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  • richardmitnick 10:04 am on March 10, 2017 Permalink | Reply
    Tags: , , BNL, , , , , , , , Xiaofeng Guo   

    From Brookhaven: Women in STEM – “Secrets to Scientific Success: Planning and Coordination” Xiaofeng Guo 

    Brookhaven Lab

    March 8, 2017
    Lida Tunesi

    1
    Xiaofeng Guo

    Very often there are people behind the scenes of scientific advances, quietly organizing the project’s logistics. New facilities and big collaborations require people to create schedules, manage resources, and communicate among teams. The U.S. Department of Energy’s Brookhaven National Laboratory is lucky to have Xiaofeng Guo in its ranks—a skilled project manager who coordinates projects reaching across the U.S. and around the world.

    Guo, who has a Ph.D. in theoretical physics from Iowa State University, is currently deputy manager for the U.S. role in two upgrades to the ATLAS detector, one of two detectors at CERN’s Large Hadron Collider that found the Higgs boson in 2012.


    CERN ATLAS Higgs Event


    CERN/ATLAS detector

    Brookhaven is the host laboratory for both U.S. ATLAS Phase I and High Luminosity LHC (HL-LHC) upgrade projects, which involve hundreds of millions of dollars and 46 institutions across the nation. The upgrades are complex international endeavors that will allow the detector to make use of the LHC’s ramped up particle collision rates. Guo keeps both the capital and the teams on track.

    “I’m in charge of all business processes, project finance, contracts with institutions, baseline plan reports, progress reports—all aspects of business functions in the U.S. project team. It keeps me very busy,” she laughed. “In the beginning I was thinking ‘in my spare time I can still read physics papers, do my own calculations’… And now I have no spare time!”

    Guo’s dual interest in physics and management developed early in her career.

    “When I was an undergraduate there was a period when I actually signed up for a double major, with classes in finance and economics in addition to physics,” Guo recalled. “I’m happy to explore different things!”

    Later, while teaching physics part-time at Iowa State University, Guo desired career flexibility and studied to be a Chartered Financial Analyst. She passed all required exams in just two years but decided to continue her research after receiving a grant from the National Science Foundation.

    Guo joined Brookhaven Lab in 2010 to fill a need for project management in Nuclear and Particle Physics (NPP). The position offered her a way to learn new skills while staying up-to-date on the physics world.

    Early in her time at Brookhaven, Guo participated in the management of the Heavy Flavor Tracker (HFT) upgrade to the STAR particle detector at the Relativistic Heavy Ion Collider (RHIC), a DOE Office of Science User Facility for nuclear physics research. The project was successfully completed $600,000 under budget and a whole year ahead of schedule.


    BNL/RHIC Star Detector

    “This was a very good learning experience for me. I participated in all the manager meeting discussions, updated the review documents, and helped them handle some contracts. Through this process I learned all the DOE project rules,” Guo said.

    While working on the HFT upgrade, Guo also helped develop successful, large group proposals for increased computational resources in high-energy physics and other fields of science. She joined the ATLAS Upgrade projects after receiving her Project Management Certification, and her physics and finance background as well as experience with large collaborations have enabled her to orchestrate complex planning efforts.

    For the two phases of the U.S. ATLAS upgrade, Guo directly coordinates more than 140 scientists, engineers, and finance personnel, and oversees all business processes, including finance, contracts, and reports. And taking her job one step further, she’s developed entirely new management tools and reporting procedures to keep the multi-institutional effort synchronized.

    “Dr. Guo is one of our brightest stars,” said Berndt Mueller, Associate Lab Director of NPP. “We are fortunate to have her to assist us with many challenging aspects of project development and execution in NPP. In the process of guiding the work of scores of scientists and engineers, she has single-handedly created a unique and essential role in the development of complex projects with an international context, demonstrating skills of unusual depth and breadth and the ability to apply them across a wide array of disciplines.”

    Guo’s management of Phase I won great respect for the project from the high-energy physics community and the Office of Project Assessment (OPA) at the DOE’s Office of Science. The OPA invited her to participate in a panel discussion to share her expertise and help develop project management guidelines that can be used in other Office of Science projects. Guo also worked with BNL’s Project Management Center to help the lab update its own project management system description to meet DOE standards and lay down valuable groundwork for future large projects.

    As the ATLAS Phase I upgrade proceeds through the final construction stage, Guo is simultaneously managing the planning stages of HL-LHC.

    “We haven’t completely defined the project timeline yet, but it’s projected to go all the way to the end of 2025,” Guo said.

    Like Phase I, HL-LHC will ensure ATLAS can perform well while the LHC operates at much higher collision rates so that physicists can further explore the Higgs as well as search for signs of dark matter and extra dimensions.

    Although she admits to missing doing research herself, Guo is not disheartened.

    “I’m still in the physics world; I’m still working with physicists,” she said. “I enjoy working and interacting with people. So I’m happy.”

    Brookhaven’s work on RHIC and ATLAS is funded by the DOE Office of Science.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition
    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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  • richardmitnick 4:07 pm on January 27, 2017 Permalink | Reply
    Tags: BNL, Regeneron Science Talent Search (STS) Competition, Science & Technology, Siemens Competition in Math, What is wrong with this picture?   

    From BNL: “Six Brookhaven Lab-Mentored Students Garner Awards at Regeneron and Siemens Science Competitions” 

    Brookhaven Lab

    January 27, 2017
    Jane Koropsak
    jane@bnl.gov

    [I WOULD LIKE TO KNOW IF ANYONE SEES SOMETHING WRONG WITH THIS PICTURE.]

    Awardees include Regeneron finalist Emily Peterson, Smithtown High School East, who completed her work at Brookhaven.

    Since 1942, students have competed in one of the nation’s most prestigious pre-college science competitions, first in partnership with Westinghouse, then with Intel from 1998 to 2016, and now with Regeneron.

    Regeneron has named the top 300 scholars for its 2017 Science Talent Search (STS) Competition, and three of the selected scholars conducted their research at Brookhaven Lab. One of them—Emily Peterson from Smithtown High School East—has been named a finalist and will be invited to Washington, D.C. in March to participate in final judging and compete for the top award of $250,000. Students compete for more than $3 million in awards, with each scholar receiving a $2,000 award from Regeneron with an additional $2,000 going to his or her school.

    In addition to the Regeneron STS scholars, four Brookhaven students were also named as semifinalists in the annual Siemens competition. The Siemens Foundation established the Siemens Competition in Math, Science & Technology in 1999 to promote excellence by encouraging high school students to undertake individual or team research projects. It fosters intensive research that improves students’ understanding of the value of scientific study and their consideration of future careers in these disciplines.

    “These six students reflect the extraordinary scientific talent being developed on Long Island,” said Kenneth White, manager of the Lab’s Office of Educational Programs. “We have been privileged to host them and many other highly capable students here at the Lab, introducing them to U.S. Department of Energy research. Our congratulations to the six awardees, and many thanks to our Lab mentors.”

    Meet the Regeneron Scholars:

    1
    Finalist Emily Peterson – Woman in STEM

    Finalist Emily Peterson: Smithtown High School East
    Mentor: David Biersach, Information Technology Division
    Title of Project: “Lecithin-Retinol Acyltransferase in Squamous Cell Carcinoma: The Relationship Between Oncology and Wound Repair”

    Emily Peterson met mentor David Biersach at a scientific computing seminar he was giving at her high school, where he learned of her research on skin cancer. Emily’s initial research focused on the possibility that a gene expression problem might inhibit the production of an enzyme responsible for strengthening cell walls. As cancer is invasive, skin cells with weak walls are more susceptible to becoming tumorous. Dave showed Emily how a classic computer algorithm that looks for repeated substrings can be used in a novel way to determine if DNA sequences are likely to have important biological functions. This is accomplished by searching the human genome for other occurrences of these repeated sequences. They discovered that this enzyme’s sequence also occurs in an enzyme involved in blood clotting. When blood clots form to heal a wound, the human body knows to leave the clot alone until the wound is fully repaired. After healing, a chemical signal triggers the body to break down the clot. The similarity in gene sequences that Peterson discovered suggests that cancer cells potentially use the same “don’t bother me” signaling mechanism as blood clots, thus allowing the tumor to continue to grow in stealth mode. This collaboration is an excellent example of how students can apply skills in scientific computing directly to their research projects. Peterson hopes to continue her research by studying the enzyme’s 3D atomic structure.

    2
    Semifinalist Vishrath Kumar

    Semifinalist Vishrath Kumar: Smithtown High School East
    Mentor: Haixin Huang, Collider-Accelerator Department
    Title: “Tune Jump Quadrapole Strength Optimization for AGS Polarization Preservation”

    The spin physics program at Brookhaven Lab’s Relativistic Heavy Ion Collider (RHIC) requires high-energy protons spinning in the same direction. By controlling the direction of the protons’ spins and keeping them aligned, or “polarized,” physicists can tease apart how the protons’ inner building blocks, quarks and gluons, contribute to its spin. A pair of specialized magnets at the Alternating Gradient Synchrotron, the accelerator that injects proton beams into RHIC, helps to mitigate polarization loss. Vishrath’s work is focused on using computer simulations to determine the optimal strength of this pair of magnets and should lead to more precise results.

    Kumar is a participant in the High School Research Program administered by the Lab’s Office of Educational Programs.

    3
    Semifinalist Rushabh Mehta

    Semifinalist Rushabh Mehta: Syosset High School
    Mentor: William Morse, Physics Department
    Title: “Exact Radial Muon Orbit Distortion with E821 BETA-function”

    Rushabh Mehta was named both a Siemens and Regeneron semifinalist for his work with Brookhaven physicist Bill Morse to develop a mathematical formula for calculating how best to control a beam of particles called muons for an upcoming experiment at the U. S. Department of Energy’s Fermilab—one that builds upon Brookhaven Lab’s historic g-2 experiment, which concluded in 2001. Mehta’s research will help in achieving an expected 400-percent improvement in beam quality with 20 times more muons. Using the same ring from the earlier g-2 experiment at Brookhaven, and with far greater precision, scientists from Brookhaven, Fermilab, and other institutions around the world will test a discrepancy between the muon g-2 particle’s theorized “magnetic moment” and the magnetic moment actually measured in the original experiment.

    Mehta is a participant in the High School Research Program administered by the Lab’s Office of Educational Programs.

    Meet the Siemens Semifinalists:

    4
    Semifinalist Daniel Lee
    5
    Semifinalist Brandon Feng

    Mentor: Shinjae Yoo, Computational Science Initiative
    Title of Project: Sensor Network Based Wind Field Detection

    Under the mentorship of Shinjae Yoo, Brandon Feng and Daniel Lee conducted research on sensor network analysis on the Long Island Solar Farm located at Brookhaven Lab. As part of their project, they built a realistic solar irradiance sensor simulator to detect multi-layered wind fields. Feng and Lee also developed robust wind field detection algorithms to determine various properties of data, such as time lag and the correct way to determine the wind field. These meaningful results can be integrated with the sensor network based solar irradiance forecasting framework and possibly applied to real-world data. Under the direction of Yoo, the students will contribute a paper on their findings.

    Feng and Lee are participants in the High School Research Program administered by the Lab’s Office of Educational Programs.

    6
    Semifinalist Bart Voto

    Bart Voto: Manhasset High School
    Mentor: Laura Fierce, Environmental and Climate Sciences Department
    Title of Project: Validating a Parameterization for Absorption by Black Carbon Through Comparisons with Observations

    Black carbon strongly absorbs solar radiation, causing a warming effect on the climate, but absorption per black carbon mass remains uncertain. To evaluate this uncertainty, Voto was tasked with validating a parameterization for light absorption by black carbon against observations. To do this, he used Python (a high-level programming language) to code a parameterization for black carbon’s absorption coefficient (developed previously by Fierce). He then used his code to evaluate the sensitivity of absorption by black carbon to different input parameters and compared the output from the parameterization with the corresponding values from field observations.

    For more information on the Regeneron STS Competition:

    https://www.regeneron.com/science-talent-search

    For more information on the Siemens Competition: https://siemenscompetition.discoveryeducation.com/

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition
    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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  • richardmitnick 3:26 pm on January 20, 2017 Permalink | Reply
    Tags: BNL, Center for Data-Driven Discovery (C3D), Line Pouchard,   

    From BNL: Women in STEM – “Turning Research Data into Scientific Discoveries” Line Pouchard 

    Brookhaven Lab

    January 17, 2017
    Ariana Tantillo

    Line Pouchard, an information specialist in computational science, brings her expertise in big data management and curation to Brookhaven Lab’s Center for Data-Driven Discovery.

    1
    Line Pouchard is a senior researcher at the Center for Data-Driven Discovery, part of Brookhaven Lab’s Computational Science Initiative. No image credit.

    This week, the Center for Data-Driven Discovery (C3D) at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory welcomed its newest member: Line Pouchard, a computational science information specialist. Pouchard joins C3D as a senior researcher.

    Since 2014, Pouchard had been an assistant professor at Purdue University, where she led the investigation of the “scientific big data landscape”—referring to the large number of unique datasets that researchers are generating at unprecedented rates. Her research at Purdue focused on aspects of data management and curation for the storing, sharing, and re-using of research data. Pouchard, who spent 10 years at the beginning of her career as a research scientist at DOE’s Oak Ridge National Laboratory, returns to the DOE complex ready to accelerate data-driven discovery in high-energy physics, nanoscience, biology, and other fields.

    “As an information scientist with a passion for making connections between people and data to discover new knowledge for evidence-based decision-making, I am excited by the opportunity to take on the complex data curation challenges produced by experiments at Brookhaven Lab,” said Pouchard. “I look forward to helping scientists with the discovery, integration, and re-use of data and to providing efficient and effective data delivery systems that advance the state of the art in data curation at DOE and beyond.”

    Part of Brookhaven’s Computational Science Initiative (CSI), C3D is a multidisciplinary center for the development of tools and services—in areas such as machine-learning algorithms, visual analytics approaches, and easily reusable knowledge repositories—to improve the scientific discovery process. C3D’s staff of computational scientists, applied mathematicians, and computer scientists work closely with physicists, biologists, and other scientists to identify and address the challenges of scientific data management and analysis.

    Over her career, Pouchard has designed, developed, and deployed many systems to help scientists discover and integrate the vast wealth of scientific data. Her expertise is in the areas of metadata, semantics, ontologies, and provenance—all ways of “tagging” the data with information about their origins, such as when and how the data were generated, and encoding meaning into the data to facilitate their interrelation and integration. With an MS in information science from the University of Tennessee and a PhD in comparative literature from the City University of New York, Pouchard has a background and skillset that has enabled her to determine and serve the needs of users in a wide variety of domains, including environmental science, high-performance computing, and medicine.

    One of the systems she developed is an online repository of ontology entities for describing satellite and remote-sensing observations, climate simulations, and other earth science datasets. This ontology repository provides detailed descriptions and annotations that help scientists search for and share data, building upon each other’s work. Pouchard also developed a system that collects data on the “health” of a high-performance computing cluster—its temperature, voltage, and power. Collecting machine health data is important in monitoring power consumption, improving resource management, and detecting malware.

    “An experienced scholar in metadata, ontologies, and data provenance, Line will help lead C3D’s efforts to research and create new approaches for gaining, managing, and sharing insights from extreme-scale data collections,” said CSI Director Kerstin Kleese van Dam. “DOE’s large-scale experimental facilities and computing resources are creating unprecedented volumes of data, and Line will play a key role in turning these data into scientific discoveries at Brookhaven.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition
    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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  • richardmitnick 3:08 pm on January 3, 2017 Permalink | Reply
    Tags: , BNL, Center for Functional Nanomaterials (CFN), Nanoscale 'Conversations' Create Complex and Multi-Layered Structures,   

    From BNL: “Nanoscale ‘Conversations’ Create Complex, Multi-Layered Structures” 

    Brookhaven Lab

    December 22, 2016
    Justin Eure

    1
    Study co-authors Pawel Majewski and Kevin Yager preparing nanoscale films of self-assembling materials.

    Building nanomaterials with features spanning just billionths of a meter requires extraordinary precision. Scaling up that construction while increasing complexity presents a significant hurdle to the widespread use of such nano-engineered materials.

    Now, scientists at the U.S. Department of Energy’s Brookhaven National Laboratory have developed a way to efficiently create scalable, multilayer, multi-patterned nanoscale structures with unprecedented complexity.

    The Brookhaven team exploited self-assembly, where materials spontaneous snap together to form the desired structure. But they introduced a significant leap in material intelligence, because each self-assembled layer now guides the configuration of additional layers.

    The results, published in the journal Nature Communications, offer a new paradigm for nanoscale self-assembly, potentially advancing nanotechnology used for medicine, energy generation, and other applications.

    “There’s something amazing and rewarding about creating structures no one has ever seen before,” said study coauthor Kevin Yager, a scientist at Brookhaven Lab’s Center for Functional Nanomaterials (CFN). “We’re calling this responsive layering—like building a tower, but where each brick is intelligent and contains instructions for subsequent bricks.”

    The technique was pioneered entirely at the CFN, a DOE Office of Science User Facility.

    “The trick was chemically ‘sealing’ each layer to make it robust enough that the additional layers don’t disrupt it,” said lead author Atikur Rahman, a Brookhaven Lab postdoc during the study and now an assistant professor at the Indian Institute of Science Education and Research, Pune. “This granted us unprecedented control. We can now stack any sequence of self-organized layers to create increasingly intricate 3D structures.”

    Guiding nanoscale conversations

    2
    The added color in this scanning electron microscope (SEM) image showcases the discrete, self-assembled layers within these novel nanostructures. The pale blue bars are each roughly 4,000 times thinner than a single human hair. No image credit.

    Other nano-fabrication methods—such as lithography—can create precise nano-structures, but the spontaneous ordering of self-assembly makes it faster and easier. Further, responsive layering pushes that efficiency in new directions, enabling, for example, structures with internal channels or pockets that would be exceedingly difficult to make by any other means.

    “Self-assembly is inexpensive and scalable because it’s driven by intrinsic interactions,” said study coauthor and CFN scientist Gregory Doerk. “We avoid the complex tools that are traditionally used to carve precise nano-structures.”

    The CFN collaboration used thin films of block copolymers (BCP)—chains of two distinct molecules linked together. Through well-established techniques, the scientists spread BCP films across a substrate, applied heat, and watched the material self-assemble into a prescribed configuration. Imagine spreading LEGOs over a baking sheet, sticking it in the oven, and then seeing it emerge with each piece elegantly snapped together in perfect order.

    However, these materials are conventionally two-dimensional, and simply stacking them would yield a disordered mess. So the Brookhaven Lab scientists developed a way to have self-assembled layers discretely “talk” to one another.

    The team infused each layer with a vapor of inorganic molecules to seal the structure—a bit like applying nanoscale shellac to preserve a just-assembled puzzle.

    “We tuned the vapor infiltration step so that each layer’s structure exhibits controlled surface contours,” Rahman said. “Subsequent layers then feel and respond to this subtle topography.”

    Coauthor Pawel Majewski added, “Essentially, we open up a ‘conversation’ between layers. The surface patterns drive a kind of topographic crosstalk, and each layer acts as a template for the next one.”

    Exotic configurations

    4
    An aerial view of a complete, self-assembled, multilayer nanostructure. In this instance, parallel bars of block copolymers with varying thickness were criss-crossed. No image credit.

    As often occurs in fundamental research, this crosstalk was an unexpected phenomenon.

    “We were amazed when we first saw templated ordering from one layer to the next, Rahman said. “We knew immediately that we had to exhaustively test all the possible combinations of film layers and explore the technique’s potential.”

    The collaboration demonstrated the formation of a broad range of nano-structures—including many configurations never before observed. Some contained hollow chambers, round pegs, rods, and winding shapes.

    “This was really a Herculean effort on the part of Atikur,” Yager said. “The multi-layer samples covered a staggering range of combinations.”

    Mapping never-before-seen structures

    5
    This image shows the range of multilayer morphologies achieved through this new technique. The first column shows a cross section of the novel 3D nanostructures as captured by scanning electron microscopy (SEM). The computer renderings in the second column highlight the integrity and diversity of each distinct layer, while the overhead SEM view of the third column reveals the complex patterns achieved through the “intelligent” layering. No image credit.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition
    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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  • richardmitnick 3:28 pm on December 23, 2016 Permalink | Reply
    Tags: , BNL, Laser Pulses Help Scientists Tease Apart Complex Electron Interactions,   

    From BNL: “Laser Pulses Help Scientists Tease Apart Complex Electron Interactions” 

    Brookhaven Lab

    December 20, 2016
    Karen McNulty Walsh
    kmcnulty@bnl.gov
    (631) 344-8350

    Peter Genzer
    genzer@bnl.gov
    (631) 344-3174

    1
    A microscopic image of one of the bismuth strontium calcium copper oxide samples the scientists studied using a new high-speed imaging technique. Color changes show changes in sample height and curvature to dramatically reveal the layered structure and flatness of the material. No image credit.

    Scientists studying high temperature superconductors—materials that carry electric current with no energy loss when cooled below a certain temperature—have been searching for ways to study in detail the electron interactions thought to drive this promising property. One big challenge is disentangling the many different types of interactions—for example, separating the effects of electrons interacting with one another from those caused by their interactions with the atoms of the material.

    Now a group of scientists including physicists at the U.S. Department of Energy’s Brookhaven National Laboratory has demonstrated a new laser-driven “stop-action” technique for studying complex electron interactions under dynamic conditions. As described in a paper just published in Nature Communications, they use one very fast, intense “pump” laser to give electrons a blast of energy, and a second “probe” laser to measure the electrons’ energy level and direction of movement as they relax back to their normal state.

    “By varying the time between the ‘pump’ and ‘probe’ laser pulses we can build up a stroboscopic record of what happens—a movie of what this material looks like from rest through the violent interaction to how it settles back down,” said Brookhaven physicist Jonathan Rameau, one of the lead authors on the paper. “It’s like dropping a bowling ball in a bucket of water to cause a big disruption, and then taking pictures at various times afterward,” he explained.

    2
    Brookhaven Lab physicists Peter Johnson (rear) and Jonathan Rameau. No image credit.

    The technique, known as time-resolved, angle-resolved photoelectron spectroscopy (tr-ARPES), combined with complex theoretical simulations and analysis, allowed the team to tease out the sequence and energy “signatures” of different types of electron interactions. They were able to pick out distinct signals of interactions among excited electrons (which happen quickly but don’t dissipate much energy), as well as later-stage random interactions between electrons and the atoms that make up the crystal lattice (which generate friction and lead to gradual energy loss in the form of heat).

    But they also discovered another, unexpected signal—which they say represents a distinct form of extremely efficient energy loss at a particular energy level and timescale between the other two.

    “We see a very strong and peculiar interaction between the excited electrons and the lattice where the electrons are losing most of their energy very rapidly in a coherent, non-random way,” Rameau said. At this special energy level, he explained, the electrons appear to be interacting with lattice atoms all vibrating at a particular frequency—like a tuning fork emitting a single note. When all of the electrons that have the energy required for this unique interaction have given up most of their energy, they start to cool down more slowly by hitting atoms more randomly without striking the “resonant” frequency, he said.

    The frequency of the special lattice interaction “note” is particularly noteworthy, the scientists say, because its energy level corresponds with a “kink” in the energy signature of the same material in its superconducting state, which was first identified by Brookhaven scientists using a static form of ARPES. Following that discovery, many scientists suggested that the kink might have something to do with the material’s ability to become a superconductor, because it is not readily observed above the superconducting temperature.

    But the new time-resolved experiments, which were done on the material well above its superconducting temperature, were able to tease out the subtle signal. These new findings indicate that this special condition exists even when the material is not a superconductor.

    “We know now that this interaction doesn’t just switch on when the material becomes a superconductor; it’s actually always there,” Rameau said.

    The scientists still believe there is something special about the energy level of the unique tuning-fork-like interaction. Other intriguing phenomena have been observed at this same energy level, which Rameau says has been studied in excruciating detail.

    It’s possible, he says, that the one-note lattice interaction plays a role in superconductivity, but requires some still-to-be-determined additional factor to turn the superconductivity on.

    “There is clearly something special about this one note,” Rameau said.

    3
    Members of the research team: Peter Johnson and Jonathan Rameau of Brookhaven Lab with Laurenz Rettig, Manuel Ligges, and Isabella Avigo and their time-resolved ARPES experimental setup at the University Duisburg-Essen, Germany.

    Work at Brookhaven National Laboratory was supported by the Center for Emergent Superconductivity, an Energy Frontier Research Center headquartered at Brookhaven National Laboratory and funded by the DOE Office of Science. Additional funding was provided by the National Science Foundation, the Aspen Center for Physics, the Laboratory Directed Research and Development Program of Lawrence Berkeley National Laboratory, and by the McDevitt bequest at

    Georgetown University. Computational resources were provided by the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility headquartered at Lawrence Berkeley National Laboratory. Additional support came from Deutsche Forschungsgemeinschaft, the Mercator Research Center Ruhr, and from the European Union within the seventh Framework Program.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition
    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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  • richardmitnick 1:35 pm on December 2, 2016 Permalink | Reply
    Tags: , BNL, , Dark Interactions Workshop,   

    From BNL: “Dark Interactions Workshop Hosts Physicists from Around the World” 

    Brookhaven Lab

    November 23, 2016
    Chelsea Whyte

    Dozens of experimental and theoretical physicists convened at the U.S. Department of Energy’s Brookhaven National Laboratory in October for the second biennial Dark Interactions Workshop. Attendees came from universities and laboratories worldwide to discuss current research and possible future searches for dark sector states such as dark matter.

    1

    Two great cosmic mysteries – dark energy and dark matter — make up nearly 95% of the universe’s energy budget. Dark energy is the proposed agent behind the ever-increasing expansion of the universe. Some force must propel the accelerating rate at which the fabric of space is stretching, but its origin and makeup are still unknown. Dark matter, first proposed over 80 years ago, is theorized to be the mass responsible for most of the immense gravitational pull that galaxy clusters exert. Without its presence, galaxies and galaxy clusters shouldn’t hang together as they do, according to the laws of gravity that permeate our cosmos.

    Universe map Sloan Digital Sky Survey (SDSS) 2dF Galaxy Redshift Survey
    Universe map Sloan Digital Sky Survey (SDSS) 2dF Galaxy Redshift Survey

    Scientists know this much. It’s a bit like a map of a continent with the outlines drawn, but large holes that need a lot of filling in. “There are a lot of things we know that we don’t know,” said Brookhaven physicist Ketevi Assamagan, who organized the workshop along with Brookhaven physicists Hooman Davoudiasl and Mary Bishai, and Stony Brook University physicist Rouven Essig.

    The Dark Interactions Workshop was created to gather great minds in search of answers to these cosmic questions, and to share knowledge across the many different types of experiments searching for dark-sector particles. “The goals are to search for several well-motivated dark-sector particles with existing and upcoming experiments, but also to propose new experiments that can lead the search for dark forces in the coming decade. This requires in-depth discussions among theorists and experimentalists,” Essig said.

    The sessions ranged from discussing theories to status updates from dark-particle searches following the first workshop two years ago. Attendees included post-docs as well as tenured scientists, and Assamagan said workshops like this are crucial for allowing a diverse and somewhat disparate group of scientists in a dense field of study to get to know each other’s work and build collaborations.

    “Dark matter is one of the hot topics in particle and astrophysics today. We know that we don’t have the complete story when it comes to our universe. Understanding the nature of dark matter would be a revolution,” Assamagan said.

    While tantalizing theories have directed physicists to build new ways to search for dark sector states, conclusive evidence still eludes scientists. “Since there is currently a vast range of possibilities for what could constitute the dark sector, a variety of innovative approaches for answering this question need to be considered,” Davoudiasl said. “To that end, meetings like this are quite helpful as they facilitate the exchange of new ideas.”

    “There’s still a lot of hope. Meetings like this one show that there are a lot of clever people working in this field and a lot of collaboration between them. Hopefully at our next workshop, we’ll be sharing evidence that we’ve discovered something of the dark sector,” said Assamagan.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition
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    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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  • richardmitnick 7:17 am on November 19, 2016 Permalink | Reply
    Tags: , , BNL, HPE Annie,   

    From BNL: “Brookhaven Lab Advances its Computational Science and Data Analysis Capabilities” 

    Brookhaven Lab

    November 18, 2016
    Ariana Tantillo
    atantillo@bnl.gov

    Using leading-edge computer systems and participating in computing standardization groups, Brookhaven will enhance its ability to support data-driven scientific discoveries

    1
    Members of the commissioning team—(from left to right) Imran Latif, David Free, Mark Lukasczyk, Shigeki Misawa, Tejas Rao, Frank Burstein, and Costin Caramarcu—in front of the newly installed institutional computing cluster at Brookhaven Lab’s Scientific Data and Computing Center.

    At the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory, scientists are producing vast amounts of scientific data. To rapidly process and interpret these data, scientists require advanced computing capabilities—programming tools, numerical models, data-mining algorithms—as well as a state-of-the-art data, computing, and networking infrastructure.

    History of scientific computing at Brookhaven

    Brookhaven Lab has a long-standing history of providing computing resources for large-scale scientific programs. For more than a decade, scientists have been using data analytics capabilities to interpret results from the STAR and PHENIX experiments at the Relativistic Heavy Ion Collider (RHIC), a DOE Office of Science User Facility at Brookhaven, and the ATLAS experiment at the Large Hadron Collider (LHC) in Europe.

    BNL RHIC Campus
    BNL RHIC Campus

    Brookhaven STAR
    Brookhaven STAR

    Brookhaven Phenix
    Brookhaven Phenix

    CERN/ATLAS detector
    CERN/ATLAS detector

    Each second, millions of particle collisions at RHIC and billions at LHC produce hundreds of petabytes of data—one petabyte is equivalent to approximately 13 years of HDTV video, or nearly 60,000 movies—about the collision events and the emergent particles. More than 50,000 computing cores, 250 computer racks, and 85,000 magnetic storage tapes store, process, and distribute these data that help scientists understand the basic forces that shaped the early universe. Brookhaven’s tape archive for storing data files is the largest one in the United States and the fourth largest worldwide. As the U.S. ATLAS Tier 1 computing center—the largest one worldwide—Brookhaven provides about 25 percent of the total computing and storage capacity for LHC’s ATLAS experiment, receiving and delivering approximately two hundred terabytes of data (picture 62 million photos) to more than 100 data centers around the world each day.

    3
    Physicist Srinivasan Rajagopalan with hardware located at Brookhaven Lab that is used to support the ATLAS particle physics experiment at the Large Hadron Collider of CERN, the European Organization for Nuclear Research.

    “This capability to deliver large amounts of computational power makes Brookhaven one of the largest high-throughput computing resources in the country,” said Kerstin Kleese van Dam, director of Brookhaven’s Computational Science Initiative (CSI), which was launched in 2014 to consolidate the lab’s data-centric activities under one umbrella.

    Brookhaven Lab has a more recent history in operating high-performance computing clusters specifically designed for applications involving heavy numerical calculations. In particular, Brookhaven has been home to some of the most powerful supercomputers, including three generations of supercomputers from the New York State–funded IBM Blue Gene series. One generation, New York Blue/L, debuted at number five on the June 2007 top 500 list of the world’s fastest computers. With these high-performance computers, scientists have made calculations critical to research in biology, medicine, materials science, nanoscience, and climate science.

    4
    New York Blue/L is a massively parallel supercomputer that Brookhaven Lab acquired in 2007. At the time, it was the fifth most powerful supercomputer in the world. It was decommissioned in 2014.

    In addition to having supported high-throughput and high-performance computing, Brookhaven has hosted cloud-based computing services for smaller applications, such as analyzing data from cryo-electron microscopy studies of proteins.

    Advanced tools for solving large, complex scientific problems

    Brookhaven is now revitalizing its capabilities for computational science and data analysis so that scientists can more effectively and efficiently solve scientific problems.

    “All of the experiments going on at Brookhaven’s facilities have undergone a technological revolution to some extent,” explained Kleese van Dam. This is especially true with the state-of-the-art National Synchrotron Light Source II (NSLS-II) and the Center for Functional Nanomaterials (CFN)—both DOE Office of Science User Facilities at Brookhaven—each of which continues to attract more users and experiments.

    BNL NSLS-II Interior
    BNL NSLS II
    BNL NSLS II

    BNL Center for Functional Nanomaterials interior
    bnl-cfn-campus
    BNL Center for Functional Nanomaterials

    “The scientists are detecting more things at faster rates and in greater detail. As a result, we have data rates that are so big that no human could possibly make sense of all the generated data—unless they had something like 500 years to do so!” Kleese van Dam continued.

    In addition to analyzing data from experimental user facilities such as NSLS-II, CFN, RHIC, and ATLAS, scientists run numerical models and computer simulations of the behavior of complex systems. For example, they use models based on quantum chromodynamics theory to predict how elementary particles called quarks and gluons interact. They can then compare these predictions with the interactions experimentally studied at RHIC, when the particles are released after ions are smashed together at nearly the speed of light. Other models include those for materials science—to study materials with unique properties such as strong electron interactions that lead to superconductivity, magnetic ordering, and other phenomena—and for chemistry—to calculate the structures and properties of catalysts and other molecules involved in chemical processes.

    To support these computationally intensive tasks, Brookhaven recently installed at its Scientific Data and Computing Center a new institutional computing system from Hewlett Packard Enterprise (HPE). This institutional cluster—a set of computers that work together as a single integrated computing resource—initially consists of more than 100 compute nodes with processing, storage, and networking capabilities.

    4
    BNL Annie HPE supercomputer

    Each node includes both central processing units (CPUs)—the general-purpose processors commonly referred to as the “brains” of the computer—and graphics processing units (GPUs)—processors that are optimized to perform specific calculations. The nodes have error-correcting code memory, a type of data storage that detects and corrects memory corruption caused, for example, by voltage fluctuations on the computer’s motherboard. This error-correcting capability is critical to ensuring the reliability of Brookhaven’s scientific data, which are stored in different places on multiple hard disks so that reading and writing of the data can be done more efficiently and securely. A “file system” software separates the data into groups called “files” that are named so they can be easily found, similar to how paper documents are sorted and put into labeled file folders. Communication between nodes is enabled by a network that can send and receive data at 100 gigabytes per second—a data rate fast enough to copy a Blu-ray disc in mere seconds—with less than microseconds between each unit of data transferred.

    The institutional computing cluster will support a range of high-profile projects, including near-real-time data analysis at the CFN and NSLS-II. This analysis will help scientists understand the structures of biological proteins, the real-time operation of batteries, and other complex problems.

    This cluster will also be used for exascale numerical model development efforts, such as for the new Center for Computational Design of Strongly Correlated Materials and Theoretical Spectroscopy. Led by Brookhaven Lab and Rutgers University with partners from the University of Tennessee and DOE’s Ames Laboratory, this center is developing next-generation methods and software to accurately describe electronic correlations in high-temperature superconductors and other complex materials and a companion database to predict targeted properties with energy-related application to thermoelectric materials. Brookhaven scientists collaborating on two exascale computing application projects that were recently awarded full funding by DOE—“NWChemEx: Tackling Chemical, Materials and Biomolecular Challenges in the Exascale Era” and “Exascale Lattice Gauge Theory Opportunities and Requirements for Nuclear and High Energy Physics”—will also access the institutional cluster.

    “As the complexity of a material increases, more computer resources are required to efficiently perform quantum mechanical calculations that help us understand the material’s properties. For example, we may want to sort through all the different ways that lithium ions can enter a battery electrode, determining the capacity of the resulting battery and the voltage it can support,” explained Mark Hybertsen, leader of the CFN’s Theory and Computation Group. “With the computing capacity of the new cluster, we’ll be able to conduct in-depth research using complicated models of structures involving more than 100 atoms to understand how catalyzed reactions and battery electrodes work.”

    5
    This figure shows the computer-assisted catalyst design for the oxygen reduction reaction (ORR), which is one of the key challenges to advancing the application of fuel cells in clean transportation. Theoretical calculations based on nanoparticle models provide a way to not only speed up this reaction on conventional platinum (Pt) catalysts and enhance their durability, but also to lower the cost of fuel cell production by alloying (combining) Pt catalysts with the less expensive elements nickel (Ni) and gold (Au).

    In the coming year, Brookhaven plans to upgrade the institutional cluster to 200 nodes, which will subsequently be expanded to 300 nodes in the long term.

    “With these additional nodes, we’ll be able to serve a wider user community. Users don’t get just a share of the system; they get to use the whole system at a given time so that they can address very large scientific problems,” Kleese van Dam said.

    Data-driven scientific discovery

    Brookhaven is also building a novel computer architecture test bed for the data analytics community. Using this test bed, CSI scientists will explore different hardware and software, determining which are most important to enabling data-driven scientific discovery.

    Scientists are initially exploring a newly installed Koi Computers system that comprises more than 100 Intel parallel processors for high-performance computing. This system makes use of solid-state drives—storage devices that function like a flash drive or memory stick but reside inside the computer. Unlike traditional hard drives, solid-state drives do not consecutively read and write information by moving a tiny magnet with a motor; instead, the data are directly stored on electronic memory chips. As a result, solid-state drives consume far less power and thus would enable Brookhaven scientists to run computations much more efficiently and cost-effectively.

    “We are enthusiastic to operate these ultimate hardware technologies at the SDCC [Scientific Data and Computing Center] for the benefit of Brookhaven research programs,” said SDCC Director Eric Lançon.

    Next, the team plans to explore architectures and accelerators that could be of particular value to data-intensive applications.

    For data-intensive applications, such as analyzing experimental results using machine learning, the system’s memory input/output (I/O) rate and compute power are important. “A lot of systems have very slow I/O rates, so it’s very time consuming to get the data, only a small portion of which can be worked on at a time,” Kleese van Dam explained. “Right now, scientists collect data during their experiment and take the data home on a hard drive to analyze. In the future, we’d like to provide near-real-time data analysis, which would enable the scientists to optimize their experiments as they are doing them.”

    Participation in computing standards groups

    In conjunction to updating Brookhaven’s high-performance computing infrastructure, CSI scientists are becoming more involved in standardization groups for leading parallel programming models.

    “By participating in these groups, we’re making sure the high-performance computing standards are highly supportive of our scientists’ requirements for their experiments,” said Kleese van Dam.

    Currently, CSI scientists are in the process of applying to join the OpenMP (for Multi-Processing) Architecture Review Board. This nonprofit technology consortium manages the OpenMP application programming interface (API) specification for parallel programming on shared-memory systems—those in which individual processes can communicate and share data by using a common memory.

    In June 2016, Brookhaven became a member of the OpenACC (short for Open Accelerators) consortium. As part of this community of more than 20 research institutions, supercomputing centers, and technology developers, Brookhaven will help determine the future direction of the OpenACC programming standard for parallel computing.

    6
    (From left to right) Robert Riccobono, Nicholas D’Imperio, and Rafael Perez with a NVIDIA Tesla graphics processing unit (GPU) and a Hewlett Packard compute node, where the GPU resides. No image credit.

    The OpenACC API simplifies the programming of computer systems that combine traditional core processors with accelerator devices, such as GPUs and co-processors. The standard describes a set of instructions that identify computationally intensive parts of the code in common programming languages to be offloaded from a primary host processor to an accelerator. Distributing the processing load enables more efficient computations—like the many that Brookhaven scientists require to analyze the data they generate at RHIC, NSLS-II, and CFN.

    “From imaging the complex structures of biological proteins at NSLS-II, to capturing the real-time operation of batteries at CFN, to recreating exotic states of matter at RHIC, scientists are rapidly producing very large and varied datasets,” said Kleese van Dam. “The scientists need sufficient computational resources for interpreting these data and extracting key information to make scientific discoveries that could lead to the next pharmaceutical drug, longer-lasting battery, or discovery in physics.”

    As an OpenACC member, Brookhaven Lab will help implement the features of the latest C++ programming language standard into OpenACC software. This effort will directly support the new institutional cluster that Brookhaven purchased from HPE.

    “When programming advanced computer systems such as the institutional cluster, scientific software developers face several challenges, one of which is transferring data resident in main system memory to local memory resident on an accelerator such as a GPU,” said computer scientist Nicholas D’Imperio, chair of Brookhaven’s Computational Science Laboratory for advanced algorithm development and optimization. “By contributing to the capabilities of OpenACC, we hope to reduce the complexity inherent in such challenges and enable programming at a higher level of abstraction.”

    A centralized Computational Science Initiative

    These standards development efforts and technology upgrades come at a time when CSI is bringing all of its computer science and applied mathematics research under one roof. In October 2016, CSI staff moved into a building that will accommodate a rapidly growing team and will include collaborative spaces where Brookhaven Lab scientists and facility users can work with CSI experts. The building comprises approximately 60,000 square feet of open space that Brookhaven Lab, with the support of DOE, will develop into a new data center to house its growing data, computing, and networking infrastructure.

    “We look forward to the data-driven scientific discoveries that will come from these collaborations and the use of the new computing technology,” said Kleese van Dam.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition
    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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  • richardmitnick 10:24 am on October 14, 2016 Permalink | Reply
    Tags: BNL, Highly sensitive X-ray scattering shows why an exotic material is sometimes a metal sometimes an insulator, Paul Scherrer Institute   

    From BNL: “Highly sensitive X-ray scattering shows why an exotic material is sometimes a metal, sometimes an insulator” 

    Brookhaven Lab

    3

    Paul Scherrer Institute

    October 11, 2016

    The following news release was published today by the Paul Scherrer Institute (PSI) and appears here in its original format. Valentina Bisogni, an assistant physicist at Brookhaven National Laboratory’s National Synchrotron Light Source, a U.S. Department of Energy User Facility, performed resonant inelastic x-ray scattering (RIXS) measurements and data analysis for the work below while serving as a post-doc at PSI.

    BNL NSLS-II Building
    BNL NSLS-II Interior
    NSLS II

    In her current position at NSLS-II, she works at the Soft Inelastic X-ray Scattering (SIX) beamline to build a state-of-the-art RIXS spectrometer, designed to achieve 100’000 resolving power. The SIX beamline will be available for visiting scientists next year and will offer an extremely high energy resolution to characterize electronic and magnetic excitations in energy materials.

    For more information about Brookhaven’s role, contact Chelsea Whyte at 631.344.8671, cwhyte@bnl.gov or Peter Genzer at 631.344.3174, genzer@bnl.gov.

    1
    From the left, Sara Catalano (University of Geneva), Thorsten Schmitt (PSI), Marta Gibert (University of Geneva), at the ADRESS beamline of Swiss Light Source in front of SAXES, the 5m-long spectrometer for Resonant Inelastic X-ray Scattering (RIXS) used for the published study.

    Some materials hold surprising – and possibly useful – properties: Neodymium nickel oxide is either a metal or an insulator, depending on its temperature. This characteristic makes the material a potential candidate for transistors in modern electronic devices. To understand how neodymium nickel oxide makes the transition from metal to insulator, researchers at the Paul Scherrer Institute PSI and the University of Geneva have precisely probed the distribution of electrons in the material. By means of a sophisticated development of X-ray scattering, they were able to show that electrons in the vicinity of the material’s oxygen atoms are rearranging. The researchers have now published their study in the journal Nature Communications.

    Computers, smartphones, and all kinds of other electronic devices have tiny transistors as their basic elements. Up to now, these have been realised with so-called semiconductors. It’s possible that semiconductors might one day get competition from a certain class of oxide materials. Some of these materials can be switched between being an insulator and an electrically conductive metal. Thus they could also be used to build transistors.

    To gain a fundamental understanding of the phase transition from metal to insulator in these materials, researchers at the Paul Scherrer Institute PSI and the University of Geneva, together with scientists at the University of British Columbia in Canada, looked at one representative of this class of materials: neodymium nickel oxide (NdNiO3). Above a temperature of around 150 Kelvin (minus 123 degrees Celsius), the material is a metal and thus conducts electric current. Below this temperature, in contrast, it is an insulator and therefore non-conducting.

    The mystery of the phase transition

    Since the arrangement of electrons in the material is responsible for these properties, the researchers wanted first to find out what was going on with this arrangement. Or, to put it in the scientists’ language, which energetic states the electrons in the material take — that is, how the nickel and oxygen orbitals are occupied in this specific case. “For the material as a whole we call this its electronic structure,” says Thorsten Schmitt of the PSI. In particular, the researchers wanted to find out how this electronic structure differs in its two states — metal and insulator.

    Schmitt is leader of the research group Spectroscopy of Novel Materials at PSI. At the Swiss Light Source SLS, he and his team carry out Raman spectroscopy with X-rays. To measure the electronic structure of neodymium nickel oxide, they used the refined method of resonant inelastic X-ray scattering, or RIXS.

    Measurements with highly sensitive resonant X-ray scattering

    With RIXS, electrons in the system are resonantly excited. “That means the energy of the irradiating X-ray light is selected in such a way that it lifts electrons from one particular electron orbital into another,” Schmitt explains. In this case, the researchers chose a specific electron transition in nickel. When, after excitation, the electrons in the system fall back along any number of different paths, they send out light at specific energies that correspond to energy intervals existing in the system. The electronic structure of the material can thus be measured through the recorded spectral lines.

    To determine the irradiation energy for resonant excitation of the nickel transition, the researchers first acquired an absorption spectrum. This showed the resonance energy at around 853 electronvolts.

    The next measurement, then, consisted of recording RIXS spectra for many different irradiation energies. For this the researchers took advantage of the possibility to vary the energy at the ADRESS beamline of the SLS. In this way, they recorded 80 spectra that lay below as well as above the resonance energy. When aligned, these spectra yielded a two-dimensional “carpet”: a graphic that plots the RIXS spectra with reference to the energy of irradiation.

    2
    Thorsten Schmitt (PSI) setting the cooling for the high-resolution CCD detector installed on the SAXES spectrometer.

    “Because we scan the radiated energy around the resonance, we are able to distinguish which component in our RIXS spectra comes from electrons localised around nickel and which comes from the electrons of the oxygen atoms,” explains Valentina Bisogni, first author of the new study. The principle: Electrons associated with nickel respond more strongly at the resonance energy; away from the resonance, in contrast, the share of electrons associated with oxygen can be seen.

    Notably, the researchers conducted this experiment twice — first at 300 Kelvin, far above the transition temperature and thus in the region where neodymium nickel oxide behaves like a metal. They then ran the experiment a second time at a frosty 15 Kelvin, far below the transition temperature and thus in the region where the material is an insulator. Each RIXS “carpet” on its own showed the researchers the electronic structure of the material in that particular state. And the comparison of the two “carpets” revealed which changes in the electronic structure are responsible for the phase transition from metal to insulator.

    Electrons are rearranging in the vicinity of the oxygen atoms

    The result: During the phase transition from metal to insulator, the electronic structure of the nickel atoms remains the same. Each nickel atom, however, is surrounded by six oxygen atoms, and in the metallic state these six atoms altogether are missing two electrons. In the insulating state, on the other hand, the six oxygen atoms alternately have their normal electronic structure or rather are missing twice as many — that is, four — electrons.

    To make a long story short: The change takes place exclusively in the vicinity of the oxygen atoms.

    Theoretical calculations, Schmitt explains, have for several years suggested that the changes might not take place in the region of the nickel atoms but rather in the vicinity of the oxygen atoms. “Now at the SLS,” he says, “we have obtained definitive experimental proof.”

    With their experiment, the researchers have not only ascertained the cause of the metal-insulator transition in neodymium nickel oxide; at the same time, they have demonstrated how the RIXS technique can be used more broadly to understand the complex electronic structures of materials.

    Thin-film fabrication at the University of Geneva

    The sample of neodymium nickel oxide material with which the researchers carried out their measurements at the SLS was fabricated by collaborators at the University of Geneva. For RIXS measurements, it was essential to have the material available in single-crystal form. Up to now, however, this could be realised only as a thin film. The finesse of the Geneva researchers lay in manipulating the properties of the thin film in such a way — using a suitable substrate — that they matched those of a three-dimensional piece of the material.

    Potential applications in electronics

    The material’s phase transition between metal and insulator could be realised not only through temperature, but also through the application of an electrical voltage, Schmitt stresses. This could be exploited if such materials should one day find their way into electronics.

    At present, their research on this particular class of oxides is still considered basic research, says PSI scientist Schmitt. But this step is indispensable: “To be able to do good applied research, we have to do good fundamental research.”

    In brief:

    The material neodymium nickel oxide can be a metal or an insulator, depending on the temperature.

    At around 150 Kelvin (minus 123 degrees Celsius), the state changes: above this temperature it is metallic, below insulating.

    The studies were conducted at 300 Kelvin (27 degrees Celsius, metallic) and 15 Kelvin (minus 258 degrees Celsius, insulating).

    The experimental method is a novel, sophisticated development in the field of resonant inelastic X-ray scattering (RIXS).

    The researchers recorded 80 RIXS spectra in the energy domain of around 853 electronvolts.

    The result of the study: The electronic structure of the material differs in the vicinity of the oxygen atoms, depending on the temperature; this is responsible for the metallic or, respectively, insulating properties.

    Text: Paul Scherrer Institute/Laura Hennemann

    About PSI

    6

    The Paul Scherrer Institute PSI develops, builds and operates large, complex research facilities and makes them available to the national and international research community. The institute’s own key research priorities are in the fields of matter and materials, energy and environment and human health. PSI is committed to the training of future generations. Therefore about one quarter of our staff are post-docs, post-graduates or apprentices. Altogether PSI employs 2000 people, thus being the largest research institute in Switzerland. The annual budget amounts to approximately CHF 370 million. PSI is part of the ETH Domain, with the other members being the two Swiss Federal Institutes of Technology, ETH Zurich and EPFL Lausanne, as well as Eawag (Swiss Federal Institute of Aquatic Science and Technology), Empa (Swiss Federal Laboratories for Materials Science and Technology) and WSL (Swiss Federal Institute for Forest, Snow and Landscape Research).

    Contact

    Thorsten Schmitt, Head of the research group Spectroscopy of Novel Materials, Laboratory for Condensed Matter and Materials Science, Paul Scherrer Institute
    Telephone: +41 56 310 37 62, e-mail: thorsten.schmitt@psi.ch [german, english]

    Original Publication

    Ground state oxygen holes and the metal-insulator transition in the negative charge-transfer rare-earth nickelates
    V. Bisogni, S. Catalano, R. Green, M. Gibert, R. Scherwitzl, Y. Huang, V. Strocov, P. Zubko, S. Balandeh, J.-M. Triscone, G. Sawatzky, T. Schmitt
    Nature Communications

    See the full article here .

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    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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  • richardmitnick 11:12 am on October 7, 2016 Permalink | Reply
    Tags: BNL, Brookhaven Lab to Play Major Role in Two DOE Exascale Computing Application Projects, Computational Science Initiative (CSI), Exascale Lattice Gauge Theory Opportunities and Requirements for Nuclear and High Energy Physics, Materials and Biomolecular Challenges in the Exascale Era, NWChemEx: Tackling Chemical,   

    From BNL: “Brookhaven Lab to Play Major Role in Two DOE Exascale Computing Application Projects” 

    Brookhaven Lab

    October 5, 2016
    Ariana Tantillo
    atantillo@bnl.gov
    (631) 344-2347
    Peter Genzer
    genzer@bnl.gov
    (631) 344-3174

    BNL NSLS-II Building
    BNL NSLS-II Interior
    BNL NSLS-II

    Scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory will play major roles in two of the 15 fully funded application development proposals recently selected by the DOE’s Exascale Computing Project (ECP) in its first-round funding of $39.8 million. Seven other proposals received seed funding.

    The ECP’s mission is to maximize the benefits of high-performance computing for U.S. economic competitiveness, national security, and scientific discovery. Specifically, the development efforts will focus on advanced modeling and simulation applications for next-generation supercomputers to enable advances in climate and environmental science, precision medicine, cosmology, materials science, and other fields. Led by teams from national labs, research organizations, and universities, these efforts will help guide DOE’s development of a U.S. exascale computing ecosystem. Exascale computing refers to systems that can perform at least a billion-billion calculations per second, or a factor of 50 to 100 times faster than the nation’s most powerful supercomputers in use today.

    At Brookhaven Lab, the Computational Science Initiative (CSI) is focused on developing extreme-scale numerical modeling codes that enable new scientific discoveries in collaboration with Brookhaven’s state-of-the-art experimental facilities, including the National Synchrotron Light Source II, the Center for Functional Nanomaterials, and the Relativistic Heavy Ion Collider—all DOE Office of Science User Facilities.

    BNL RHIC Campus
    BNL/RHIC
    BNL/RHIC

    This initiative brings together computer scientists, applied mathematicians, and computational scientists to develop and extend modeling capabilities in areas such as quantum chromodynamics, materials science, chemistry, biology, and climate science.

    “Founded only in December 2015, CSI has for the first time brought together leading experts across the lab to address the challenges of exascale computing. The two successful DOE Exascale Computing Project proposals demonstrate the strength of this interdisciplinary team,” said CSI Director Kerstin Kleese van Dam.

    Computational physics

    One of the two projects Brookhaven Lab will contribute to is called “Exascale Lattice Gauge Theory Opportunities and Requirements for Nuclear and High Energy Physics,” led by Fermi National Accelerator Laboratory. Collaborators on the project are DOE’s Jefferson Lab, Boston University, Columbia University, University of Utah, Indiana University, University of Illinois Urbana-Champaign, Stony Brook University, and College of William & Mary.

    The team at Brookhaven will develop algorithms, language environments, and application codes that will enable scientists to perform lattice quantum chromodynamics (QCD) calculations on next-generation supercomputers. These calculations, along with experimental data produced by particle collisions at Brookhaven’s Relativistic Heavy Ion Collider and other facilities, help physicists understand the fundamental interactions between elementary particles called quarks and gluons that represent 99% of the mass in the visible universe.

    Brookhaven physicist Chulwoo Jung and Brookhaven collaborator Peter Boyle of the University of Edinburgh will apply their expertise in QCD and lead the efforts to design new algorithms and software frameworks that are crucial for the success of lattice QCD on exascale machines. Barbara Chapman, head of Brookhaven’s Computer Science and Mathematics Group and a professor in the Computer Science Department at Stony Brook University, and Brookhaven computational scientist Meifeng Lin will tackle the challenge of developing high-performance programing models that will enable scientists to create software with portable performance across different exascale architectures.

    Computational chemistry

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    Scientists used x-rays at Brookhaven Lab’s National Synchrotron National Light Source to determine the structure of the proton-regulated calcium channel (ribbons) that is shown above embedded in a lipid bilayer (spheres). This system will be the focus of one of the science challenges of the NWChemEx exascale computing project. The members of the project team will use the computational chemistry code they are developing—called NWChemEx—to help them understand what mechanisms underlie proton transfer and how to control calcium leakage for improved stress resistance in plants.

    The other project that Brookhaven will contribute to, “NWChemEx: Tackling Chemical, Materials and Biomolecular Challenges in the Exascale Era,” will improve the scalability, performance, extensibility, and portability of the popular computational chemistry code NWChem to take full advantage of exascale computing technologies. Robert Harrison, chief scientist of CSI and director of Stony Brook University’s Institute for Advanced Computational Science, will serve as chief architect, working with project director Thom Dunning of Pacific Northwest National Laboratory (PNNL) and deputy project director Theresa Windus of Ames National Laboratory to oversee a team of computational chemists, computer scientists, and applied mathematicians. Argonne, Lawrence Berkeley, and Oak Ridge national labs and Virginia Tech are partners on the project.

    The team will work to redesign the architecture of NWChem so that it is compatible with the pre-exascale and exascale computers to be deployed at the DOE’s Leadership Computing Facilities and the National Energy Research Scientific Computing Center. This effort will be guided by the requirements of scientific challenges in two application areas related to biomass-based energy production: developing energy crops that are resilient to adverse environmental conditions such as drought and salinity (led by Brookhaven structural biologist Qun Liu) and designing catalytic processes for sustainable biomass-to-fuel conversion (led by PNNL scientists).

    Hubertus van Dam, a computational chemist at Brookhaven, will lead the testing and assessment efforts, which are designed to ensure that the project outcomes optimize societal impact. To achieve this goal, the team’s science challenge domain experts will identify requirements—for example, the ability to build structural models from hundreds of thousands of atoms—that will be translated into computational problems of increasing complexity. As the team develops NWChemEx, it will assess the code’s ability to solve these problems.

    A complete list of the 22 selected projects can be found in the press release issued by DOE.

    The ECP is a collaborative effort of two DOE organizations—the Office of Science and the National Nuclear Security Administration. As part of President Obama’s National Strategic Computing Initiative, ECP was established to develop a capable exascale ecosystem, encompassing applications, system software, hardware technologies and architectures, and workforce development to meet the scientific and national security mission needs of DOE in the mid-2020s timeframe.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition
    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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  • richardmitnick 9:32 am on September 29, 2016 Permalink | Reply
    Tags: BNL, , Room-Temp Superconductors Could Be Possible   

    From BNL: “Room-Temp Superconductors Could Be Possible” 

    Brookhaven Lab

    September 27, 2016
    Ariana Tantillo

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    This composite image offers a glimpse inside the custom system Brookhaven scientists used to create samples of materials that may pave the way for high-temperature superconductors. | Image courtesy of Brookhaven National Lab.

    SUPERCONDUCTORS ARE THE HOLY GRAIL OF ENERGY EFFICIENCY.

    These mind-boggling materials allow electric current to flow freely without resistance. But that generally only happens at temperatures within a few degrees of absolute zero (minus 459 degrees Fahrenheit), making them difficult to deploy today. However, if we’re able to harness the powers of superconductivity at room temperature, we could transform how energy is produced, stored, distributed and used around the globe.

    In a recent breakthrough, scientists at the Department of Energy’s Brookhaven National Laboratory got one step closer to understanding how to make that possible. The research, led by physicist Ivan Bozovic, involves a class of compounds called cuprates, which contain layers of copper and oxygen atoms.

    Under the right conditions — which, right now, include ultra-chilly temperatures — electrical current flows freely through these cuprate superconductors without encountering any “roadblocks” along the way. That means none of the electrical energy they’re carrying gets converted to heat. If you’ve ever rested your laptop on your lap, you’ve felt the heat lost by a non-superconducting material.

    Creating the right conditions for superconductivity in cuprates also involves adding other chemical elements such as strontium. Somehow, adding those atoms and chilling the material causes electrons — which normally repel one another — to pair up and effortlessly move together through the material. What makes cuprates so special is that they can achieve this “magical” state of matter at temperatures a hundred degrees or more above those required by standard superconductors. That makes them very promising for real-world, energy-saving applications.

    These materials wouldn’t require any cooling, so they’d be relatively easy and inexpensive to incorporate into our everyday lives. Picture power grids that never lose energy, more affordable mag-lev train systems, cheaper medical imaging machines like MRI scanners, and smaller yet powerful supercomputers.

    To figure out the mystery of “high-temperature” superconductivity in the cuprates, scientists need to understand how the electrons in these materials behave. Bozovic’s team has now solved part of the mystery by determining what exactly controls the temperature at which cuprates become superconducting.

    The standard theory of superconductivity says that this temperature is controlled by the strength of the electron-pairing interaction, but Bozovic’s team has discovered otherwise. After 10 years of preparing and analyzing more than 2,000 samples of a cuprate with varying amounts of strontium, they found that the number of electron pairs within a given area (say, per cubic centimeter), or the density of electron pairs, controls the superconducting transition temperature. In other words, it’s not the forces between objects that matter here, but the density of objects–in this case, electron pairs.

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    A bonding structure of copper and oxygen atoms on a plane within a cuprate. No image credit.

    The scientists arrived at this conclusion by measuring how far a magnetic field was able to get through each sample. This distance is directly related to the density of electron pairs, and the distance differs depending on the material’s properties. In superconductors, the magnetic field is mostly expelled; in metals, the magnetic field permeates. With too much strontium, the cuprate becomes more conductive because the number of mobile electrons increases. Yet the scientists found that as they added more strontium, the number of electron pairs decreased until absolutely no electrons paired up at all. At the same time, the superconducting transition temperature dropped toward zero. Bozovic and his team were quite surprised at this discovery that only a fraction of the electrons paired up, even though they all should have.

    Think of it like this: You’re in a dance hall, and at some point, you and the other people — who normally wouldn’t be caught arm-in-arm — begin to pair up and move in unison. Some newcomers arrive, and they too pair up and join the harmonious dance. But then something strange happens. No matter how many more people make their way to the dance floor, only a fraction of them pair, even though they are all free to do so. Eventually, nobody pairs up at all.

    Why do the dancers, or electrons, pair up in the first place? Answering that question is the next step toward unlocking the mechanism of high-temperature superconductivity in the cuprates — a mystery that’s been puzzling physicists for more than 30 years.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition
    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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