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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

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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 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 .


    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 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

    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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  • 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

    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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  • 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

    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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  • 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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  • richardmitnick 1:25 pm on June 22, 2018 Permalink | Reply
    Tags: , , BNL, , , , ,   

    From Brookhaven Lab: “Upgrades to ATLAS and LHC Magnets for Run 2 and Beyond” 

    From Brookhaven Lab

    6.22.18

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

    The following news release was issued by CERN, the European Organization for Nuclear Research, home to the Large Hadron Collider (LHC). Scientists from the U.S. Department of Energy’s Brookhaven National Laboratory play multiple roles in the research at the LHC and are making major contributions to the high-luminosity upgrade described in this news release, including the development of new niobium tin superconducting magnets that will enable significantly higher collision rates; new particle tracking and signal readout systems for the ATLAS experiment that will allow scientists to capture and analyze the most significant details from vastly larger data sets; and increases in computing capacity devoted to analyzing and sharing that data with scientists around the world. Brookhaven Lab also hosts the Project Office for the U.S. contribution to the HL-LHC detector upgrades of the ATLAS experiment. For more information about Brookhaven’s roles in the high-luminosity upgrade or to speak with a Brookhaven/LHC scientist, contact Karen McNulty Walsh, (631) 344-8350, kmcnulty@bnl.gov.

    Brookhaven physicists play critical roles in LHC restart and plans for the future of particle physics.

    1
    The ATLAS detector at the Large Hadron Collider, an experiment with large involvement from physicists at Brookhaven National Laboratory. Image credit: CERN

    July 6, 2015

    At the beginning of June, the Large Hadron Collider at CERN, the European research facility, began smashing together protons once again. The high-energy particle collisions taking place deep underground along the border between Switzerland and France are intended to allow physicists to probe the furthest edges of our knowledge of the universe and its tiniest building blocks.

    The Large Hadron Collider returns to operations after a two-year offline period, Long Shutdown 1, which allowed thousands of physicists worldwide to undertake crucial upgrades to the already cutting-edge particle accelerator. The LHC now begins its second multi-year operating period, Run 2, which will take the collider through 2018 with collision energies nearly double those of Run 1. In other words, Run 2 will nearly double the energies that allowed researchers to detect the long-sought Higgs Boson in 2012.

    CERN CMS Higgs Event

    CERN ATLAS Higgs Event

    The U.S. Department of Energy’s Brookhaven National Laboratory is a crucial player in the physics program at the Large Hadron Collider, in particular as the U.S. host laboratory for the pivotal ATLAS experiment, one of the two large experiments that discovered the Higgs. Physicists at Brookhaven were busy throughout Long Shutdown 1, undertaking projects designed to maximize the LHC’s chances of detecting rare new physics as the collider reaches into a previous unexplored subatomic frontier.

    While the technology needed to produce a new particle is a marvel on its own terms, equally remarkable is everything the team at ATLAS and other experiments must do to detect these potentially world-changing discoveries. Because the production of such particles is a rare phenomenon, it isn’t enough to just be able to smash one proton into another. The LHC needs to be able to collide proton bunches, each bunch consisting of hundreds of billions of particles, every 50 nanoseconds—eventually rising to every 25 nanoseconds in Run 2—and be ready to sort through the colossal amounts of data that all those collisions produce.

    It is with those interwoven challenges—maximizing the number of collisions within the LHC, capturing the details of potentially noteworthy collisions, and then managing the gargantuan amount of data those collisions produce—that scientists at Brookhaven National Laboratory are making their mark on the Large Hadron Collider and its search for new physics—and not just for the current Run 2, but looking forward to the long-term future operation of the collider.

    Restarting the Large Hadron Collider

    LHC

    CERN map


    CERN LHC Tunnel

    CERN LHC particles

    THE FOUR MAJOR PROJECT COLLABORATIONS

    ATLAS
    CERN ATLAS New

    ALICE
    CERN ALICE New

    CMS
    CERN CMS New

    LHCb
    CERN LHCb New II

    2
    Brookhaven physicist Srini Rajagopalan, operation program manager for U.S. ATLAS, works to keep manageable the colossal amounts of data that are generated by the Large Hadron Collider and sent to Brookhaven’s RHIC and ATLAS Computing Facility.

    The Large Hadron Collider is the largest single machine in the world, so it’s tempting to think of its scale just in terms of its immense size. The twin beamlines of the particle accelerator sit about 300 to 600 feet underground in a circular tunnel more than 17 miles around. Over 1,600 magnets, each weighing more than 25 tons, are required to keep the beams of protons focused and on the correct paths, and nearly 100 tons of liquid helium is necessary to keep the magnets operating at temperatures barely above absolute zero. Then there are the detectors, each of which stand several stories high.

    But the scale of the LHC extends not just in space, but in time as well. A machine of this size and complexity doesn’t just switch on or off with the push of a button, and even relatively simple maintenance can require weeks, if not months, to perform. That’s why the LHC recently completed Long Shutdown 1, a two-year offline period in which physicists undertook the necessary repairs and upgrades to get the collider ready for the next three years of near-continuous operation. As the U.S. host laboratory for the ATLAS experiment, Brookhaven National Laboratory was pivotal in upgrading and improving one of the cornerstones of the LHC apparatus.

    “After having run for three years, the detector needs to be serviced much like your car,” said Brookhaven physicist Srini Rajagopalan, operation program manager for U.S. ATLAS. “Gas leaks crop up that need to be fixed. Power supplies, electronic boards and several other components need to be repaired or replaced. Hence a significant amount of detector consolidation work occurs during the shutdown to ensure an optimal working detector when beam returns.”

    Beyond these vital repairs, the major goal of the upgrade work during Long Shutdown 1 was to increase the LHC’s center of mass energies from the previous 8 trillion electron volts (TeV) to 13 TeV, near the operational maximum of 14 TeV.

    “Upgrading the energy means you’re able to probe much higher mass ranges, and you have access to new particles that might be substantially heavier,” said Rajagopalan. “If you have a very heavy particle that cannot be produced, it doesn’t matter how much data you collect, you just cannot reach that. That’s why it was very important to go from 8 to 13 TeV. Doubling the energy allows us to access the new physics much more easily.”

    As the LHC probes higher and higher energies, the phenomena that the researchers hope to observe will happen more and more rarely, meaning the particle beams need to create many more collisions than they did before. Beyond this increase in collision rates, or luminosity, however, the entire infrastructure of data collection and management has to evolve to deal with the vastly increased volume of information the LHC can now produce.

    “Much of the software had to be evolved or rewritten,” said Rajagopalan, “from patches and fixes that are more or less routine software maintenance to implementing new algorithms and installing new complex data management systems capable of handling the higher luminosity and collision rates.”

    Making More Powerful Magnets

    3
    Brookhaven physicist Peter Wanderer, head of the laboratory’s Superconducting Magnet Division, stands in front of the oven in which niobium tin is made into a superconductor.

    The Large Hadron Collider works by accelerating twin beams of protons to speeds close to that of light. The two beams, traveling in opposite directions along the path of the collider, both contain many bunches of protons, with each bunch containing about 100 billion protons. When the bunches of protons meet, not all of the protons inside of them are going to interact and only a tiny fraction of the colliding bunches are likely to yield potentially interesting physics. As such, it’s absolutely vital to control those beams to maximize the chances of useful collisions occurring.

    The best way to achieve that and the desired increase in luminosity—both during the current Run 2, and looking ahead to the long-term future of the LHC—is to tighten the focus of the beam. The more tightly packed protons are, the more likely they’ll smash into each other. This means working with the main tool that controls the beam inside the accelerator: the magnets.

    FNAL magnets such as this one, which is mounted on a test stand at Fermilab, for the High-Luminosity LHC Photo Reidar Hahn

    “Most of the length of the circumference along a circular machine like the LHC is taken up with a regular sequence of magnets,” said Peter Wanderer, head of Brookhaven Lab’s Superconducting Magnet Division, which made some of the magnets for the current LHC configuration and is working on new designs for future upgrades. “The job of these magnets is to bend the proton beams around to the next point or region where you can do something useful with them, like produce collisions, without letting the beam get larger.”

    A beam of protons is a bunch of positively charged particles that all repel one another, so they want to move apart, he explained. So physicists use the magnetic fields to keep the particles from being able to move away from the desired path.

    “You insert different kinds of magnets, different sequences of magnets, in order to make the beams as small as possible, to get the most collisions possible when the beams collide,” Wanderer said.

    The magnets currently in use in the LHC are made of the superconducting material niobium titanium (NbTi). When the electromagnets are cooled in liquid helium to temperatures of about 4 Kelvin (-452.5 degrees Fahrenheit), they lose all electric resistance and are able to achieve a much higher current density compared with a conventional conductor like copper. A magnetic field gets stronger as its current is more densely packed, meaning a superconductor can produce a much stronger field over a smaller radius than copper.

    But there’s an upper limit to how high a field the present niobium titanium superconductors can reach. So Wanderer and his team at Brookhaven have been part of a decade-long project to refine the next generation of superconducting magnets for a future upgrade to the LHC. These new magnets will be made from niobium tin (Nb3Sn).

    “Niobium tin can go to higher fields than niobium titanium, which will give us even stronger focusing,” Wanderer said. “That will allow us to get a smaller beam, and even more collisions.” Niobium tin can also function at a slightly higher temperature, so the new magnets will be easier to cool than those currently in use.

    There are a few catches. For one, niobium tin, unlike niobium titanium, isn’t initially superconducting. The team at Brookhaven has to first heat the material for two days at 650 degrees Celsius (1200 degrees Fahrenheit) before beginning the process of turning the raw materials into the wires and cables that make up an electromagnet.

    “And when niobium tin becomes a superconductor, then it’s very brittle, which makes it really challenging,” said Wanderer. “You need tooling that can withstand the heat for two days. It needs to be very precise, to within thousandths of an inch, and when you take it out of the tooling and want to put it into a magnet, and wrap it with iron, you have to handle it very carefully. All that adds a lot to the cost. So one of the things we’ve worked out over 10 years is how to do it right the first time, almost always.”

    Fortunately, there’s still time to work out any remaining kinks. The new niobium tin magnets aren’t set to be installed at the LHC until around 2022, when the changeover from niobium titanium to niobium tin will be a crucial part of converting the Large Hadron Collider into the High-Luminosity Large Hadron Collider (HL-LHC).

    Managing Data at Higher Luminosity

    As the luminosity of the LHC increases in Run 2 and beyond, perhaps the biggest challenge facing the ATLAS team at Brookhaven lies in recognizing a potentially interesting physics event when it occurs. That selectivity is crucial, because even CERN’s worldwide computing grid—which includes about 170 global sites, and of which Brookhaven’s RHIC and ATLAS Computing Facility is a major center—can only record the tiniest fraction of over 100 million collisions that occur each second. That means it’s just as important to quickly recognize the millions of events that don’t need to be recorded as it is to recognize the handful that do.

    “What you have to do is, on the fly, analyze each event and decide whether you want to save it to disk for later use or not,” said Rajagopalan. “And you have to be careful you don’t throw away good physics events. So you’re looking for signatures. If it’s a good signature, you say, ‘Save it!’ Otherwise, you junk it. That’s how you bring the data rate down to a manageable amount you can write to disk.”

    Physicists screen out unwanted data using what’s known as a trigger system. The principle is simple: as the data from each collision comes in, it’s analyzed for a preset signature pattern, or trigger, that would mark it as potentially interesting.

    “We can change the trigger, or make the trigger more sophisticated to be more selective,” said Brookhaven’s Howard Gordon, a leader in the ATLAS physics program. “If we don’t select the right events, they are gone forever.”

    The current trigger system can handle the luminosities of Run 2, but with future upgrades it will no longer be able to screen out and reject enough collisions to keep the number of recorded events manageable. So the next generation of ATLAS triggers will have to be even more sophisticated in terms of what they can instantly detect—and reject.

    A more difficult problem comes with the few dozen events in each bunch of protons that look like they might be interesting, but aren’t.

    “Not all protons in a bunch interact, but it’s not necessarily going to be only one proton in a bunch that interacts with a proton from the opposite bunch,” said Rajagopalan. “You could have 50 of them interact. So now you have 50 events on top of each other. Imagine the software challenge when just one of those is the real, new physics we’re interested in discovering, but you have all these 49 others—junk!—sitting on top of it.”

    “We call it pileup!” Gordon quipped.

    Finding one good result among 50 is tricky enough, but in 10 years that number will be closer to 1 in 150 or 200, with all those additional extraneous results interacting with each other and adding exponentially to the complexity of the task. Being able to recognize instantly as many characteristics of the desired particles as possible will go a long way to keeping the data manageable.

    Further upgrades are planned over the next decade to cope with the ever-increasing luminosity and collision rates. For example, the Brookhaven team and collaborators will be working to develop an all-new silicon tracking system and a full replacement of the readout electronics with state-of-the-art technology that will allow physicists to collect and analyze ten times more data for LHC Run 4, scheduled for 2026.

    The physicists at CERN, Brookhaven, and elsewhere have strong motivation for meeting these challenges. Doing so will not only offer the best chance of detecting rare physics events and expanding the frontiers of physics, but would allow the physicists to do it within a reasonable timespan.

    As Rajagopalan put it, “We are ready for the challenge. The next few years are going to be an exciting time as we push forward to explore a new unchartered energy frontier.”

    Brookhaven’s role in the LHC is supported by the DOE Office of Science.

    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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  • richardmitnick 2:08 pm on May 3, 2018 Permalink | Reply
    Tags: Beam-driven atomic snapshots, BNL, Photoemission spectroscopy, , Scientists Pinpoint Energy Flowing Through Vibrations in Superconducting Crystals, SLAC UED facility, Ultra-fast electron diffraction, Vibrations through a crystalline tree   

    From Brookhaven National Laboratory: “Scientists Pinpoint Energy Flowing Through Vibrations in Superconducting Crystals” 

    Brookhaven National Laboratory

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

    Written by Justin Eure

    Interactions between electrons and the atomic structure of high-temperature superconductors impacted by elusive and powerful vibrations.

    1
    The Brookhaven/Stony Brook team (from left): Junjie Li, Yimei Zhu, Lijun Wu, Tatiana Konstantinova, and Peter Johnson.

    Manipulating the flow of energy through superconductors could radically transform technology, perhaps leading to applications such as ultra-fast, highly efficient quantum computers. But these subtle dynamics—including heat dispersion—play out with absurd speed across dizzying subatomic structures.

    Now, scientists have tracked never-before-seen interactions between electrons and the crystal lattice structure of copper-oxide superconductors. The collaboration, led by scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory, achieved measurement precision faster than one trillionth of one second through a groundbreaking combination of experimental techniques.

    “This breakthrough offers direct, fundamental insight into the puzzling characteristics of these remarkable materials,” said Brookhaven Lab scientist Yimei Zhu, who led the research. “We already had evidence of how lattice vibrations impact electron activity and disperse heat, but it was all through deduction. Now, finally, we can see it directly.”

    The results, published April 27 in the journal Science Advances, could advance research into powerful, fleeting phenomena found in copper oxides—including high-temperature superconductivity—and help scientists engineer new, better-performing materials.

    “We found a nuanced atomic landscape, where certain high-frequency, ‘hot’ vibrations within the superconductor rapidly absorb energy from electrons and increase in intensity,” said first author Tatiana Konstantinova, a PhD student at Stony Brook University doing her thesis work at Brookhaven Lab. “Other sections of the lattice, however, were slow to react. Seeing this kind of tiered interaction transforms our understanding of copper oxides.”

    Scientists used ultra-fast electron diffraction and photoemission spectroscopy to observe changes in electron energy and momentum as well as fluctuations in the atomic structure.

    Other collaborating institutions include SLAC National Accelerator Laboratory, North Carolina State University, Georgetown University, and the University of Duisburg-Essen in Germany.

    Vibrations through a crystalline tree

    The team chose Bi2Sr2CaCu2O8, a well-known superconducting copper oxide that exhibits the strong interactions central to the study. Even at temperatures close to absolute zero, the crystalline atomic lattice vibrates and very slight pulses of energy can cause the vibrations to increase in amplitude.

    “These atomic vibrations are regimented and discrete, meaning they divide across specific frequencies,” Zhu said. “We call vibrations with specific frequencies ‘phonons,’ and their interactions with flowing electrons were our target.”

    This system of interactions is a bit like the distribution of water through a tree, Konstantinova explained. Exposed to rain, only the roots can absorb the water before spreading it through the trunk and into the branches.

    “Here, the water is like energy, raining down on the branching structure of the superconductor, and the soil is like our electrons,” Konstantinova said. “But those electrons will only interact with certain phonons, which, in turn, redistribute the energy. Those phonons are like the hidden, highly interactive ‘roots’ that we needed to detect.”

    Beam-driven atomic snapshots

    The atoms flex and shift on extremely fast timescales—think 100 femtoseconds, or million billionths of a second—and those motions must be pinpointed to understand their effect. And, ideally, dissect and manipulate those interactions.

    The team used a custom-grown, layered bismuth-based compound, which can be cleaved into 100 nanometer samples through the relatively simple application of Scotch tape.

    The material was then tested using the so-called “pump-probe” technique of million-electron-volt ultrafast electron diffraction (MeV-UED). As in similar time-resolved experiments, a fast light pulse (pump) struck the sample, lasting for just 100 femtoseconds and depositing energy. An electron beam followed, bounced off the crystal lattice, and a detector measured its diffraction pattern. Repeating this process—like a series of atomic snapshots—revealed the rapid, subtle shifting of atomic vibrations over time.

    After the initial MeV-UED experiments at Brookhaven Lab, the data collection proceeded at SLAC National Accelerator Laboratory’s UED facility during the relocation of the Brookhaven instrument to another building. Colleagues at the SLAC UED facility, led by Xijie Wang, assisted on the experiment.

    The electron diffraction, however, only provided half the picture. Using time- and angle-resolved photoemission spectroscopy (tr-ARPES), the team tracked the changes in electrons within the material. An initial laser hit the sample and a second quickly followed—again with 100-femtosecond precision—to kick electrons off the surface. Detecting those flying electrons revealed changes over time in both energy and momentum.

    The tr-ARPES experiments were conducted at the facility in University Duisburg-Essen by Brookhaven Lab scientists Jonathan Rameau and Peter Johnson and their German colleagues. Scientists from North Carolina State University and Georgetown University provided theoretical support.

    “Both experimental techniques are rather sophisticated and require efforts of experts across multiple disciplines, from laser optics to accelerators and condensed matter physics,” Konstantinova said. “The caliber of the instruments and the quality of the sample allowed us to distinguish between different types of lattice vibrations.”

    The team showed that the atomic vibrations evident in the electron-lattice interactions are varied and, in some ways, counter-intuitive.

    When the lattice takes up energy from electrons, the amplitude of high-frequency phonons increases first while the lowest-frequency vibrations increase last. The different rates of energy flow between vibrations means that the sample, when subjected to a burst of photons, moves through novel stages that would be bypassed if simply exposed to heat.

    “Our data guides the new quantitative descriptions of nonequilibrium behavior in complex systems,” Konstantinova said. “The experimental approach readily applies to other exciting materials where electron-lattice interactions are of major interest.”

    This work was 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

    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 1:09 pm on April 27, 2018 Permalink | Reply
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    From Brookhaven Lab: “New High-Resolution Exascale Earth Modeling System for Energy” 

    Brookhaven Lab

    April 23, 2018

    Peter Genzer
    genzer@bnl.gov

    1
    The high-resolution E3SM earth system model simulates the strongest storms with surface winds exceeding 150 mph—hurricanes that leave cold wakes that are 2 to 4 degrees Celsius cooler than their surroundings. This simulation from E3SM represents how sea surface temperature changes evolve as a hurricane (seen here approaching the U.S. East Coast) moves across the Atlantic and how the resultant cold wake affects subsequent intensification of the next hurricane.

    2

    3
    Above 2 images-DOE’s E3SM is a state-of-the-science Earth system model development and simulation project to investigate energy-relevant science using code optimized for DOE’s advanced computers

    A new earth modeling system unveiled today will have weather-scale resolution and use advanced computers to simulate aspects of Earth’s variability and anticipate decadal changes that will critically impact the U.S. energy sector in coming years.

    After four years of development, the Energy Exascale Earth System Model (E3SM) will be released to the broader scientific community this month. The E3SM project is supported by the Department of Energy’s Office of Science in the Biological and Environmental Research Office. The E3SM release will include model code and documentation, as well as output from an initial set of benchmark simulations.

    The Earth, with its myriad interactions of atmosphere, oceans, land and ice components, presents an extraordinarily complex system for investigation. Earth system simulation involves solving approximations of physical, chemical and biological governing equations on spatial grids at resolutions that are as fine in scale as computing resources will allow.

    The E3SM project will reliably simulate aspects of earth system variability and project decadal changes that will critically impact the U.S. energy sector in the near future. These critical factors include a) regional air/water temperatures, which can strain energy grids; b) water availability, which affects power plant operations; c) extreme water-cycle events (e.g. floods and droughts), which impact infrastructure and bio-energy; and d) sea-level rise and coastal flooding which threaten coastal infrastructure.

    The goal of the project is to develop an earth system model (ESM) that has not been possible because of limitations in current computing technologies. Meeting this goal will require advances on three frontiers: 1) better resolving earth system processes through a strategic combination of developing new processes in the model, increased model resolution and enhanced computational performance; 2) representing more realistically the two-way interactions between human activities and natural processes, especially where these interactions affect U.S. energy needs; and 3) ensemble modeling to quantify uncertainty of model simulations and projections.

    “The quality and quantity of observations really makes us constrain the models,” said David Bader, Lawrence Livermore National Laboratory (LLNL) scientist and lead of the E3SM project. “With the new system, we’ll be able to more realistically simulate the present, which gives us more confidence to simulate the future.”


    The U.S. Department of Energy (DOE) today unveiled a powerful, new earth system model that uses the world’s fastest computers so that scientists can better understand how earth system processes interact today and how they may evolve in the future. The Energy Exascale Earth System model, or E3SM, is the product of four years of development by top geophysical and computational scientists across DOE’s laboratory complex. This video highlights the capabilities and goals of the E3SM project.

    [Currently, this project is running only on NERSC’s Edison system, but this project uses open source software that could ostensibly be run on any high-performance computing cluster to simulate earth systems.]

    LBL NERSC Cray XC30 Edison supercomputer

    Simulating atmospheric and oceanic fluid dynamics with fine spatial resolution is especially challenging for ESMs. The E3SM project is positioned on the forefront of this research challenge, acting on behalf of an international ESM effort. Increasing the number of earth-system days simulated per day of computing time is a prerequisite for achieving the E3SM project goal. It also is important for E3SM to effectively use the diverse computer architectures that the DOE Advanced Scientific Computing Research (ASCR) Office procures to be prepared for the uncertain future of next-generation machines. A long-term aim of the E3SM project is to use exascale machines to be procured over the next five years. The development of the E3SM is proceeding in tandem with the Exascale Computing Initiative (ECI). (An exascale refers to a computing system capable of carrying out a billion billion (109 x 109 = 1018) calculations per second. This represents a thousand-fold increase in performance over that of the most advanced computers from a decade ago),

    “This model adds a much more complete representation between interactions of the energy system and the earth system,” Bader said. “The increase in computing power allows us to add more detail to processes and interactions that results in more accurate and useful simulations than previous models.”

    To address the diverse critical factors impacting the U.S. energy sector, the E3SM project is dedicated to answering three overarching scientific questions that drive its numerical experimentation initiatives:

    Water Cycle: How does the hydrological cycle interact with the rest of the human-Earth system on local to global scales to determine water availability and water cycle extremes?
    Biogeochemistry: How do biogeochemical cycles interact with other Earth system components to influence the energy sector?
    Cryosphere Systems: How do rapid changes in cryosphere (continental and ocean ice) systems evolve with the Earth system, and contribute to sea-level rise and increased coastal vulnerability?

    In the E3SM, all model components (atmosphere, ocean, land, ice) are able to employ variable resolution to focus computing power on fine-scale processes in regions of particular interest. This is implemented using advanced mesh-designs that smoothly taper the grid-scale from the coarser outer region to the more refined region.
    The E3SM project includes more than 100 scientists and software engineers at multiple DOE Laboratories as well as several universities; the DOE laboratories include Argonne, Brookhaven, Lawrence Livermore, Lawrence Berkeley, Los Alamos, Oak Ridge, Pacific Northwest and Sandia national laboratories. In recognition of unifying the DOE earth system modeling community to perform high-resolution coupled simulations, the E3SM executive committee was awarded the Secretary of Energy’s Achievement Award in 2015.

    In addition, the E3SM project also benefits from-DOE programmatic collaborations including the Exascale Computing Project (ECP) and programs in Scientific Discovery through Advanced Computing (SciDAC), Climate Model Development and Validation (CMDV), Atmospheric Radiation Measurement (ARM), Program for Climate Model Diagnosis and Intercomparison (PCMDI), International Land Model Benchmarking Project (iLAMB), Community Earth System Model (CESM) and Next Generation Ecosystem Experiments (NGEE) for the Arctic and the Tropics.

    For information, go the E3SM website. http://e3sm.org

    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 6:44 pm on April 20, 2018 Permalink | Reply
    Tags: , , BNL, Hard X-ray Nanoprobe, , New Capabilities at NSLS-II Set to Advance Materials Science, ,   

    From BNL: “New Capabilities at NSLS-II Set to Advance Materials Science” 

    Brookhaven Lab

    The Hard X-ray Nanoprobe at Brookhaven Lab’s National Synchrotron Light Source II now offers a combination of world-leading spatial resolution and multimodal imaging.

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    Scientists at NSLS-II’s Hard X-ray Nanoprobe (HXN) spent 10 years developing advanced optics and overcoming many technical challenges in order to deliver world-leading spatial resolution and multimodal imaging at HXN.

    By channeling the intensity of x-rays, synchrotron light sources can reveal the atomic structures of countless materials. Researchers from around the world come to the National Synchrotron Light Source II (NSLS-II)—a U.S. Department of Energy (DOE) Office of Science User Facility at DOE’s Brookhaven National Laboratory—to study everything from proteins to fuel cells. NSLS-II’s ultra-bright x-rays and suite of state-of-the-art characterization tools make the facility one of the most advanced synchrotron light sources in the world. Now, NSLS-II has enhanced those capabilities even further.

    Scientists at NSLS-II’s Hard X-ray Nanoprobe (HXN) beamline, an experimental station designed to offer world-leading resolution for x-ray imaging, have demonstrated the beamline’s ability to observe materials down to 10 nanometers—about one ten-thousandth the diameter of a human hair. This exceptionally high spatial resolution will enable scientists to “see” single molecules. Moreover, HXN can now combine its high spatial resolution with multimodal scanning—the ability to simultaneously capture multiple images of different material properties. The achievement is described in the Mar. 19 issue of Nano Futures.

    “It took many years of hard work and collaboration to develop an x-ray microscopy beamline with such high spatial resolution,” said Hanfei Yan, the lead author of the paper and a scientist at HXN. “In order to realize this ambitious goal, we needed to address many technical challenges, such as reducing environmental vibrations, developing effective characterization methods, and perfecting the optics.”

    A key component for the success of this project was developing a special focusing optic called a multilayer Laue lens (MLL)—a one-dimensional artificial crystal that is engineered to bend x-rays toward a single point.

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    A close-up view of the Hard X-ray Nanoprobe—beamline 3-ID at NSLS-II.

    “Precisely developing the MLL optics to satisfy the requirements for real scientific applications took nearly 10 years,” said Nathalie Bouet, who leads the lab at NSLS-II where the MLLs were fabricated. “Now, we are proud to deliver these lenses for user science.”

    Combining multimodal and high resolution imaging is unique, and makes NSLS-II the first facility to offer this capability in the hard x-ray energy range to visiting scientists. The achievement will present a broad range of applications. In their recent paper, scientists at NSLS-II worked with the University of Connecticut and Clemson University to study a ceramic-based membrane for energy conversion application. Using the new capabilities at HXN, the group was able to image an emerging material phase that dictates the membrane’s performance.

    “We are also collaborating with researchers from industry to academia to investigate strain in nanoelectronics, local defects in self-assembled 3D superlattices, and the chemical composition variations of nanocatalysts,” Yan said. “The achievement opens up exciting opportunities in many areas of science.”

    As the new capabilities are put to use, there is an ongoing effort at HXN to continue improving the beamline’s spatial resolution and adding new capabilities.

    “Our ultimate goal is to achieve single digit resolution in 3D for imaging the elemental, chemical, and structural makeup of materials in real-time,” Yan said.

    Scientific Paper: Multimodal hard x-ray imaging with resolution approaching 10 nm for studies in material science [IOP Science – Nano Futures]

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

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    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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