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  • richardmitnick 4:16 pm on November 9, 2018 Permalink | Reply
    Tags: , BNL, NSLS-II’s Coherent Soft X-ray scattering (CSX) beamline, The metal-insulator transition in the correlated material magnetite is a two-step process, Unlocking the Secrets of Metal-Insulator Transitions, , XPCS- x-ray photon correlation spectroscopy   

    From Brookhaven National Lab: “Unlocking the Secrets of Metal-Insulator Transitions” 

    From Brookhaven National Lab

    November 8, 2018

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

    Written by Allison Gasparini

    X-ray photon correlation spectroscopy at NSLS-II’s CSX beamline used to understand electrical conductivity transitions in magnetite.

    1
    Professor Roopali Kukreja from the University of California in Davis and the CSX team Wen Hu, Claudio Mazzoli, and Andi Barbour prepare the beamline for the next set of experiments.

    By using an x-ray technique available at the National Synchrotron Light Source II (NSLS-II), scientists found that the metal-insulator transition in the correlated material magnetite is a two-step process. The researchers from the University of California Davis published their paper in the journal Physical Review Letters. NSLS-II, a U.S. Department of Energy (DOE) Office of Science user facility located at Brookhaven National Laboratory, has unique features that allow the technique to be applied with stability and control over long periods of time.

    “Correlated materials have interesting electronic, magnetic, and structural properties, and we try to understand how those properties change when their temperature is changed or under the application of light pulses, or an electric field” said Roopali Kukreja, a UC Davis professor and the lead author of the paper. One such property is electrical conductivity, which determines whether a material is metallic or an insulator.

    If a material is a good conductor of electricity, it is usually metallic, and if it is not, it is then known as an insulator. In the case of magnetite, temperature can change whether the material is a conductor or insulator. For the published study, the researchers’ goal was to see how the magnetite changed from insulator to metallic at the atomic level as it got hotter.

    In any material, there is a specific arrangement of electrons within each of its billions of atoms. This ordering of electrons is important because it dictates a material’s properties, for example its conductivity. To understand the metal-insulator transition of magnetite, the researchers needed a way to watch how the arrangement of the electrons in the material changed with the alteration of temperature.

    “This electronic arrangement is related to why we believe magnetite becomes an insulator,” said Kukreja. However, studying this arrangement and how it changes under different conditions required the scientists to be able to look at the magnetite at a super-tiny scale.

    2
    Roopali Kukreja (L), the lead author of the paper with Andi Barbour (R), CSX beamline scientist, work closely together while setting up the next set of measurements.

    The technique, known as x-ray photon correlation spectroscopy (XPCS), available at NSLS-II’s Coherent Soft X-ray scattering (CSX) beamline, allowed the researchers to look at how the material changed at the nanoscale—on the order of billionths of a meter.

    “CSX is designed for soft x-ray coherent scattering. This means that the beamline exploits our ultrabright, stable and coherent source of x-rays to analyze how the electron’s arrangement changes over time,” explained Andi Barbour, a CSX scientist who is a coauthor on the paper. “The excellent stability allows researchers to investigate tiny variations over hours so that the intrinsic electron behavior in materials can be revealed.”

    However, this is not directly visible so XPCS uses a trick to reveal the information.

    “The XPCS technique is a coherent scattering method capable of probing dynamics in a condensed matter system. A speckle pattern is generated when a coherent x-ray beam is scattered from a sample, as a fingerprint of its inhomogeneity in real space,” said Wen Hu, a scientist at CSX and co-author of the paper.

    Scientists can then apply different conditions to their material and if the speckle pattern changes, it means the electron ordering in the sample is changing. “Essentially, XPCS measures how much time it takes for a speckle’s intensity to become very different from the average intensity, which is known as decorrelation,” said Claudio Mazzoli, the lead beamline scientist at the CSX beamline. “Considering many speckles at once, the ensemble decorrelation time is the signature of the dynamic timescale for a given sample condition.”

    The technique revealed that the metal-insulator transition is not a one step process, as was previously thought, but actually happens in two steps.

    “What we expected was that things would go faster and faster while warming up. What we saw was that things get faster and faster and then they slow down. So the fast phase is one step and the second step is the slowing down, and that needs to happen before the material becomes metallic,” said Kukreja. The scientists suspect that the slowing down occurs because, during the phase change, the metallic and insulating properties actually exist at the same time in the material.

    “This study shows that these nanometer length scales are really important for these materials,” said Kukreja. “We can’t access this information and these experimental parameters anywhere else than at the CSX beamline of NSLS-II.”

    This research was funded by the National Science Foundation, the Air Force Office of Scientific Research, and the University of California’s Multicampus Research Programs and Initiatives.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    BNL Campus

    BNL NSLS-II


    BNL NSLS II

    BNL RHIC Campus

    BNL/RHIC Star Detector

    BNL RHIC PHENIX

    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 3:55 pm on November 9, 2018 Permalink | Reply
    Tags: BNL, Minerva NVIDIA's latest deep learning high-performance computing system, the DGX-2   

    From Brookhaven National Lab: “Leading-edge AI Computing System now at Home with Brookhaven Lab’s Computational Science Initiative” 

    From Brookhaven National Lab

    Minerva, NVIDIA’s latest deep learning high-performance computing system, the DGX-2, now is part of Brookhaven’s Computational Science Initiative. Photo courtesy of NVIDIA

    November 6, 2018
    Peter Genzer
    genzer@bnl.gov
    (631) 344-3174 |

    Written by Charity Plata

    The Computational Science Initiative (CSI) at the U.S. Department of Energy’s Brookhaven National Laboratory now hosts one of the newest computing systems aimed at enhancing the speed and scale for conducting diverse scientific research: the NVIDIA® DGX-2™ Artificial Intelligence supercomputer.

    Designed to “take on the world’s most complex artificial intelligence challenges,” the NVIDIA DGX-2 at Brookhaven is one of the first available worldwide. At the Lab, the NVIDIA DGX-2, nicknamed “Minerva,” will serve as a user-accessible multipurpose machine focused on computer science research, machine learning, and data-intensive workloads.

    According to Adolfy Hoisie, who directs Brookhaven’s Computing for National Security Department, having the NVIDIA DGX-2’s compute power, which includes a 2-petaflops graphics processing unit (GPU) accelerator made possible by a scalable architecture built on the NVIDIA NVSwitch™ AI network fabric, will afford opportunities for diverse research pursuits with impact across the laboratory.

    In the area of systems architecture research, Hoisie expects that the NVIDIA DGX-2 will provide insights in evaluating the performance, power, and reliability of state-of-the-art computing technologies for various workloads.

    Because the NVIDIA DGX-2 specifically was designed to tackle the largest data sets and most computationally intensive and complex models, it also will play an important role in the Lab’s machine learning efforts. One such beneficiary will be the ExaLearn collaboration, an Exascale Computing Project co-design center featuring eight DOE national laboratories and led by CSI’s Deputy Director, Francis J. Alexander. The ExaLearn team primarily is developing machine learning software for exascale applications.

    The NVIDIA DGX-2 also will be engaged as part of CSI’s ongoing management, development, and discovery associated with the analysis and interpretation of high-volume, high-velocity heterogeneous scientific data.

    “We will expose the NVIDIA DGX-2 to data-intensive workloads for many programs, such as those of import to DOE science programs at the Lab’s Office of Science User Facilities—including the Relativistic Heavy Ion Collider, National Synchrotron Light Source II, and Center for Functional Nanomaterials—and to Department of Defense (DoD) data-intensive workloads of interest,” Hoisie explained. “Given significant bandwidth in and out of the system, we can pursue data analyses in multiple paradigms, for example, streaming data or fast access to vast amounts of data from Brookhaven Lab’s massive scientific databases. Such improvements will afford tremendous strides in data analyses within the Lab’s core high energy physics, nuclear physics, biological, atmospheric, and energy systems science areas and cryogenic technologies, as well as for specific research areas in computing sciences of interest to DOE and DoD.”

    CSI’s DGX-2 also will be a resource for NVIDIA as part of a collaboration. As research involving the system advances, its capability in impacting applications, speed to solutions, or even markers of its own overall performance will be shared between Brookhaven Lab and NVIDIA developers.

    DGX-2 is the newest addition to NVIDIA’s portfolio of AI supercomputers, which began with the DGX-1, introduced in 2016. The DGX-2 brings new innovations to AI, including the integration of 16 fully interconnected NVIDIA Tesla® Tensor Core V100 graphics processing units with 512 gigabytes of GPU memory.

    “We built the NVIDIA DGX-2 to solve the world’s most complex AI challenges, so we’re delighted that Brookhaven National Laboratory will put its innovations to use to further real-world science,” said Charlie Boyle, senior director of DGX Systems at NVIDIA. “The Lab’s researchers will be able to tap into the system’s 16 NVIDIA Tesla V100 Tensor Core GPUs—delivering two petaflops of computational performance—to help address opportunities of national importance.”

    For information about accessing the DGX-2 at Brookhaven Lab, please contact Adolfy Hoisie (ahoisie@bnl.gov).

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    BNL Campus

    BNL NSLS-II


    BNL NSLS II

    BNL RHIC Campus

    BNL/RHIC Star Detector

    BNL RHIC PHENIX

    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 9:37 pm on October 5, 2018 Permalink | Reply
    Tags: 'Choosy' Electronic Correlations Dominate Metallic State of Iron Superconductor, , BNL, , , HTS-high-temperature superconductors, , ,   

    From Brookhaven National Lab: “‘Choosy’ Electronic Correlations Dominate Metallic State of Iron Superconductor” 

    From Brookhaven National Lab

    October 3, 2018
    Ariana Tantillo
    atantillo@bnl.gov

    Finding could lead to a universal explanation of how two radically different types of materials—an insulator and a metal—can perfectly carry electrical current at relatively high temperatures.

    1
    Scientists discovered strong electronic correlations in certain orbitals, or energy shells, in the metallic state of the high-temperature superconductor iron selenide (FeSe). A schematic of the arrangement of the Se and Fe atoms is shown on the left; on the right is an image of the Se atoms in the termination layer of an FeSe crystal. Only the electron orbitals from the Fe atoms contribute to the orbital selectivity in the metallic state.

    Two families of high-temperature superconductors (HTS)—materials that can conduct electricity without energy loss at unusually high (but still quite cold) temperatures—may be more closely related than scientists originally thought.

    Beyond their layered crystal structures and the fact that they become superconducting when “doped” with atoms of other elements and cooled to a critical temperature, copper-based and iron-based HTS seemingly have little in common. After all, one material is normally an insulator (copper-based), and the other is a metal (iron-based). But a multi-institutional team of scientists has now presented new evidence suggesting that these radically different materials secretly share an important feature: strong electronic correlations. Such correlations occur when electrons move together in a highly coordinated way.

    “Theory has long predicted that strong electronic correlations can remain hidden in plain sight in a Hund’s metal,” said team member J.C. Seamus Davis, a physicist in the Condensed Matter Physics and Materials Science at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and the James Gilbert White Distinguished Professor in the Physical Sciences at Cornell University. “A Hund’s metal is a unique new type of electronic fluid in which the electrons from different orbitals, or energy shells, maintain very different degrees of correlation as they move through the material. By visualizing the orbital identity and correlation strength for different electrons in the metal iron selenide (FeSe), we discovered that orbital-selective strong correlations are present in this iron-based HTS.”

    It is yet to be determined if such correlations are characteristic of iron-based HTS in general. If proven to exist across both families of materials, they would provide the universal key ingredient in the recipe for high-temperature superconductivity. Finding this recipe has been a holy grail of condensed matter physics for decades, as it is key to developing more energy-efficient materials for medicine, electronics, transportation, and other applications.

    Experiment meets theory

    Since the discovery of iron-based HTS in 2008 (more than 20 years after that of copper-based HTS), scientists have been trying to understand the behavior of these unique materials. Confusion arose immediately because high-temperature superconductivity in copper-based materials emerges from a strongly correlated insulating state, but in iron-based HTS, it always emerges from a metallic state that lacks direct signatures of correlations. This distinction suggested that strong correlations were not essential—or perhaps even relevant—to high-temperature superconductivity. However, advanced theory soon provided another explanation. Because Fe-based materials have multiple active Fe orbitals, intense electronic correlations could exist but remain hidden due to orbital selectivity in the Hund’s metal state, yet still generate high-temperature superconductivity.

    In this study, recently described in Nature Materials, the team—including Brian Andersen of Copenhagen University, Peter Hirschfeld of the University of Florida, and Paul Canfield of DOE’s Ames National Laboratory—used a scanning tunneling microscope to image the quasiparticle interference of electrons in FeSe samples synthesized and characterized at Ames National Lab. Quasiparticle interference refers to the wave patterns that result when electrons are scattered due to atomic-scale defects—such as impurity atoms or vacancies—in the crystal lattice.

    2
    The spectroscopic imaging scanning tunneling microscope used for this study, in three different views.

    Spectroscopic imaging scanning tunneling microcopy can be used to visualize these interference patterns, which are characteristic of the microscopic behavior of electrons. In this technique, a single-atom probe moves back and forth very close to the sample’s surface in extremely tiny steps (as small as two trillionths of a meter) while measuring the amount of electrical current that is flowing between the single atom on the probe tip and the material, under an applied voltage.

    Their analysis of the interference patterns in FeSe revealed that the electronic correlations are orbitally selective—they depend on which orbital each electron comes from. By measuring the strength of the electronic correlations (i.e., amplitude of the quasiparticle interference patterns), they determined that some orbitals show very weak correlation, whereas others show very strong correlation.

    The next question to investigate is whether the orbital-selective electronic correlations are related to superconductivity. If the correlations act as a “glue” that binds electrons together into the pairs required to carry superconducting current—as is thought to happen in the copper-oxide HTS—a single picture of high-temperature superconductivity may emerge.

    Experimental studies were carried out by the former Center for Emergent Superconductivity, a DOE Energy Frontier Research Center at Brookhaven, and the research was supported by DOE’s Office of Science, the Moore Foundation’s Emergent Phenomena in Quantum Physics (EPiQS) Initiative, and a Lundbeckfond Fellowship.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    BNL Campus

    BNL NSLS-II


    BNL NSLS II

    BNL RHIC Campus

    BNL/RHIC Star Detector

    BNL RHIC PHENIX

    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 11:00 am on September 28, 2018 Permalink | Reply
    Tags: , BNL, , GRIK1, How a Molecular Signal Helps Plant Cells Decide When to Make Oil, How a sugar-signaling molecule helps regulate oil production in plant cells, KIN10, Microscale thermophoresis, The work could point to new ways to engineer plants to produce substantial amounts of oil for use as biofuels or in the production of other oil-based products, Trehalose 6-phosphate (T6P)   

    From Brookhaven National Lab: “How a Molecular Signal Helps Plant Cells Decide When to Make Oil” 

    From Brookhaven National Lab

    September 24, 2018
    Karen McNulty Walsh
    kmcnulty@bnl.gov
    (631) 344-8350

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

    Details of mechanism suggest new strategy for engineering plants to make more oil.

    1
    Jantana Keereetaweep, John Shanklin, and Zhiyang Zhai prepare samples for studying the biochemical pathways that regulate oil production in plants.

    A study at the U.S. Department of Energy’s Brookhaven National Laboratory identifies new details of how a sugar-signaling molecule helps regulate oil production in plant cells. As described in a paper appearing in the journal The Plant Cell, the work could point to new ways to engineer plants to produce substantial amounts of oil for use as biofuels or in the production of other oil-based products.

    The study builds on previous research led by Brookhaven Lab biochemist John Shanklin that established clear links between a protein complex that senses sugar levels in plant cells (specifically a subunit called KIN10) and another protein that serves as the “on switch” for oil production (WRINKLED1) [The Plant Cell]. Using this knowledge, Shanklin’s team recently demonstrated that they could use combinations of genetic variants that increase sugar accumulation in plant leaves to drive up oil production. The new work provides a more detailed understanding of the link between sugar signaling and oil production, identifying precisely which molecules regulate the balance and how.

    “If you were a cell, you’d want to know if you should be making new compounds or breaking existing ones down,” said Shanklin. “Making oil is demanding; you want to make it when you have lots of energy—which in cells is measured by the amount of sugar available. By understanding how the availability of sugar drives oil production, we hope to find ways to get plants to boost the priority of making oil.”

    The team’s earlier research revealed some key biochemical details of the sugar-oil balancing act. Specifically, they found that when sugar levels are low, the KIN10 portion of the sugar-sensing complex shuts off oil production by triggering degradation of the oil “on” switch (WRINKLED1). High sugar levels somehow prevented this degradation, leaving the on-switch protein stabilized to crank out oil. But the scientists didn’t understand exactly how.

    For the new paper, first authors Zhiyang Zhai and Jantana Keereetaweep led a detailed investigation to unravel how these molecular players interact to drive up oil production when sugar is abundant.

    The team used an emerging technique, called microscale thermophoresis, which uses fluorescent dyes and heat to precisely measure the strength of molecular interactions.

    “You label the molecules with a fluorescent dye and measure how they move away from a heat source,” Shanklin explained. “Then, if you add another molecule that binds to the labeled molecule, it changes the rate at which the labeled molecule moves away from the heat.”

    “Jan and Zhiyang’s rapid application of this novel technique to this tough research problem was key to solving it,” Shanklin said.

    3
    When a plant is low on sugar (left), a cascade of molecular interactions degrades (DEG) a protein (W) that turns on fatty acid synthesis (FAS). However, when sugar levels are high (right), key steps in this process are blocked, leaving the W protein intact to start fatty acid (oil) production. KEY: K = KIN10, G = GRIK1, P = phosphoryl group, W = WRINKLED1, FAS = fatty acid synthesis, DEG = degradation, T6P = trehalose 6-phosphate. Faded molecules and pathways are less active than those shown in bold colors.

    Among the substances included in the study was a molecule known as trehalose 6-phosphate (T6P), the levels of which rise and fall with those of sugar. The study revealed that T6P interacts directly with the KIN10 component of the sugar-sensing complex. And it showed how that binding interferes with KIN10’s ability to shut off oil biosynthesis.

    “By measuring the interactions among many different molecules, we determined that the sugar-signaling molecule, T6P, binds with KIN10 and interferes with its interaction with a previously unidentified intermediate in this process, known as GRIK1, which is needed for KIN10 to tag WRINKLED1 for destruction. This explains how the signal affects the chain of events and leads to increased oil production,” Shanklin said. “It’s not just sugar but the signaling molecule that rises and falls with sugar that inhibits the oil shut-off mechanism.”

    To put this knowledge into action to increase oil production, the scientists will need even more details. So, the next step will be to get a close-up look at the interaction of T6P with its target protein, KIN10, at Brookhaven’s National Synchrotron Light Source II (NSLS-II). This DOE Office of Science user facility produces extremely bright x-rays, which the team will use to reveal exactly how the interacting molecules fit together.

    “With NSLS-II at Brookhaven Lab, we are in the perfect place to bring this research to the next stage,” Shanklin said. “There are unique tools available at the Light Source that will allow us to add atomic-level details to the interactions that we discovered.”

    BNL NSLS-II

    And those details could point to ways to change the sequence of KIN10, T6P’s target protein, to mimic the effects of the interaction and modify the cell’s regulatory circuitry to prioritize the production of oil.

    This work was funded by the DOE Office of Science. John Lunn and Regina Feil from the Max Planck Institute of Molecular Plant Physiology in Potsdam-Golm, Germany, collaborated on this study.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    BNL Campus

    BNL NSLS-II


    BNL NSLS II

    BNL RHIC Campus

    BNL/RHIC Star Detector

    BNL RHIC PHENIX

    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 9:07 am on September 2, 2018 Permalink | Reply
    Tags: , , BNL, David Livoti,   

    From Brookhaven National Lab: “Meet David Livoti: Radiofrequency Technician in Collider-Accelerator Department” 

    From Brookhaven National Lab

    August 31, 2018
    Rebecca Wilkin
    rebeccalwilkin@gmail.com

    Former intern now employee helps to maintain radiofrequency systems for particle accelerators.

    1
    Former intern David Livoti is now a full-time employee in the radiofrequency (RF) group of the C-AD complex, where he’s part of a team of technicians that maintains RF systems for the Lab’s particle accelerators. No image credit.

    Growing up, David Livoti spent his summers working at libraries and garden centers near his home in Center Moriches. Then, in 2017, he landed his first internship just a few minutes down the road at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory, as a participant in the Office of Science’s Science Undergraduate Laboratory Internships (SULI) program. He quickly developed a passion for designing and studying the performance of electronics while building devices to measure snowfall amounts in Brookhaven’s Department of Environmental Science. One year later, Livoti is now helping to maintain acceleration systems for the Lab’s particle accelerators as a radiofrequency technician.

    “I like the atmosphere here at Brookhaven,” said Livoti, who graduated from Farmingdale State College last December with a dual degree in electrical and computer engineering. “I wanted to be in the research and design field, and I figured what better place to start a career than at a national laboratory where the most advanced research and design is done.”

    While interning under the direction of engineer Scott Smith, Livoti and fellow interns developed a machine that monitors snowfall accumulation—an improvement over the standard method of monitoring snowfall. That tedious task required taking manual measurements with a ruler every six hours!

    “The conventional method of measuring snow is archaic,” said Livoti, who completed all of the electronics and programming for the new device.

    The new device, developed in collaboration with the National Weather Service, has an electronic sensor that operates using sound waves, similar to the way sonar devices measure ocean depths. As snow accumulates, the sensor sends out sound waves to measure the change in distance between itself and the high point of accumulated snow piled up on a retractable table below. When the snow builds up to a certain point, the pre-programmed table tilts downward and the snow slides off, allowing the sensor to start measuring again, adding the additional accumulation to the running total.

    “This new, solar-powered device could help scientists determine snowfall rates more accurately, and it eliminates the task of taking manual measurements,” said Smith, who recently submitted the design for a patent. He noted that Livoti played a prominent role in building the device.

    “David has an incredible work ethic—he came to the lab early, stayed here late, and was relentless when it came to figuring out why something wasn’t working,” Smith said. “He’s also easy to get along with, and he has a great personality.”

    Hoping to continue his work with programming and electronics, Livoti applied for a position at the Lab after finishing his last semester of college. Within one month, he was hired as a technician in the radiofrequency (RF) group of the Collider-Accelerator Department (C-AD).

    The 23-year-old now works in the radiofrequency (RF) group of the C-AD complex, where he’s part of a team of technicians that maintains the RF systems. RF systems generate electric fields that control particles circulating in particle accelerators, including the Relativistic Heavy Ion Collider (RHIC)—a DOE Office of Science user facility for nuclear physics research that collides protons and/or heavy ions so scientists can study the building blocks of matter.

    “I enjoy maintaining the accelerators when they’re running, because it’s cool to see what the physicists are studying,” Livoti said. “But I also like when the accelerators are shut down, because that’s when the technicians get to experiment.”

    As part of the RF group, Livoti is assisting the lead engineers in maintaining and troubleshooting high power RF amplifiers and cavities that are integral parts of the C-AD complex. In addition, he is learning new technologies and conducting tests on solid-state and vacuum-tube amplifiers, as well as learning to program and use devices that control power supplies and monitor the status of other accelerator subcomponents.

    Livoti plans to continue this research and someday obtain a master’s degree in electrical engineering. When he isn’t busy maintaining and testing RF systems, he spends his time snowboarding and playing softball in the Lab’s league.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    BNL Campus

    BNL NSLS-II


    BNL NSLS II

    BNL RHIC Campus

    BNL/RHIC Star Detector

    BNL RHIC PHENIX

    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 8:09 pm on August 23, 2018 Permalink | Reply
    Tags: 3-D x-ray imaging that can visualize bulky materials in great detail, , BNL, called Multilayer Laue lenses (MLLs), HXN’s special optics, Novel X-Ray Optics Boost Imaging Capabilities at NSLS-II, ,   

    From Brookhaven National Lab: “Novel X-Ray Optics Boost Imaging Capabilities at NSLS-II” 

    From Brookhaven National Lab

    August 23, 2018
    Rebecca Wilkin
    rebeccalwilkin@gmail.com

    Brookhaven Lab scientists capture high-resolution, 3-D images of thick materials more efficiently than ever before.

    1
    NSLS-II scientist Hande Öztürk stands next to the Hard X-ray Nanoprobe (HXN) beamline, where her research team developed the new x-ray imaging technique. No photo credit.

    Scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory have developed a new approach to 3-D x-ray imaging that can visualize bulky materials in great detail—an impossible task with conventional imaging methods. The novel technique could help scientists unlock clues about the structural information of countless materials, from batteries to biological systems.

    The scientists developed their approach at Brookhaven’s National Synchrotron Light Source II (NSLS-II)—a DOE Office of Science User Facility where scientists use ultra-bright x-rays to reveal details at the nanoscale. The team is located at NSLS-II’s Hard X-ray Nanoprobe (HXN) beamline, an experimental station that uses advanced lenses to offer world-leading resolution, all the way down to 10 nanometers—about one ten-thousandth the diameter of a human hair.

    HXN produces remarkably high-resolution images that can provide scientists with a comprehensive view of different material properties in 2-D and 3-D. The beamline also has a unique combination of in situ and operando capabilities—methods of studying materials in real-life operating conditions. However, scientists who use x-ray microscopes have been restricted by the size and thickness of the materials they can study.

    “The x-ray imaging community is still facing major challenges in fully exploiting the potential of beamlines like HXN, especially for obtaining high-resolution details from thick samples,” said Yong Chu, lead beamline scientist at HXN. “Obtaining quality, high-resolution images can become challenging when a material is thick—that is, thicker than the x-ray optics’ depth of focus.”

    Now, scientists at HXN have developed an efficient approach to studying thick samples without sacrificing the excellent resolution that HXN provides. They describe their approach in a paper published in the journal Optica.

    “The ultimate goal of our research is to break the technical barrier imposed on sample thickness and develop a new way of performing 3-D imaging—one that involves mathematically slicing through the sample,” said Xiaojing Huang, a scientist at HXN and a co-author of the paper.

    2
    The research team is pictured at the HXN workstation. Standing, from left to right, are Xiaojing Huang, Hanfei Yan, Evgeny Nazaretski, Yong Chu, Mingyuan Ge, and Zhihua Dong. Sitting, from left to right, are Hande Öztürk and Meifeng Lin. Not pictured: Ian Robinson.

    The conventional method of obtaining a 3-D image involves collecting and combining a series of 2-D images. To obtain these 2-D images, the scientists typically rotate the sample 180 degrees; however, large samples cannot easily rotate within the limited space of typical x-ray microscopes. This limitation, in addition to the challenge of imaging thick samples, makes it nearly impossible to reconstruct a 3-D image with high resolution.

    “Instead of collecting a series of 2-D projections by rotating the sample, we simply ‘slice’ the thick material into a series of thin layers,” said lead author Hande Öztürk. “This slicing process is carried out mathematically without physically modifying the sample.”

    Their technique benefits from HXN’s special optics, called Multilayer Laue lenses (MLLs), which are engineered to focus x-rays into a tiny point. These lenses create favorable conditions for studying thinner slices of thick materials, while also reducing the measurement time.

    “HXN’s unique MLLs have a high focusing efficiency, so we can spend much less time collecting the signal we need,” said Hanfei Yan, a scientist at HXN and a co-author of the paper.

    By combining the MLL optics and the multi-slice approach, the HXN scientists were able to visualize two layers of nanoparticles separated by only 10 microns—about one tenth the diameter of a human hair—and with a resolution 100 times smaller. Additionally, the method significantly cut down the time needed to obtain a single image.

    “This development provides an exciting opportunity to perform 3-D imaging on samples that are very difficult to image with conventional methods—for example, a battery with a complicated electrochemical cell,” said Chu. He added that this approach could be very useful for a wide variety of future research applications.

    This study was supported by Brookhaven Lab’s Laboratory Directed Research and Development program. Operations at NSLS-II are supported by DOE’s Office of Science.

    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 1:36 pm on August 17, 2018 Permalink | Reply
    Tags: , BNL, , Photo study   

    From Brookhaven National Laboratory: “The superhot collisions at the Relativistic Heavy Ion Collider ” Photo Study 

    From Brookhaven National Laboratory

    1
    The superhot collisions at the Relativistic Heavy Ion Collider melt protons and neutrons, freeing their inner building blocks, so scientists can study the force that holds them together.

    2
    This new technique literally pushes x-rays to the edge to help draw the nanoworld into greater focus. This rendering shows a high-intensity x-ray beam striking and traveling through an ultra-thin material. The resulting x-ray scattering—those blue and white ripples—is much less distorted than in other methods, which means superior images of nanoscale structures ranging from proteins to catalysts. Get the full story right here: http://1.usa.gov/Y5GY7M

    3
    March 29, 2013 Photo of the Week: Laser Chamber

    This is one of the vacuum chambers where we grow cutting-edge iron-based superconductors that could advance everything from wind turbines to particle accelerators. Our researchers use a technique called pulsed-laser deposition to fabricate superconducting thin films right here– a high-power laser vaporizes materials that are then re-collected in ultra-precise new configurations.

    5
    April 12, 2013 Photo of the Week: Crystal Garden

    Many of the materials we make here at Brookhaven are much too small for traditional tools — good luck trying to hammer atoms into place or screw nanoscale films together. So when we can’t build materials, we grow them.

    The glowing chamber above, an infrared image furnace, is used to grow ultra-precise superconducting crystals. Infrared light focuses onto a rod, melting it at temperatures of about 4,000 degrees Fahrenheit. Under just the right conditions, that liquefied material recrystallizes as a single uniform structure. One of our physicists, Genda Gu, actually pioneered techniques that grow some of the largest single-crystal high-temperature superconductors in the world. And hey, it only takes him a month of gold-assisted gardening to grow each one just right.

    6
    May 3, 2013 Photo of the Week: Tunneling Technology

    The sustainable energy of tomorrow requires custom-designed catalysts to pry power from different fuel sources. To advance this essential technology, our scientists use instruments such as this scanning tunneling microscope to reveal the atomic-scale building blocks and processes that point the way to new breakthroughs.

    Many many more at the full article.

    See the full article here.

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    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 12:05 pm on August 10, 2018 Permalink | Reply
    Tags: , BNL, , Lining Up the Surprising Behaviors of a Superconductor with One of the World's Strongest Magnets, , , National High Magnetic Field Laboratory, Pulsed Field Facility at Los Alamos National Laboratory,   

    From Brookhaven National Lab: “Lining Up the Surprising Behaviors of a Superconductor with One of the World’s Strongest Magnets” 

    From Brookhaven National Lab

    August 8, 2018

    atantillo@bnl.gov
    Ariana Tantillo
    (631) 344-2347

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

    Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way—a finding that could help direct the search for materials that can perfectly conduct electricity at room temperature.

    1
    (Clockwise from back left) Brookhaven Lab physicists Ivan Bozovic, Anthony Bollinger, and Jie Wu, and postdoctoral researcher Xi He used the molecular beam epitaxy system seen above to synthesize perfect single-crystal thin films made of lanthanum, strontium, oxygen, and copper (LSCO). They brought these superconducting films to the National High Magnetic Field Laboratory to see how the electrical resistance of LSCO in its “strange” metallic state changes under extremely strong magnetic fields.

    What happens when really powerful magnets—capable of producing magnetic fields nearly two million times stronger than Earth’s—are applied to materials that have a “super” ability to conduct electricity when chilled by liquid nitrogen? A team of scientists set out to answer this question in one such superconductor made of the elements lanthanum, strontium, copper, and oxygen (LSCO). They discovered that the electrical resistance of this copper-oxide compound, or cuprate, changes in an unusual way when very high magnetic fields suppress its superconductivity at low temperatures.

    “The most pressing problem in condensed matter physics is understanding the mechanism of superconductivity in cuprates because at ambient pressure they become superconducting at the highest temperature of any currently known material,” said physicist Ivan Bozovic, who leads the Oxide Molecular Beam Epitaxy Group at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and who is a coauthor of the Aug. 3 Science paper reporting the discovery. “This new result—that the electrical resistivity of LSCO scales linearly with magnetic field strength at low temperatures—provides further evidence that high-temperature superconductors do not behave like ordinary metals or superconductors. Once we can come up with a theory to explain their unusual behavior, we will know whether and where to search for superconductors that can carry large amounts of electrical current at higher temperatures, and perhaps even at room temperature.”

    Cuprates such as LSCO are normally insulators. Only when they are cooled to some hundred degrees below zero and the concentrations of their chemical composition are modified (a process called doping) to a make them metallic can their mobile electrons pair up to form a “superfluid” that flows without resistance. Scientists hope that understanding how cuprates achieve this amazing feat will enable them to develop room-temperature superconductors, which would make energy generation and delivery significantly more efficient and less expensive.

    In 2016, Bozovic’s group reported that LSCO’s superconducting state is nothing like the one explained by the generally accepted theory of classical superconductivity; it depends on the number of electron pairs in a given volume rather than the strength of the electron pairing interaction. In a follow-up experiment published the following year, they obtained another puzzling result: when LSCO is in its non-superconducting (normal, or “metallic”) state, its electrons do not behave as a liquid, as would be expected from the standard understanding of metals.

    “The condensed matter physics community has been divided about this most basic question: do the behaviors of cuprates fall within existing theories for superconductors and metals, or are there profoundly different physical principles involved?” said Bozovic.

    Continuing this comprehensive multipart study that began in 2005, Bozovic’s group and collaborators have now found additional evidence to support the latter idea that the existing theories are incomplete. In other words, it is possible that these theories do not encompass every known material. Maybe there are two different types of metals and superconductors, for example.

    “This study points to another property of the strange metallic state in the cuprates that is not typical of metals: linear magnetoresistance at very high magnetic fields,” said Bozovic. “At low temperatures where the superconducting state is suppressed, the electrical resistivity of LSCO scales linearly (in a straight line) with the magnetic field; in metals, this relationship is quadratic (forms a parabola).”

    2
    This composite image offers a glimpse inside the custom-designed molecular beam epitaxy system that the Brookhaven physicists use to create single-crystal thin films for studying the properties of superconducting cuprates.

    In order to study magneto resistance, Bozovic and group members Anthony Bollinger, Xi He, and Jie Wu first had to create flawless single-crystal thin films of LSCO near its optimal doping level. They used a technique called molecular beam epitaxy, in which separate beams containing atoms of the different chemical elements are fired onto a heated single-crystal substrate. When the atoms land on the substrate surface, they condense and slowly grow into ultra-thin layers, building a single atomic layer at a time. The growth of the crystal occurs in highly controlled conditions of ultra-high vacuum to ensure that the samples do not get contaminated.

    “Brookhaven Lab’s key contribution to this study is this material synthesis platform,” said Bozovic. “It allows us to tailor the chemical composition of the films for different studies and provides the foundation for us to observe the true properties of superconducting materials, as opposed to properties induced by sample defects or impurities.”

    The scientists then patterned the thin films onto strips containing voltage leads so that the amount of electrical current flowing through LSCO under an applied magnetic field could be measured.

    They conducted initial magneto resistivity measurements with two 9 Tesla magnets at Brookhaven Lab—for reference, the strength of the magnets used in today’s magnetic resonance imaging (MRI) machines are typically up to 3 Tesla. Then, they brought their best samples (those with the best structural and transport qualities) to the Pulsed Field Facility. Located at DOE’s Los Alamos National Laboratory, this international user facility is part of the National High Magnetic Field Laboratory, which houses some of the strongest magnets in the world. Scientists at the Pulsed Field Facility placed the samples in an 80 Tesla pulsed magnet, powered by quick pulses, or shots, of electrical current. The magnet produces such large magnetic fields that it cannot be energized for more than a very short period of time (microseconds to a fraction of a second) without destroying itself.

    “This large magnet, which is the size of a room and draws the electricity of a small city, is the only such installation on this continent,” said Bozovic. “We only get access to it once a year if we are lucky, so we chose our best samples to study.”

    In October, the scientists will get access to a stronger (90 Tesla) magnet, which they will use to collect additional magneto resistance data to see if the linear relationship still holds.

    3
    An example of a typical device that the scientists use to measure electrical resistivity as a function of temperature and magnetic field. The scientists grew the film via atomic layer-by-layer molecular beam epitaxy, patterned it into a device, and wire bonded it to a chip carrier.

    “While I do not expect to see something different, this higher field strength will allow us to expand the range of doping levels at which we can suppress superconductivity,” said Bozovic. “Collecting more data over a broader range of chemical compositions will help theorists formulate the ultimate theory of high-temperature superconductivity in cuprates.”

    In the next year, Bozovic and the other physicists will collaborate with theorists to interpret the experimental data.

    “It appears that the strongly correlated motion of electrons is behind the linear relationship we observed,” said Bozovic. “There are various ideas of how to explain this behavior, but at this point, I would not single out any of them.”

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

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    BNL RHIC PHENIX

    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 12:18 pm on August 3, 2018 Permalink | Reply
    Tags: , BNL, Gears in a quantum clock, , , X-ray scattering,   

    From Brookhaven Lab: “New Magnetic Materials Overcome Key Barrier to Spintronic Devices” 

    From Brookhaven National Lab

    August 1, 2018
    Justin Eure
    justin.eure@gmail.com

    Custom-engineered structure enables unprecedented control and efficiency in otherwise impervious antiferromagnetic materials.

    1
    Brookhaven scientists Derek Meyers (left) and Mark Dean (right) using their x-ray diffractometer to characterize the atomic structure of the samples for the experiment.

    Consider the classic, permanent magnet: it both clings to the refrigerator and drives data storage in most devices. But another kind of impervious magnetism hides deep within many materials—a phenomenon called antiferromagnetism (AFM)—and is nearly imperceptible beyond the atomic scale.

    Now, a team of scientists just developed an unprecedented material that cracks open this hermetic magnetism, confirming a decades-old theory and creating new engineering possibilities. The team, led by the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and the University of Tennessee, designed AFM materials with spin—the quantum mechanism behind all magnetism—that can be easily controlled with minimal energy.

    “Material synthesis finally caught up to theory, and we found a way around the most prohibitive quantum quirks of exploiting antiferromagnetism,” said Brookhaven Lab physicist and study corresponding author Mark Dean. “This work dives deeper into the underpinnings of magnetism and creates new possibilities for spin-based technologies.”

    The results, published this summer in Nature Physics, could dramatically enhance the emerging field of spintronics, where information is coded into the directional spin of electrons.

    “The real surprise was just how well this synthetic material functioned right out of the gate,” said coauthor and Brookhaven Lab scientist Derek Meyers. “Not only can we manipulate this remarkable spin, but we can do it with extreme efficiency.”

    Twisting electron spins

    The spin orientation of electrons within atoms and can be visualized as simple arrows pointing in well-defined directions.

    “In ferromagnets, these spins are all aligned,” said University of Tennessee professor and corresponding author Jian Liu. “They all point up or down, creating an external magnetic effect—like refrigerator magnets—that can be flipped when an external field is applied.”

    This flipping process powers the writing of digital information on most data storage devices, among other things.

    “Antiferromagnets are much stranger,” Meyers said. “Every arrow points in the opposite direction of its nearest neighbor, alternating up-down-up-down across the material. And it stays synchronized, such that one flip reverses all the others. That means, essentially, they all cancel each other out.”

    This perfect balance makes AFM spin notoriously impervious to manipulation, requiring too much energy to make the process useful. So the scientists introduced a little imperfection.

    “If we tilt, or cant, the spins, we create asymmetry and make the material more susceptible to influence,” Dean said. “External magnets can couple with the spin. But prior to this work, there was a built-in compromise to this approach.”

    While the canted spin can “feel” magnetic fields, the directional freedom is lost—the spins can no longer change direction.

    Gears in a quantum clock

    Imagine adjacent electrons as gears in a clock: the teeth all fit together to move in tandem and preserve precise relationships. Tilting the spin realigns those gears, almost as if they abruptly began to rotate in opposite directions and locked in place. How, then, to set those gears back in motion?

    “We followed a long-standing theory to create an unprecedented material that both cants the spin and keeps it free to rotate, which we would call preserving isotropy,” said first author Lin Hao of the University of Tennessee. “To do this, we designed a structure that cancels out those competing anisotropies, or directional asymmetries.”

    In a way, they built another gear into their antiferromagnetic clock. The extra gear slots in between the jammed electron spins, giving them a balance and space that would never naturally occur. The “gear” is actually a hidden symmetry called SU(2), a mathematical term describing the isotropic freedom.

    Layered crystalline lattice

    “The extreme sophistication of two-dimensional materials synthesis made this possible,” Liu said. “We grew a crystalline lattice with fully customized geometries to prevent the spins from locking—this is engineering with almost quantum precision.”

    The team used pulsed laser deposition to create a lattice composed of strontium, iridium, titanium, and oxygen. In this way, atomically thin layers could be stacked in different configurations to induce artificial and much desired properties.

    In this work, the team exploited special “gearing” properties of the iridium oxide layers in which the spins can be tilted, but remain free to respond to an applied magnetic field.

    The collaboration turned to the Advanced Photon Source (APS)—a DOE Office of Science User Facility at DOE’s Argonne National Laboratory—to confirm the crystal structure of the material. Using advanced resonant x-ray diffraction, the scientists revealed details of both the lattice and the electron configuration.


    ANL/APS

    “Because of the precision possible at the APS, we were able to see the fruits of the difficult synthesis process,” Meyers said. “We saw the precise layered structure we wanted, but the real test was in the magnetic function.”

    Again turning to APS, the team used x-ray scattering to measure the antiferromagnetic order, the alignment of the spins within the material.

    “We were pleased to see our canted spins retain the freedom of motion we expected,” Dean said. “It’s rare and thrilling to see things come together so seamlessly. And crucially, we proved that manipulating that AFM spin required very little energy—a must for spintronic applications.”

    Toward superior storage

    Traditional magnetic devices have an intrinsic limit: packed too closely together, ferromagnetic materials affect each other. This translates into a functional cap on data density beyond which the spins become corrupted. However, AFM materials—or discrete AFM crystals in this instance—exert no external influence.

    “We can, in theory, pack much more information into devices by manipulating antiferromagnetic spin,” Dean said. “That’s part of the promise of spintronics.”

    The combination of low energy input—think efficient writing of data—and density make the new material an ideal candidate for investment.

    “The obstacle right now has to do with scale,” Liu said. “This is a first-of-its-kind material, so no industrial-scale process exists. But this is how it starts, and the demand for this kind of functionality might rapidly move this innovation into applications.”

    Additional collaborating institutions include Charles University in Prague.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

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    BNL RHIC PHENIX

    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 2:17 pm on July 14, 2018 Permalink | Reply
    Tags: , BNL, , , ,   

    From Brookhaven via Fermilab : “Theorists Publish Highest-Precision Prediction of Muon Magnetic Anomaly 

    From Brookhaven Lab

    via

    FNAL II photo

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

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

    7.12.18
    Karen McNulty Walsh
    kmcnulty@bnl.gov
    (631) 344-8350

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

    Latest calculation based on how subatomic muons interact with all known particles comes out just in time for comparison with precision measurements at new “Muon g-2” experiment.

    FNAL Muon G-2 studio at FNAL

    Theoretical physicists at the U.S. Department of Energy’s (DOE’s) Brookhaven National Laboratory and their collaborators have just released the most precise prediction of how subatomic particles called muons—heavy cousins of electrons—“wobble” off their path in a powerful magnetic field. The calculations take into account how muons interact with all other known particles through three of nature’s four fundamental forces (the strong nuclear force, the weak nuclear force, and electromagnetism) while reducing the greatest source of uncertainty in the prediction. The results, published in Physical Review Letters as an Editors’ Suggestion, come just in time for the start of a new experiment measuring the wobble now underway at DOE’s Fermi National Accelerator Laboratory (Fermilab).

    A version of this experiment, known as “Muon g-2,” ran at Brookhaven Lab in the late 1990s and early 2000s, producing a series of results indicating a discrepancy between the measurement and the prediction. Though not quite significant enough to declare a discovery, those results hinted that new, yet-to-be discovered particles might be affecting the muons’ behavior. The new experiment at Fermilab, combined with the higher-precision calculations, will provide a more stringent test of the Standard Model, the reigning theory of particle physics. If the discrepancy between experiment and theory still stands, it could point to the existence of new particles.

    “If there’s another particle that pops into existence and interacts with the muon before it interacts with the magnetic field, that could explain the difference between the experimental measurement and our theoretical prediction,” said Christoph Lehner, one of the Brookhaven Lab theorists who led the latest calculations. “That could be a particle we’ve never seen before, one not included in the Standard Model.”

    Finding new particles beyond those already cataloged by the Standard Model has long been a quest for particle physicists. Spotting signs of a new particle affecting the behavior of muons could guide the design of experiments to search for direct evidence of such particles, said Taku Izubuchi, another leader of Brookhaven’s theoretical physics team.

    “It would be a strong hint and would give us some information about what this unknown particle might be—something about what the new physics is, how this particle affects the muon, and what to look for,” Izubuchi said.

    The muon anomaly

    The Muon g-2 experiment measures what happens as muons circulate through a 50-foot-diameter electromagnet storage ring. The muons, which have intrinsic magnetism and spin (sort of like spinning toy tops), start off with their spins aligned with their direction of motion. But as the particles go ’round and ’round the magnet racetrack, they interact with the storage ring’s magnetic field and also with a zoo of virtual particles that pop in and out of existence within the vacuum. This all happens in accordance with the rules of the Standard Model, which describes all the known particles and their interactions, so the mathematical calculations based on that theory can precisely predict how the muons’ alignment should precess, or “wobble” away from their spin-aligned path. Sensors surrounding the magnet measure the precession with extreme precision so the physicists can test whether the theory-generated prediction is correct.

    Both the experiments measuring this quantity and the theoretical predictions have become more and more precise, tracing a journey across the country with input from many famous physicists.

    A race and collaboration for precision

    “There is a race of sorts between experiment and theory,” Lehner said. “Getting a more precise experimental measurement allows you to test more and more details of the theory. And then you also need to control the theory calculation at higher and higher levels to match the precision of the experiment.”

    With lingering hints of a new discovery from the Brookhaven experiment—but also the possibility that the discrepancy would disappear with higher precision measurements—physicists pushed for the opportunity to continue the search using a higher-intensity muon beam at Fermilab. In the summer of 2013, the two labs teamed up to transport Brookhaven’s storage ring via an epic land-and-sea journey from Long Island to Illinois. After tuning up the magnet and making a slew of other adjustments, the team at Fermilab recently started taking new data.

    Meanwhile, the theorists have been refining their calculations to match the precision of the new experiment.

    “There have been many heroic physicists who have spent a huge part of their lives on this problem,” Izubuchi said. “What we are measuring is a tiny deviation from the expected behavior of these particles—like measuring a half a millimeter deviation in the flight distance between New York and Los Angeles! But everything about the fate of the laws of physics depends on that difference. So, it sounds small, but it’s really important. You have to understand everything to explain this deviation,” he said.

    The path to reduced uncertainty

    By “everything” he means how all the known particles of the Standard Model affect muons via nature’s four fundamental forces—gravity, electromagnetism, the strong nuclear force, and the electroweak force. Fortunately, the electroweak contributions are well understood, and gravity is thought to play a currently negligible role in the muon’s wobble. So the latest effort—led by the Brookhaven team with contributions from the RBC Collaboration (made up of physicists from the RIKEN BNL Research Center, Brookhaven Lab, and Columbia University) and the UKQCD collaboration—focuses specifically on the combined effects of the strong force (described by a theory called quantum chromodynamics, or QCD) and electromagnetism.

    “This has been the least understood part of the theory, and therefore the greatest source of uncertainty in the overall prediction. Our paper is the most successful attempt to reduce those uncertainties, the last piece at the so-called ‘precision frontier’—the one that improves the overall theory calculation,” Lehner said.

    The mathematical calculations are extremely complex—from laying out all the possible particle interactions and understanding their individual contributions to calculating their combined effects. To tackle the challenge, the physicists used a method known as Lattice QCD, originally developed at Brookhaven Lab, and powerful supercomputers. The largest was the Leadership Computing Facility at Argonne National Laboratory, a DOE Office of Science user facility, while smaller supercomputers hosted by Brookhaven’s Computational Sciences Initiative (CSI)—including one machine purchased with funds from RIKEN, CSI, and Lehner’s DOE Early Career Research Award funding—were also essential to the final result.

    “One of the reasons for our increased precision was our new methodology, which combined the most precise data from supercomputer simulations with related experimental measurements,” Lehner noted.

    Other groups have also been working on this problem, he said, and the entire community of about 100 theoretical physicists will be discussing all of the results in a series of workshops over the next several months to come to agreement on the value they will use to compare with the Fermilab measurements.

    “We’re really looking forward to Fermilab’s results,” Izubuchi said, echoing the anticipation of all the physicists who have come before him in this quest to understand the secrets of the universe.

    The theoretical work at Brookhaven was funded by the DOE Office of Science, RIKEN, and Lehner’s Early Career Research Award.

    The Muon g-2 experiment at Fermilab is supported by DOE’s Office of Science and the National Science Foundation. The Muon g-2 collaboration has almost 200 scientists and engineers from 34 institutions in seven countries. Learn more about the new Muon g-2 experiment or take a virtual tour.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    BNL Campus

    BNL RHIC Campus

    BNL/RHIC Star Detector

    BNL RHIC PHENIX

    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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