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  • richardmitnick 9:07 am on April 2, 2018 Permalink | Reply
    Tags: , , , , , STFC ISIS Pulsed Neutron Source   

    From STFC: “Why would we want test the robustness of space electronics against neutrons?” 


    STFC

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    STFC ISIS Neutron and Muon Source

    In spite of their size high energy neutrons cause severe disruption to the normal operation of integrated circuits, which make up the advanced electronic devices used in space missions. 🚀 These neutrons are generated by the collision of cosmic rays with the atmosphere, spacecraft components and even the surface of planets. With space missions filled with advanced electronic devices it is of great importance to thoroughly assess their robustness before they even leave the ground.

    Researchers from Italy 🇮🇹 and the UK 🇬🇧 have utilised two neutron beamlines at ISIS Neutron and Muon Source, ChipIr and VESUVIO, to test flash memory devices of interest for space applications.

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    STFC ISIS Neutron and Muon Source

    The beamlines generate neutron spectra similar to that we would expect to see in space and planetary environments. Just one hour in the beam mimics the exposure a device would receive over hundreds of thousands of years in the real environment, allowing researchers to rapidly assess the susceptibility of their device to high-energy neutrons.

    See the full article here .

    Please help promote STEM in your local schools.

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    STFC Hartree Centre

    Helping build a globally competitive, knowledge-based UK economy

    We are a world-leading multi-disciplinary science organisation, and our goal is to deliver economic, societal, scientific and international benefits to the UK and its people – and more broadly to the world. Our strength comes from our distinct but interrelated functions:

    Universities: we support university-based research, innovation and skills development in astronomy, particle physics, nuclear physics, and space science
    Scientific Facilities: we provide access to world-leading, large-scale facilities across a range of physical and life sciences, enabling research, innovation and skills training in these areas
    National Campuses: we work with partners to build National Science and Innovation Campuses based around our National Laboratories to promote academic and industrial collaboration and translation of our research to market through direct interaction with industry
    Inspiring and Involving: we help ensure a future pipeline of skilled and enthusiastic young people by using the excitement of our sciences to encourage wider take-up of STEM subjects in school and future life (science, technology, engineering and mathematics)

    We support an academic community of around 1,700 in particle physics, nuclear physics, and astronomy including space science, who work at more than 50 universities and research institutes in the UK, Europe, Japan and the United States, including a rolling cohort of more than 900 PhD students.

    STFC-funded universities produce physics postgraduates with outstanding high-end scientific, analytic and technical skills who on graduation enjoy almost full employment. Roughly half of our PhD students continue in research, sustaining national capability and creating the bedrock of the UK’s scientific excellence. The remainder – much valued for their numerical, problem solving and project management skills – choose equally important industrial, commercial or government careers.

    Our large-scale scientific facilities in the UK and Europe are used by more than 3,500 users each year, carrying out more than 2,000 experiments and generating around 900 publications. The facilities provide a range of research techniques using neutrons, muons, lasers and x-rays, and high performance computing and complex analysis of large data sets.

    They are used by scientists across a huge variety of science disciplines ranging from the physical and heritage sciences to medicine, biosciences, the environment, energy, and more. These facilities provide a massive productivity boost for UK science, as well as unique capabilities for UK industry.

    Our two Campuses are based around our Rutherford Appleton Laboratory at Harwell in Oxfordshire, and our Daresbury Laboratory in Cheshire – each of which offers a different cluster of technological expertise that underpins and ties together diverse research fields.

    The combination of access to world-class research facilities and scientists, office and laboratory space, business support, and an environment which encourages innovation has proven a compelling combination, attracting start-ups, SMEs and large blue chips such as IBM and Unilever.

    We think our science is awesome – and we know students, teachers and parents think so too. That’s why we run an extensive Public Engagement and science communication programme, ranging from loans to schools of Moon Rocks, funding support for academics to inspire more young people, embedding public engagement in our funded grant programme, and running a series of lectures, travelling exhibitions and visits to our sites across the year.

    Ninety per cent of physics undergraduates say that they were attracted to the course by our sciences, and applications for physics courses are up – despite an overall decline in university enrolment.

     
  • richardmitnick 2:45 pm on January 27, 2018 Permalink | Reply
    Tags: , , Breaking bad metals with neutrons, , , , , , STFC ISIS Pulsed Neutron Source   

    From ANL: “Breaking bad metals with neutrons” 

    ANL Lab

    News from Argonne National Laboratory

    January 11, 2018
    Ron Walli

    `
    A comparison of the theoretical calculations (top row) and inelastic neutron scattering data from ARCS at the Spallation Neutron Source (bottom row) shows the excellent agreement between the two. The three figures represent different slices through the four-dimensional scattering volumes produced by the electronic excitations. (Image by Argonne National Laboratory.)

    By exploiting the properties of neutrons to probe electrons in a metal, a team of researchers led by the U.S. Department of Energy’s (DOE) Argonne National Laboratory has gained new insight into the behavior of correlated electron systems, which are materials that have useful properties such as magnetism or superconductivity.

    The research, to be published in Science, shows how well scientists can predict the properties and functionality of materials, allowing us to explore their potential to be used in novel ways.

    “Our mission from the Department of Energy is to discover and then understand novel materials that could form the basis for completely new applications,” said lead author Ray Osborn, a senior scientist in Argonne’s Neutron and X-ray Scattering Group.

    Osborn and his colleagues studied a strongly correlated electron system (CePd3) using neutron scattering to overcome the limitations of other techniques and reveal how the compound’s electrical properties change at high and low temperatures. Osborn expects the results to inspire similar research.

    “Being able to predict with confidence the behavior of electrons as temperatures change should encourage a much more ambitious coupling of experimental results and models than has been previously attempted,” Osborn said.

    “In many metals, we consider the mobile electrons responsible for electrical conduction as moving independently of each other, only weakly affected by electron-electron repulsion,” he said. “However, there is an important class of materials in which electron-electron interactions are so strong they cannot be ignored.”

    Scientists have studied these strongly correlated electron systems for more than five decades, and one of the most important theoretical predictions is that at high temperatures the electron interactions cause random fluctuations that impede their mobility.

    “They become ‘bad’ metals,” Osborn said. However, at low temperatures, the electronic excitations start to resemble those of normal metals, but with much-reduced electron velocities.

    The existence of this crossover from incoherent random fluctuations at high temperature to coherent electronic states at low temperature had been postulated in 1985 by one of the co-authors, Jon Lawrence, a professor at the University of California, Irvine. Although there is some evidence for it in photoemission experiments, Argonne co-author Stephan Rosenkranz noted that it is very difficult to compare these measurements with realistic theoretical calculations because there are too many uncertainties in modeling the experimental intensities.

    The team, based mainly at Argonne and other DOE laboratories, showed that neutrons probe the electrons in a different way that overcomes the limitations of photoemission spectroscopy and other techniques.

    Making this work possible are advances in neutron spectroscopy at DOE’s Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, a DOE Office of Science User Facility, and the United Kingdom’s ISIS Pulsed Neutron Source, which allow comprehensive measurements over a wide range of energies and momentum transfers. Both played critical roles in this study.

    ORNL Spallation Neutron Source


    ORNL Spallation Neutron Source

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    STFC ISIS Pulsed Neutron Source.

    “Neutrons are absolutely essential for this research,” Osborn said. “Neutron scattering is the only technique that is sensitive to the whole spectrum of electronic fluctuations in four dimensions of momentum and energy, and the only technique that can be reliably compared to realistic theoretical calculations on an absolute intensity scale.”

    With this study, these four-dimensional measurements have now been directly compared to calculations using new computational techniques specially developed for strongly correlated electron systems. The technique, known as Dynamical Mean Field Theory, defines a way of calculating electronic properties that include strong electron-electron interactions.

    Osborn acknowledged the contributions of Eugene Goremychkin, a former Argonne scientist who led the data analysis, and Argonne theorist Hyowon Park, who performed the calculations. The agreement between theory and experiments was “truly remarkable,” Osborn said.

    Looking ahead, researchers are optimistic about closing the gap between the results of condensed matter physics experiments and theoretical models.

    “How do you get to a stage where the models are reliable?” Osborn said. “This paper shows that we can now theoretically model even extremely complex systems. These techniques could accelerate our discovery of new materials.”

    Other Argonne authors of the paper, titled Coherent Band Excitations in CePd3: A Comparison of Neutron Scattering and ab initio Theory, are Park and John-Paul Castellan of the Materials Science Division. Also contributing to this work were researchers at the Joint Institute for Nuclear Research in Russia; the University of Illinois at Chicago; Karlsruhe Institute of Technology in Germany; Oak Ridge National Laboratory; Los Alamos National Laboratory and the University of California at Irvine.

    Research at Argonne and Los Alamos was funded by DOE’s Materials Sciences and Engineering Division of the Office of Basic Energy Sciences. Research at Oak Ridge’s SNS was supported by the Scientific User Facilities Division of the Office of Basic Energy Sciences. Neutron experiments were performed at the SNS and the ISIS Pulsed Neutron Source, Rutherford Appleton Laboratory in the UK. Blues, a high-performance computing cluster operated by the Laboratory Computing Resource Center at Argonne, also contributed to this research.

    See the full article here .

    Please help promote STEM in your local schools.
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    Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation’s first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America’s scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science. For more visit http://www.anl.gov.

    The Advanced Photon Source at Argonne National Laboratory is one of five national synchrotron radiation light sources supported by the U.S. Department of Energy’s Office of Science to carry out applied and basic research to understand, predict, and ultimately control matter and energy at the electronic, atomic, and molecular levels, provide the foundations for new energy technologies, and support DOE missions in energy, environment, and national security. To learn more about the Office of Science X-ray user facilities, visit http://science.energy.gov/user-facilities/basic-energy-sciences/.

    Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science

    Argonne Lab Campus

     
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