all up into two U-Haul vans and dragged it all the way from campus to SURF.”

    When it arrived, the equipment was brought down the mine shaft via infrastructure originally designed to move men and minerals, not highly sensitive scientific equipment. Robertson recalls the series of roughly two-mile trips from the surface to the underground lab taking upwards of 45 minutes because of the pace at which the conveyances had to travel with accelerator parts on board.

    The Unique Journey to a Unique Lab

    It’s just one of the ways the space’s mining past is meeting its scientific present. Indeed, a visit to CASPAR is unlike a visit to any other laboratory environment. It starts with a comprehensive safety briefing and signing of a series of waivers. Before descending into the mine, one dons overalls, steel-tipped boots, safety goggles and a hard hat and attaches a carbon monoxide detector around the waist. Next, you pick up a gold medallion with a number inscribed on it and enter your name and number on a clipboard. If the medallion is missing at the end of the day, it becomes clear that someone is still underground in the mine. While certainly effective, it’s a fascinating juxtaposition in the highly technical work of exploring the origins of the universe.

    The descent into the mine takes place in a cage that, at most, holds 15 people. The approximately mile-long trip takes 10 minutes without lab equipment, which requires a slower pace and more time. Yet even those 10 minutes can seem longer. The only light in the cage is from a headlamp on the cage operator’s hard hat, which briefly illuminates the wood supports and rock pilings framing the shaft.

    After the descent, you arrive at what is familiarly called the 4850 Level of SURF. You exit into a surprisingly well-lit area with tunnels, or “drifts” in mining parlance, running right and left. CASPAR is located through the left, mile-long tunnel. It’s a startling experience to emerge through the dark tunnel and enter the pristine, high-tech environs of CASPAR. There, Notre Dame researchers and doctoral students have nearly completed reassembly of the accelerator that was shipped in parts from Notre Dame, like an incredibly complex jigsaw puzzle. Experiments are expected to begin in the summer of 2016.

    The groundbreaking scientific breakthroughs the CASPAR researchers are seeking cannot be achieved without the invaluable technical expertise of the former Homestake miners, who were brought back to operate and maintain the mine equipment still being used. The miners and astrophysicists have formed a close working relationship, and Wiescher indicates there is a bond between the two groups that extends beyond just the common workspace.

    “Our goal in CASPAR is to measure the evolution of the elements in the stars,” he said. “There are a number of questions that need to be answered, one being the ratio of carbon to oxygen in our universe. That will be determined by one of the reactions we want to measure. But also, we want to understand the buildup of heavy elements. When you look at old stars – those that came to be around the time of the Big Bang – there are very few elements. You can see in younger stars the elements slowly build up, including heavy elements, such as gold.”

    In other words, Notre Dame researchers are using a retired gold mine in a town called Lead, to determine what reactions lead to the formation of gold in stars, among other things.

    CASPAR is on schedule to be the first such project of its kind to yield results. When it does, Wiescher said the knowledge will have implications across multiple fields of study, most obvious astronomy and the material sciences. Robertson adds that sometimes these kinds of experiments yield other technologies that have broad public familiarity. Nuclear physics experiments have been instrumental in developing MRI and PET scans, for example. While those kinds of outcomes are not an intended goal of projects like CASPAR, Bernhard believes in today’s world they’re nonetheless critical.

    CASPAR at SURF

    3
    Studying the stars from underground

    7
    CASPAR accelerator at SURF

    CASPAR experiment target at SURF

    “Nationally, there is an increasing expectation that universities will be a vehicle of discovery that will continue to provide the basic foundation that will drive better understanding of our world and our future economy,” Bernhard said. “The CASPAR project is an excellent example of this type of research.”

    For now, the precious gold researchers seek is a deeper understanding of our universe. It happens that the best way to do so is to build a deeper lab, where the cosmos can be shut out in hopes of revealing its secrets.

    Produced by the Office of Public Affairs and Communications

    Writers
    Andy Fuller and Bill Gilroy
    Designer
    Nevin McElwrath
    Developer
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    Photographer
    Barbara Johnston
    Videographer
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    Justin Zimmerman

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Notre Dame Campus

    The University of Notre Dame du Lac (or simply Notre Dame /ˌnoʊtərˈdeɪm/ NOH-tər-DAYM) is a Catholic research university located near South Bend, Indiana, in the United States. In French, Notre Dame du Lac means “Our Lady of the Lake” and refers to the university’s patron saint, the Virgin Mary.

    The school was founded by Father Edward Sorin, CSC, who was also its first president. Today, many Holy Cross priests continue to work for the university, including as its president. It was established as an all-male institution on November 26, 1842, on land donated by the Bishop of Vincennes. The university first enrolled women undergraduates in 1972. As of 2013 about 48 percent of the student body was female.[6] Notre Dame’s Catholic character is reflected in its explicit commitment to the Catholic faith, numerous ministries funded by the school, and the architecture around campus. The university is consistently ranked one of the top universities in the United States and as a major global university.

    The university today is organized into five colleges and one professional school, and its graduate program has 15 master’s and 26 doctoral degree programs.[7][8] Over 80% of the university’s 8,000 undergraduates live on campus in one of 29 single-sex residence halls, each of which fields teams for more than a dozen intramural sports, and the university counts approximately 120,000 alumni.[9]

    The university is globally recognized for its Notre Dame School of Architecture, a faculty that teaches (pre-modernist) traditional and classical architecture and urban planning (e.g. following the principles of New Urbanism and New Classical Architecture).[10] It also awards the renowned annual Driehaus Architecture Prize.

     
  • richardmitnick 11:20 am on November 20, 2018 Permalink | Reply
    Tags: CASPAR experiment, Nuclides and Isotopes,   

    From Sanford Underground Research Facility: “A ‘game board’ for astrophysicists” 

    SURF logo
    Sanford Underground levels

    From Sanford Underground Research Facility

    November 19, 2018
    Erin Broberg

    A nuclides chart is designed to help researchers study the nucleosynthesis of elements—or how they are created.

    1
    Matthew Kapust

    Just outside a thick lead door leading to the Compact Accelerator System for Performing Astrophysical Research (CASPAR) in the experiment’s control room, hangs a massive chart. Hundreds of small, colorful blocks identify some of the universe’s smallest units in three vibrant bands that streak across the chart. It is as if an artist took a brush and swiped it across the page. But it isn’t a painting; it’s the chart of nuclides.

    “The periodic table is a chart of atoms, but this is a chart of just the nuclei of those atoms—the stable and unstable isotopes of those atoms,” said Mark Hanhardt, support scientist for Sanford Underground Research Facility (Sanford Lab). “Here, we don’t take into account the electrons at all—just the nucleus.” Hanhardt, a Ph.D. candidate in physics at the South Dakota School of Mines and Technology (SD Mines), is focusing on CASPAR.

    While the periodic table allows scientists to understand the chemical properties of elements, this chart is specifically designed to help researchers study the nucleosynthesis of elements—or how they are created.

    What happens to a nucleus if a neutron is added? If a beta decay occurs? Scientists can locate an element’s nuclei on the chart and visualize the changes that occur at a nuclear level. The numerous details contained in this chart are a bit dizzying. To explain just how this powerful tool is used, Hanhardt has developed a simple analogy.

    “If you add a proton, you move one square up. If you add a neutron, you move one over to the right,” said Hanhardt. “Truly, the chart of nuclides is CASPAR’s game board.”

    The CASPAR collaboration will use a low-energy accelerator to study the creation of elements inside the heart of stars; using this “game board” helps them explore and track the evolution of elements over time.

    The Game Board

    This game board has some three very important rules:

    Rule 1: Start at the beginning.

    The Big Bang created two elements—hydrogen and helium.

    “That is where the elements start,” said Frank Strieder, associate professor of physics at SD Mines and principal investigator for CASPAR. “Over time, they build upon each other, moving their way up the board.”

    Rule 2: Level up.

    From hydrogen and helium, there are multiple ways to “level up” to a heavier element.

    The first is through nuclear fusion, which pushes two elements together, creating a heavier element. Other processes include the slow capture of individual neutrons (called the s-Process), the collision of two stars (called the r-Process) or the beta decay of a neutron.

    Rule 3: Follow the Valley of Stability.

    Isotopes with equal numbers of protons and neutrons are usually more stable than those isotopes with very different numbers. Should a nucleus gain too many of any one particle, it becomes unstable. The thick bands streaking across the chart of nuclides represent what Hanhardt has dubbed the “Valley of Stability.”

    “In this band, the isotopes have a relatively equal number of protons and neutrons in each nucleus, so they tend to be more stable,” said Hanhardt. “As isotopes gain too many protons or neutrons, however, they begin to stray from the main path, further from the Valley of Stability, and the more likely it is that a beta decay will occur.”

    Playing with the s-process

    The rules help researchers better understand how elements can evolve over time. The CASPAR collaboration is most interested in what is called the Slow Neutron Capture Process, or the s-Process. The s-process accounts for the creation of half of all elements heavier than iron.

    “Without the s-process, the universe would be very boring, and it probably would not have complex life,” said Strieder.

    Here’s how the s-process works, according to Hanhardt.

    “Say you start with an element like iron-58. If there is a neutron available, just a free neutron floating around, the iron nucleus can capture it, creating iron-59, another isotope of iron. If that isotope would be stable, it would stick around; however, it is unstable and will undergo beta decay. Beta decay means a neutron is changed into a proton. This will move the nucleus up one and over one to the left on the chart, making it a new element.”

    Through this very slow process, you take a jagged path up the chart, building many of the heavier elements. In order for this process to happen, though, there must be a free neutron available. That’s a bit more difficult that it sounds.

    “Free neutrons only exist on their own for 10-15 minutes before they decay,” Strieder said. “So, in order to create these elements, there has to be a place in the universe where you have neutrons being created, nuclei that are ready to capture a neutron and a temperature just perfect for these reactions to take place.”

    Scientists have a pretty good idea where this happens: in multi-layered stars called thermally pulsing asymptotic giant branch stars (TP-AGB). An example of such a star is “Mira” in the constellation Cetus. What they don’t know, however, is the rate and energy at which the neutrons are produced and captured.

    Two upcoming CASPAR experiments aim to discover just how quickly those neutrons are created and how they join other elements over time.

    3
    New ultraviolet images from NASA’s Galaxy Evolution Explorer show a speeding star that is leaving an enormous trail of “seeds” for new solar systems. The star, named Mira (pronounced my-rah) after the latin word for “wonderful,” is shedding material that will be recycled into new stars, planets and possibly even life as it hurls through our galaxy.

    Defining the Rules

    To study these rates, researchers at CASPAR hope to duplicate the reactions they know occur in TP-AGB stars, creating free neutrons. They will be the first people on earth to study these reactions at a low energy—an energy that is the same in the heart of the star.

    “The astrophysicists take these numbers we discover and put it into their model of how a star works,” said Strieder. “With this, we can determine how much of the heavier elements were produced per star. Then we can calculate the number of heavier elements that were produced in the entire universe, and check if that is consistent with the number of elements we measure on earth.”

    These are big questions to ask of such little reactions. However, it is a fundamental piece in the universal puzzle.

    “If we go back to the game board analogy,” said Hanhardt, “we are not so much looking at one specific move on the board, but rather investigating the rules of the game itself. The really fundamental rules—where do these neutrons come from and how fast do they come?”

    Bechtel Chart of the Nuclides

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

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

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

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

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

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

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

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

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

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

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

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

    Fermilab LBNE
    LBNE

    U Washington Majorana Demonstrator Experiment at SURF

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

    LBNL LZ project at SURF, Lead, SD, USA

    CASPAR at SURF


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

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

     
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