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  • richardmitnick 3:13 pm on May 16, 2019 Permalink | Reply
    Tags: An open-source RNA analysis platform has been successfully used on plant cells for the first time, , , DOE Joint Genome Institute (JGI), Drop-seq, LBNL   

    From Lawrence Berkeley National Lab: “Breakthrough Technique for Studying Gene Expression Takes Root in Plants” 

    Berkeley Logo

    From Lawrence Berkeley National Lab

    May 16, 2019
    Aliyah Kovner
    akovner@lbl.gov
    510-486-6376

    Berkeley Lab scientists adapt open-source genetic analysis method for use in plant cells for the first time.

    1
    Researcher Christine Shulse tends to Arabidopsis plants in a lab at the DOE Joint Genome Institute (JGI). (Photo credit: Marilyn Chung/Berkeley Lab)

    An open-source RNA analysis platform has been successfully used on plant cells for the first time – an advance that could herald a new era of fundamental research and bolster efforts to engineer more efficient food and biofuel crop plants.

    The technology, called Drop-seq, is a popular method for measuring the RNA present in individual cells, allowing scientists to see what genes are being expressed and how this relates to the specific functions of different cell types. Developed at Harvard Medical School in 2015, the freely shared protocol had previously only been used in animal cells.

    “This is really important in understanding plant biology,” said lead researcher Diane Dickel, a scientist at the Department of Energy’s Lawrence Berkeley National Lab (Berkeley Lab). “Like humans and mice, plants have multiple cell and tissue types within them. But learning about plants on a cellular level is a little bit harder because, unlike animals, plants have cell walls, which make it hard to open the cells up for genetic study.”

    For many of the genes in plants, we have little to no understanding of what they actually do, Dickel explained. “But by knowing exactly what cell type or developmental stage a specific gene is expressed in, we can start getting a toehold into its function. In our study, we showed that Drop-seq can help us do this.”

    “We also showed that you can use these technologies to understand how plants respond to different environmental conditions at a cellular level – something many plant biologists at Berkeley Lab are interested in because being able to grow crops under poor environmental conditions, such as drought, is essential for our continued production of food and biofuel resources,” she said.

    Dickel, who studies mammalian genomics in Berkeley Lab’s Environmental Genomics and Systems Biology Division, has been using Drop-seq on animal cells for several years. An immediate fan of the platform’s ease of use and efficacy, she soon began speaking to her colleagues working on plants about trying to use it on plant cells.

    However, some were skeptical that such a project would work as easily. First off, to run plant cells through a single-cell RNA-seq analysis, they must be protoplasted – meaning they must be stripped of their cell walls using a cocktail of enzymes. This process is not easy because cells from different species and even different parts of the same plant require unique enzyme cocktails.

    2
    Microscope images of flowering plant root cells in their natural state (left) and after protoplasting (right). (Image credit: Berkshire Community College Bioscience Image Library and Department of Biological Sciences, Louisiana State University)

    Secondly, some plant biologists have expressed concern that cells are altered too significantly by protoplasting to provide insight into normal functioning. And finally, some plant cells are simply too big to be put through existing single-cell RNA-seq platforms. These technologies, which emerged in the past five years, allow scientists to assess the RNA inside thousands of cells per run; previous approaches could only analyze dozens to hundreds of cells at a time.

    Undeterred by these challenges, Dickel and her colleagues at the DOE Joint Genome Institute (JGI) teamed up with researchers from UC Davis who had perfected a protoplasting technique for root tissue from Arabidopsis thaliana (mouse-ear cress), a species of small flowering weed that serves as a plant model organism.

    After preparing samples of more than 12,000 Arabidopsis root cells, the group was thrilled when the Drop-seq process went smoother than expected. Their full results were published this week in Cell Reports.

    “When we would pitch the idea to do this in plants, people would bring up a list of reasons why it wouldn’t work,” said Dickel. “And we would say, ‘ok, but let’s just try it and see if it works’. And then it really worked. We were honestly surprised how straightforward it actually ended up being.”

    The open-source nature of the Drop-seq technology was critical for this project’s success, according to co-author Benjamin Cole, a plant genomics scientist at JGI. Because Drop-seq is inexpensive and uses easy-to-assemble components, it gave the researchers a low-risk, low-cost means to experiment. Already, a wave of interest is building. In the time leading up to their paper’s publication, Dickel and her colleagues began receiving requests – from other scientists at Berkeley Lab, JGI, and beyond – for advice on how to adapt the platform for other projects.

    “When I first spoke to Diane about trying Drop-seq in plants I recognized the huge potential, but I thought it would be difficult to separate plant cells rapidly enough to get useful data,” said John Vogel, lead scientist of plant functional genomics at JGI. “I was shocked to see how well it worked and how much they were able to learn from their initial experiment. This technique is going to be a game changer for plant biologists because it allows us to explore gene expression without grinding up whole plant organs, and the results aren’t muddled by signals from the few most common cell types.”

    3
    A cartoon diagram of the 17 different root cell types profiled using the Drop-seq protocol. (Image credit: Diane Dickel/Berkeley Lab)

    The authors anticipate that the platform, and other similar RNA-seq technologies, will eventually become routine in plant investigations. The main hurdle, Dickel noted, will be developing protoplasting methods for each project’s plant of interest.

    “Part of Berkeley Lab’s mission is to better understand how plants respond to changing environmental conditions, and how we can apply this understanding to best utilize plants for bioenergy,” noted first author Christine Shulse, who is currently a JGI affiliate. “In this work, we generated a map of gene expression in individual cell types from one plant species under two environmental conditions, which is an important first step.”

    JGI is a DOE Office of Science user facility that was originally founded to advance the landmark Human Genome Project. After helping set the stage for a new era of medical and developmental science, JGI turned its focus to investigating how plants and microbes can provide solutions to pressing energy and environmental challenges.

    This research was funded by the Laboratory Directed Research and Development (LDRD) program. The other authors were Doina Ciobanu, Junyan Lin, Yuko Yoshinaga, Mona Gouran, Gina Turco, Yiwen Zhu, Ronan O’Malley, and Siobhan Brady.

    See the full article here .

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    Bringing Science Solutions to the World

    In the world of science, Lawrence Berkeley National Laboratory (Berkeley Lab) is synonymous with “excellence.” Thirteen Nobel prizes are associated with Berkeley Lab. Seventy Lab scientists are members of the National Academy of Sciences (NAS), one of the highest honors for a scientist in the United States. Thirteen of our scientists have won the National Medal of Science, our nation’s highest award for lifetime achievement in fields of scientific research. Eighteen of our engineers have been elected to the National Academy of Engineering, and three of our scientists have been elected into the Institute of Medicine. In addition, Berkeley Lab has trained thousands of university science and engineering students who are advancing technological innovations across the nation and around the world.

    Berkeley Lab is a member of the national laboratory system supported by the U.S. Department of Energy through its Office of Science. It is managed by the University of California (UC) and is charged with conducting unclassified research across a wide range of scientific disciplines. Located on a 202-acre site in the hills above the UC Berkeley campus that offers spectacular views of the San Francisco Bay, Berkeley Lab employs approximately 3,232 scientists, engineers and support staff. The Lab’s total costs for FY 2014 were $785 million. A recent study estimates the Laboratory’s overall economic impact through direct, indirect and induced spending on the nine counties that make up the San Francisco Bay Area to be nearly $700 million annually. The Lab was also responsible for creating 5,600 jobs locally and 12,000 nationally. The overall economic impact on the national economy is estimated at $1.6 billion a year. Technologies developed at Berkeley Lab have generated billions of dollars in revenues, and thousands of jobs. Savings as a result of Berkeley Lab developments in lighting and windows, and other energy-efficient technologies, have also been in the billions of dollars.

    Berkeley Lab was founded in 1931 by Ernest Orlando Lawrence, a UC Berkeley physicist who won the 1939 Nobel Prize in physics for his invention of the cyclotron, a circular particle accelerator that opened the door to high-energy physics. It was Lawrence’s belief that scientific research is best done through teams of individuals with different fields of expertise, working together. His teamwork concept is a Berkeley Lab legacy that continues today.

    A U.S. Department of Energy National Laboratory Operated by the University of California.

    University of California Seal

    DOE Seal

     
  • richardmitnick 1:08 pm on May 13, 2019 Permalink | Reply
    Tags: "Study Concludes Glassy Menagerie of Particles in Beach Sands Near Hiroshima is Fallout Debris from A-Bomb Blast", LBNL   

    From Lawrence Berkeley National Lab: “Study Concludes Glassy Menagerie of Particles in Beach Sands Near Hiroshima is Fallout Debris from A-Bomb Blast” 

    Berkeley Logo

    From Lawrence Berkeley National Lab

    May 13, 2019

    X-ray studies at Berkeley Lab provide evidence for source of exotic assortment of melt debris.

    1
    Researchers collected and studied beach sands from locations near Hiroshima including Japan’s Miyajima Island, home to this torii gate, which at high tide is surrounded by water. The torii and associated Itsukushima Shinto Shrine, near the city of Hiroshima, are popular tourist attractions. The sand samples contained a unique collection of particles, including several that were studied at Berkeley Lab and UC Berkeley. (Credit: Ajay Suresh/Wikimedia Commons)

    Mario Wannier, a career geologist with expertise in studying tiny marine life, was methodically sorting through particles in samples of beach sand from Japan’s Motoujina Peninsula when he spotted something unexpected: a number of tiny, glassy spheres and other unusual objects.

    Wannier, who is now retired, had been comparing biological debris in beach sands from different areas in an effort to gauge the health of local and regional marine ecosystems. The work involved examining each sand particle in a sample under a microscope, and with a fine brush, separating particles of interest from grains of sediment into a tray for further study.

    A surprise in the sand grains: glassy particles

    2
    This assortment of glassy particles was discovered in beach sands near Hiroshima. (Credit: Anthropocene, Volume 25, March 2019, DOI: 10.1016/j.ancene.2019.100196)

    “I had seen hundreds of beach samples from Southeast Asia, and I can immediately distinguish mineral grains from the particles created by animals or plants, so that’s very easy,” he said. In the Motoujina sands, collected by Wannier’s colleague, Marc de Urreiztieta, he found familiar traces of single-celled organisms known as foraminifera, which come in a variety of forms. They typically have shells and reside in and around seafloor sediment.

    “But there was something else … it’s so obvious when you look at the samples,” he said. “You couldn’t miss these extraneous particles. They are generally aerodynamic, glassy, rounded – these particles immediately reminded me of some spherule (rounded) particles I had seen in sediment samples from the Cretaceous-Tertiary boundary,” the so-called K-T boundary now referred to as the Cretaceous-Paleogene (K-Pg) boundary that marked a planetary mass extinction event, including the dinosaurs’ die-off, about 66 million years ago.

    In 1980, Luis Alvarez, a Nobel Laureate who worked at Lawrence Berkeley National Laboratory (Berkeley Lab) and UC Berkeley, together with his son, geologist Walter Alvarez, proposed a theory, based on a high concentration of iridium in deposits at the K-Pg boundary, that a large meteorite impact caused this massive die-off. Coupled with more recent evidence, scientists now believe that the impact occurred in the region of the Yucatan Peninsula. In meteorite impacts, liquified ground material is ejected into the atmosphere, forming droplets of glassy material that fall back to the ground.

    Some of the glassy spheres that Wannier examined appeared to be fused together with other spheres, and others exhibited taillike features. While some of the glassy particles resembled those associated with meteorite impacts, others that Wannier found were not so familiar — among them were particles with a rubber-like composition and particles featuring a variety of materials coated in a layer or multiple layers of glass or silica. Many of the particles measured about 0.5 millimeter to 1 millimeter across.

    3
    Examples of the broad range of particles that were collected from beach sands in Japan’s Motoujima Peninsula. (Credit: Anthropocene, Volume 25, March 2019, DOI: 10.1016/j.ancene.2019.100196)

    Wannier had no idea at the time that this glassy menagerie of particles he encountered would lead to a years-long research effort that would involve scientists and experiments at Berkeley Lab and UC Berkeley. The effort would ultimately reveal the diversity and uniqueness of the studied particles, including unusual chemical and mineral mixes; the exotic high-temperature and high-pressure environment in which they formed; and the potential for new discoveries in further explorations.

    Concentration, volume of material points to A-bomb blast

    After this initial finding in 2015, Wannier traveled to Japan to collect more beach sand samples from the same region, near the city of Hiroshima.

    In all of these samples, there were between 12.6 to 23.3 grams of these spheroids and other unusual particles for every kilogram (2.2 pounds) of sand. This odd assortment of glassy particles accounted for between 0.6 percent to 2.5 percent of all of the grains that were examined. Wannier plucked about 10,000 of these particles from the sands and sorted them into six different groups according to their physical traits.

    4
    Sorted samples of particles found in beach sands in the Hiroshima area. (Credit: Mario Wannier)

    The consistently high concentrations of this strange assortment of particles in beach sands collected about 4 to 7 miles from the city of Hiroshima raised his suspicions that they may be related to the atomic bomb blast that devastated Hiroshima on the morning of Aug. 6, 1945. That bomb had instantly killed 70,000 or more people, with a final death toll accounting for the associated radiation effects possibly exceeding 145,000. The bomb and resulting firestorms mostly leveled an area measuring more than 4 square miles, and destroyed or damaged an estimated 90% of structures in the city.

    Based on the volume of the glassy debris found in the beach sands, Wannier and his colleagues estimated that a square kilometer, or roughly 0.4 square mile of beach sand in the area, collected from its surface to a depth of about 4 inches, would contain about 2,200 to 3,100 tons of the particles.

    A study detailing the analyses of the material, published in the journal Anthropocene, provides an exhaustive exploration of the many possible sources for the unusual particles, and concludes that they are A-bomb fallout from the destroyed city of Hiroshima.

    “This was the worst manmade event ever, by far,” Wannier said. “In the surprise of finding these particles, the big question for me was: You have a city, and a minute later you have no city. There was the question of: ‘Where is the city ­­– where is the material?’ It is a trove to have discovered these particles. It is an incredible story.”

    5
    This image shows sites where beach sands were collected, and the area that was devastated by the Hiroshima A-bomb blast. (Credit: Google Earth; Anthropocene, Volume 25, March 2019, DOI: 10.1016/j.ancene.2019.100196)

    Connecting with Berkeley Lab, UC Berkeley for detailed analyses

    Wannier and de Urreiztieta wanted to learn more about the samples, so they contacted Rudy Wenk, a professor of mineralogy at UC Berkeley and a longtime Berkeley Lab affiliate – Wannier and Wenk had both studied geology at the University of Basel, Switzerland, decades earlier.

    Wenk first studied the Hiroshima-area samples using an electron microscope. This enabled a detailed exploration of their composition and structures.

    He observed a wide variety in the chemical composition of the samples, including concentrations of aluminum, silicon and calcium; microscopic globules of chromium rich iron; and microscopic branching of crystalline structures. Others were composed mostly of carbon and oxygen.

    “Some of these look similar to what we have from meteorite impacts, but the composition is quite different,” Wenk said. “There were quite unusual shapes. There was some pure iron and steel. Some of these had the composition of building materials.”

    To gather further details about the samples, Wenk turned to Berkeley Lab, where he and his students have conducted many electron microscopy and X-ray experiments over the years. He took selected samples to Berkeley Lab’s Advanced Light Source (ALS) and conducted a number of measurements there.

    Nobumichi “Nobu” Tamura, a staff scientist at the ALS who Wenk had worked with before, along with then-ALS colleagues Camelia Stan and Binbin Yue (Stan and Yue have since left Berkeley Lab), assisted in analyzing the samples at a scale of less than 1 micron, or 1 millionth of a meter, using a technique known as X-ray microdiffraction.

    Both of Tamura’s parents were born in Japan, and he said that he was personally interested in participating in the study because of his family ancestry. “My dad was 12 years old when the bombing happened, and lived just 200 miles north of Hiroshima, so he witnessed directly the news and outcomes of these terrible events,” Tamura said.

    The experiments and related analyses determined that the particles had formed in extreme conditions, with temperatures exceeding 3,300 degrees Fahrenheit (1,800 Celsius), as evidenced by the assemblage of anorthite and mullite crystals that the researchers identified.

    Tamura noted that the unique microstructure of the studied particles and the sheer volume of melt debris present also provide strong evidence for how they were formed.

    “The atomic explosion hypothesis is the only logical explanation for their origin,” he said.

    Study details researchers’ findings

    Many of the sphere-shaped particles and other bits likely formed at a high elevation around the rising fireball of the blast. The materials swept up from the ground bubbled and mixed in this turbulent environment before cooling and condensing and then raining down.

    Wannier explained the processes that likely formed the materials in an atomic cloud: “The ground material is volatized and moved into the cloud, where the high temperature changes the physical condition,” Wannier said. “There are a lot of interactions between particles. There are lots of little spheres that collide, and you get this agglomeration.”

    Researchers also found that the composition of the debris particles corresponds closely with materials that were common in Hiroshima at the time of the bombing, such as concrete, marble, stainless steel, and rubber.

    Other studies have analyzed melt debris from the Trinity test site in New Mexico – where the first nuclear explosion was triggered – and from underground nuclear test sites in Nevada. But those samples have a distinctly different composition that is associated with their local geological environment.

    The Trinity debris is dubbed trinitite, and researchers in the latest study have dubbed the melt particles they studied as Hiroshimaite to highlight their distinct characteristics and their likely origin in the Hiroshima A-bomb explosion.

    “Hiroshimaite particles are much more complex and diverse than trinitites,” Tamura said, owing to their likely genesis in Hiroshima’s urban center.

    While there had been concerted international efforts to aid survivors suffering from radiation effects, to measure the radiation levels, and to assess the overall damage caused by the 1945 atomic bombings in Hiroshima and Nagasaki, the study noted that the melt debris associated with these bombings had apparently not been previously studied.

    The latest study encourages additional tests to find out if any samples carry radioactive elements, and to conduct further studies in the Hiroshima and Nagasaki areas.

    Plans for follow-up studies

    Wannier said he has received soil samples from ground zero at Hiroshima and may look for debris samples from deeper underground there, and he has also received a soil sample containing glassy debris from a streambed about 19 miles northwest of where the Hiroshima A-bomb struck – historic records show that area was in the path of the atomic cloud.

    He said he also hopes to explore whether the melt debris exhibits similarities to materials associated with volcanic eruptions.

    Tamura and Wenk noted that this initial study focused on just a small number of melt debris particles, and it may be worthwhile to pursue a larger study to learn more about the extreme conditions that produced the debris and to possibly reveal more unique chemistry or mineralogy.

    Wenk added, “It was quite fascinating to look at all of these materials. What we hope is to get other people interested in looking at this in more detail, and in looking for examples around the Nagasaki A-bomb site.”

    Wenk sent a copy of the latest study to Jun-Ichi Ando, a professor in the Department of Earth and Planetary Systems Science in the Graduate School of Science at Hiroshima University – they had met while Wenk was serving as a visiting professor at Hiroshima University in 1998.

    “I think this kind of research is very important for Hiroshima University, as a university located at the A-bomb site,” Ando said, noting that he shared the study with a colleague who is a mineralogist and studies the Yucatan-region’s meteorite impact. He also shared it with Rebun Kayo, a research fellow at the university who leads an outreach group that raises awareness about nuclear weapons by sharing bomb-scarred Hiroshima roof tiles and bricks with institutions around the world.

    In an unrelated effort, Ando has studied a large chunk of granite associated with the Atomic Bomb Dome structure in Hiroshima – it was the only building that remained standing near ground zero. Kayo found and recovered the piece of granite from a local riverbed near the domed building in 2017. It is also known as the Genbaku Dome or Hiroshima Peace Memorial.

    “I tried to find evidence of melting and the shock wave recorded on the surface of the granite pillar” using electron microscopy, Ando said – his own research typically focuses on microstructures of rocks in seismic faults.

    Wannier said the debris study has been an enlightening journey for him, and he hopes to continue with the research. “For 70-plus years this material has been there and was never studied in detail. We hope this raises attention among the scientific community,” he said.

    “We hope people take advantage of this opportunity.”

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Bringing Science Solutions to the World

    In the world of science, Lawrence Berkeley National Laboratory (Berkeley Lab) is synonymous with “excellence.” Thirteen Nobel prizes are associated with Berkeley Lab. Seventy Lab scientists are members of the National Academy of Sciences (NAS), one of the highest honors for a scientist in the United States. Thirteen of our scientists have won the National Medal of Science, our nation’s highest award for lifetime achievement in fields of scientific research. Eighteen of our engineers have been elected to the National Academy of Engineering, and three of our scientists have been elected into the Institute of Medicine. In addition, Berkeley Lab has trained thousands of university science and engineering students who are advancing technological innovations across the nation and around the world.

    Berkeley Lab is a member of the national laboratory system supported by the U.S. Department of Energy through its Office of Science. It is managed by the University of California (UC) and is charged with conducting unclassified research across a wide range of scientific disciplines. Located on a 202-acre site in the hills above the UC Berkeley campus that offers spectacular views of the San Francisco Bay, Berkeley Lab employs approximately 3,232 scientists, engineers and support staff. The Lab’s total costs for FY 2014 were $785 million. A recent study estimates the Laboratory’s overall economic impact through direct, indirect and induced spending on the nine counties that make up the San Francisco Bay Area to be nearly $700 million annually. The Lab was also responsible for creating 5,600 jobs locally and 12,000 nationally. The overall economic impact on the national economy is estimated at $1.6 billion a year. Technologies developed at Berkeley Lab have generated billions of dollars in revenues, and thousands of jobs. Savings as a result of Berkeley Lab developments in lighting and windows, and other energy-efficient technologies, have also been in the billions of dollars.

    Berkeley Lab was founded in 1931 by Ernest Orlando Lawrence, a UC Berkeley physicist who won the 1939 Nobel Prize in physics for his invention of the cyclotron, a circular particle accelerator that opened the door to high-energy physics. It was Lawrence’s belief that scientific research is best done through teams of individuals with different fields of expertise, working together. His teamwork concept is a Berkeley Lab legacy that continues today.

    A U.S. Department of Energy National Laboratory Operated by the University of California.

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    • Skyscapes for the Soul 9:30 am on May 14, 2019 Permalink | Reply

      Very, very interesting. I am wondering thus if the similarity between these ‘Hiroshima’ particles and the ones at the K-T boundary can add to the theory that we were hit by a meteorite at that time.

      Like

      • richardmitnick 11:07 am on May 14, 2019 Permalink | Reply

        Thanks for the question. A you know, I am not a scientist, so I am not qualified to answer your question. LBNL did not provide writer(s) for this article, only media@lbl.gov 510-486-5183. You can try to find your way to someone knowledgeable on this subject by emailing the offered contact and ask for direction to the right people.

        Thanks again.

        Like

  • richardmitnick 8:43 am on May 9, 2019 Permalink | Reply
    Tags: "A New Filter to Better Map the Dark Universe", , , “Lensing can magnify or demagnify things. It also distorts them along a certain axis so they are stretched in one direction.”, , , , , LBNL, The researchers found that a certain lensing signature called shearing seems largely immune to the foreground “noise” effects that otherwise interfere with the CMB lensing data.,   

    From Lawrence Berkeley National Lab: “A New Filter to Better Map the Dark Universe” 

    Berkeley Logo

    From Lawrence Berkeley National Lab

    May 8, 2019
    Glenn Roberts Jr.
    geroberts@lbl.gov
    (510) 486-5582

    1
    Just as a wine glass distorts an image, showing temperature fluctuations in the cosmic microwave background [CMB] in this photo illustration, large objects like galaxy clusters and galaxies can similarly distort this light to produce lensing effects. (Credit: Emmanuel Schaan and Simone Ferraro/Berkeley Lab)

    The earliest known light in our universe, known as the cosmic microwave background [CMB], was emitted about 380,000 years after the Big Bang.

    CMB per ESA/Planck


    ESA/Planck 2009 to 2013

    The patterning of this relic light holds many important clues to the development and distribution of large-scale structures such as galaxies and galaxy clusters.

    Gravitational Lensing NASA/ESA

    Distortions in the cosmic microwave background (CMB), caused by a phenomenon known as lensing, can further illuminate the structure of the universe and can even tell us things about the mysterious, unseen universe – including dark energy, which makes up about 68 percent of the universe and accounts for its accelerating expansion, and dark matter, which accounts for about 27 percent of the universe.

    Set a stemmed wine glass on a surface, and you can see how lensing effects can simultaneously magnify, squeeze, and stretch the view of the surface beneath it. In lensing of the CMB, gravity effects from large objects like galaxies and galaxy clusters bend the CMB light in different ways. These lensing effects can be subtle (known as weak lensing) for distant and small galaxies, and computer programs can identify them because they disrupt the regular CMB patterning.

    Weak gravitational lensing NASA/ESA Hubble

    There are some known issues with the accuracy of lensing measurements, though, and particularly with temperature-based measurements of the CMB and associated lensing effects.

    While lensing can be a powerful tool for studying the invisible universe, and could even potentially help us sort out the properties of ghostly subatomic particles like neutrinos, the universe is an inherently messy place.

    And like bugs on a car’s windshield during a long drive, the gas and dust swirling in other galaxies, among other factors, can obscure our view and lead to faulty readings of the CMB lensing.

    There are some filtering tools that help researchers to limit or mask some of these effects, but these known obstructions continue to be a major problem in the many studies that rely on temperature-based measurements.

    The effects of this interference with temperature-based CMB studies can lead to erroneous lensing measurements, said Emmanuel Schaan, a postdoctoral researcher and Owen Chamberlain Postdoctoral Fellow in the Physics Division at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab).

    “You can be wrong and not know it,” Schaan said. “The existing methods don’t work perfectly – they are really limiting.”

    To address this problem, Schaan teamed up with Simone Ferraro, a Divisional Fellow in Berkeley Lab’s Physics Division, to develop a way to improve the clarity and accuracy of CMB lensing measurements by separately accounting for different types of lensing effects.

    “Lensing can magnify or demagnify things. It also distorts them along a certain axis so they are stretched in one direction,” Schaan said.

    The researchers found that a certain lensing signature called shearing, which causes this stretching in one direction, seems largely immune to the foreground “noise” effects that otherwise interfere with the CMB lensing data. The lensing effect known as magnification, meanwhile, is prone to errors introduced by foreground noise. Their study, published May 8 in the journal Physical Review Letters, notes a “dramatic reduction” in this error margin when focusing solely on shearing effects.

    3
    A set of cosmic microwave background images with no lensing effects (top row) and with exaggerated cosmic microwave background lensing effects (bottom row). (Credit: Wayne Hu and Takemi Okamoto/University of Chicago)

    The sources of the lensing, which are large objects that stand between us and the CMB light, are typically galaxy groups and clusters that have a roughly spherical profile in temperature maps, Ferraro noted, and the latest study found that the emission of various forms of light from these “foreground” objects only appears to mimic the magnification effects in lensing but not the shear effects.

    “So we said, ‘Let’s rely only on the shear and we’ll be immune to foreground effects,’” Ferraro said. “When you have many of these galaxies that are mostly spherical, and you average them, they only contaminate the magnification part of the measurement. For shear, all of the errors are basically gone.”

    He added, “It reduces the noise, allowing us to get better maps. And we’re more certain that these maps are correct,” even when the measurements involve very distant galaxies as foreground lensing objects.

    The new method could benefit a range of sky-surveying experiments, the study notes, including the POLARBEAR-2 and Simons Array experiments, which have Berkeley Lab and UC Berkeley participants; the Advanced Atacama Cosmology Telescope (AdvACT) project; and the South Pole Telescope – 3G camera (SPT-3G). It could also aid the Simons Observatory and the proposed next-generation, multilocation CMB experiment known as CMB-S4 – Berkeley Lab scientists are involved in the planning for both of these efforts.

    POLARBEAR McGill Telescope located in the Atacama Desert of northern Chile in the Antofagasta Region. The POLARBEAR experiment is mounted on the Huan Tran Telescope (HTT) at the James Ax Observatory in the Chajnantor Science Reserve.

    LBL The Simons Array in the Atacama in Chile, with the 6 meter Atacama Cosmology Telescope

    South Pole Telescope SPTPOL. The SPT collaboration is made up of over a dozen (mostly North American) institutions, including the University of Chicago, the University of California, Berkeley, Case Western Reserve University, Harvard/Smithsonian Astrophysical Observatory, the University of Colorado Boulder, McGill University, The University of Illinois at Urbana-Champaign, University of California, Davis, Ludwig Maximilian University of Munich, Argonne National Laboratory, and the National Institute for Standards and Technology. It is funded by the National Science Foundation.

    South Pole Telescope SPT-3G Camera

    The method could also enhance the science yield from future galaxy surveys like the Berkeley Lab-led Dark Energy Spectroscopic Instrument (DESI) project under construction near Tucson, Arizona, and the Large Synoptic Survey Telescope (LSST) project under construction in Chile, through joint analyses of data from these sky surveys and the CMB lensing data.

    LBNL/DESI spectroscopic instrument on the Mayall 4-meter telescope at Kitt Peak National Observatory starting in 2018


    NOAO/Mayall 4 m telescope at Kitt Peak, Arizona, USA, Altitude 2,120 m (6,960 ft)


    Kitt Peak National Observatory of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono O’odham Nation, 88 kilometers 55 mi west-southwest of Tucson, Arizona, Altitude 2,096 m (6,877 ft)

    LSST


    LSST Camera, built at SLAC



    LSST telescope, currently under construction on the El Peñón peak at Cerro Pachón Chile, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile, alongside the existing Gemini South and Southern Astrophysical Research Telescopes.


    LSST Data Journey, Illustration by Sandbox Studio, Chicago with Ana Kova

    Increasingly large datasets from astrophysics experiments have led to more coordination in comparing data across experiments to provide more meaningful results. “These days, the synergies between CMB and galaxy surveys are a big deal,” Ferraro said.

    4
    These images show different types of emissions that can interfere with CMB lensing measurements, as simulated by Neelima Sehgal and collaborators. From left to right: The cosmic infrared background, composed of intergalactic dust; radio point sources, or radio emission from other galaxies; the kinematic Sunyaev-Zel’dovich effect, a product of gas in other galaxies; and the thermal Sunyaev-Zel’dovich effect, which also relates to gas in other galaxies. (Credit: Emmanuel Schaan and Simone Ferraro/Berkeley Lab)

    In this study, researchers relied on simulated full-sky CMB data. They used resources at Berkeley Lab’s National Energy Research Scientific Computing Center (NERSC) to test their method on each of the four different foreground sources of noise, which include infrared, radiofrequency, thermal, and electron-interaction effects that can contaminate CMB lensing measurements.

    NERSC

    NERSC Cray Cori II supercomputer at NERSC at LBNL, named after Gerty Cori, the first American woman to win a Nobel Prize in science

    NERSC Hopper Cray XE6 supercomputer


    LBL NERSC Cray XC30 Edison supercomputer


    The Genepool system is a cluster dedicated to the DOE Joint Genome Institute’s computing needs. Denovo is a smaller test system for Genepool that is primarily used by NERSC staff to test new system configurations and software.

    NERSC PDSF


    PDSF is a networked distributed computing cluster designed primarily to meet the detector simulation and data analysis requirements of physics, astrophysics and nuclear science collaborations.

    Future:

    Cray Shasta Perlmutter SC18 AMD Epyc Nvidia pre-exascale supeercomputer

    The study notes that cosmic infrared background noise, and noise from the interaction of CMB light particles (photons) with high-energy electrons have been the most problematic sources to address using standard filtering tools in CMB measurements. Some existing and future CMB experiments seek to lessen these effects by taking precise measurements of the polarization, or orientation, of the CMB light signature rather than its temperature.

    “We couldn’t have done this project without a computing cluster like NERSC,” Schaan said. NERSC has also proved useful in serving up other universe simulations to help prepare for upcoming experiments like DESI (see related article).

    The method developed by Schaan and Ferraro is already being implemented in the analysis of current experiments’ data. One possible application is to develop more detailed visualizations of dark matter filaments and nodes that appear to connect matter in the universe via a complex and changing cosmic web.

    The researchers reported a positive reception to their newly introduced method.

    “This was an outstanding problem that many people had thought about,” Ferraro said. “We’re happy to find elegant solutions.”

    NERSC is a DOE Office of Science User Facility.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Bringing Science Solutions to the World

    In the world of science, Lawrence Berkeley National Laboratory (Berkeley Lab) is synonymous with “excellence.” Thirteen Nobel prizes are associated with Berkeley Lab. Seventy Lab scientists are members of the National Academy of Sciences (NAS), one of the highest honors for a scientist in the United States. Thirteen of our scientists have won the National Medal of Science, our nation’s highest award for lifetime achievement in fields of scientific research. Eighteen of our engineers have been elected to the National Academy of Engineering, and three of our scientists have been elected into the Institute of Medicine. In addition, Berkeley Lab has trained thousands of university science and engineering students who are advancing technological innovations across the nation and around the world.

    Berkeley Lab is a member of the national laboratory system supported by the U.S. Department of Energy through its Office of Science. It is managed by the University of California (UC) and is charged with conducting unclassified research across a wide range of scientific disciplines. Located on a 202-acre site in the hills above the UC Berkeley campus that offers spectacular views of the San Francisco Bay, Berkeley Lab employs approximately 3,232 scientists, engineers and support staff. The Lab’s total costs for FY 2014 were $785 million. A recent study estimates the Laboratory’s overall economic impact through direct, indirect and induced spending on the nine counties that make up the San Francisco Bay Area to be nearly $700 million annually. The Lab was also responsible for creating 5,600 jobs locally and 12,000 nationally. The overall economic impact on the national economy is estimated at $1.6 billion a year. Technologies developed at Berkeley Lab have generated billions of dollars in revenues, and thousands of jobs. Savings as a result of Berkeley Lab developments in lighting and windows, and other energy-efficient technologies, have also been in the billions of dollars.

    Berkeley Lab was founded in 1931 by Ernest Orlando Lawrence, a UC Berkeley physicist who won the 1939 Nobel Prize in physics for his invention of the cyclotron, a circular particle accelerator that opened the door to high-energy physics. It was Lawrence’s belief that scientific research is best done through teams of individuals with different fields of expertise, working together. His teamwork concept is a Berkeley Lab legacy that continues today.

    A U.S. Department of Energy National Laboratory Operated by the University of California.

    University of California Seal

    DOE Seal

     
  • richardmitnick 12:52 pm on May 6, 2019 Permalink | Reply
    Tags: , , LBNL, Moving toward a circular plastic future, PDK-a recyclable plastic that like a Lego playset can be disassembled into its constituent parts at the molecular level and then reassembled into a different shape; texture; and color again and again , PDK-poly(diketoenamine) plastic, Recycling plastic one monomer at a time   

    From Lawrence Berkeley National Lab- “Plastic Gets a Do-Over: Breakthrough Discovery Recycles Plastic From the Inside Out” 

    Berkeley Logo

    From Lawrence Berkeley National Lab

    May 6, 2019
    Theresa Duque

    Scientists from Berkeley Lab have made a next-generation plastic that can be recycled again and again into new materials of any color, shape, or form.

    1
    Credit: iStock/Mukhina1

    Light yet sturdy, plastic is great – until you no longer need it. Because plastics contain various additives, like dyes, fillers, or flame retardants, very few plastics can be recycled without loss in performance or aesthetics. Even the most recyclable plastic, PET – or poly(ethylene terephthalate) – is only recycled at a rate of 20-30%, with the rest typically going to incinerators or landfills, where the carbon-rich material takes centuries to decompose.

    Now a team of researchers at the U.S. Department of Energy’s (DOE) Lawrence Berkeley National Laboratory (Berkeley Lab) has designed a recyclable plastic that, like a Lego playset, can be disassembled into its constituent parts at the molecular level, and then reassembled into a different shape, texture, and color again and again without loss of performance or quality. The new material, called poly(diketoenamine), or PDK, was reported in the journal Nature Chemistry.

    2
    Left to right: Peter Christensen, Kathryn Loeffler, and Brett Helms. (Credit: Marilyn Chung/Berkeley Lab)

    “Most plastics were never made to be recycled,” said lead author Peter Christensen, a postdoctoral researcher at Berkeley Lab’s Molecular Foundry. “But we have discovered a new way to assemble plastics that takes recycling into consideration from a molecular perspective.”

    LBNL Molecular Foundry

    Christensen was part of a multidisciplinary team led by Brett Helms, a staff scientist in Berkeley Lab’s Molecular Foundry. The other co-authors are undergraduate researchers Angelique Scheuermann (then of UC Berkeley) and Kathryn Loeffler (then of the University of Texas at Austin) who were funded by DOE’s Science Undergraduate Laboratory Internship (SULI) program at the time of the study.

    All plastics, from water bottles to automobile parts, are made up of large molecules called polymers, which are composed of repeating units of shorter carbon-containing compounds called monomers.

    According to the researchers, the problem with many plastics is that the chemicals added to make them useful – such as fillers that make a plastic tough, or plasticizers that make a plastic flexible – are tightly bound to the monomers and stay in the plastic even after it’s been processed at a recycling plant.

    During processing at such plants, plastics with different chemical compositions – hard plastics, stretchy plastics, clear plastics, candy-colored plastics – are mixed together and ground into bits. When that hodgepodge of chopped-up plastics is melted to make a new material, it’s hard to predict which properties it will inherit from the original plastics.

    3
    Unlike conventional plastics, the monomers of PDK plastic could be recovered and freed from any compounded additives simply by dunking the material in a highly acidic solution. (Credit: Peter Christensen et al./Berkeley Lab)

    This inheritance of unknown and therefore unpredictable properties has prevented plastic from becoming what many consider the Holy Grail of recycling: a “circular” material whose original monomers can be recovered for reuse for as long as possible, or “upcycled” to make a new, higher quality product.

    So, when a reusable shopping bag made with recycled plastic gets threadbare with wear and tear, it can’t be upcycled or even recycled to make a new product. And once the bag has reached its end of life, it’s either incinerated to make heat, electricity, or fuel, or ends up in a landfill, Helms said.

    “Circular plastics and plastics upcycling are grand challenges,” he said. “We’ve already seen the impact of plastic waste leaking into our aquatic ecosystems, and this trend is likely to be exacerbated by the increasing amounts of plastics being manufactured and the downstream pressure it places on our municipal recycling infrastructure.”

    Recycling plastic one monomer at a time

    4
    This time-lapse video shows a piece of PDK plastic in acid as it degrades to its molecular building blocks – monomers. The acid helps to break the bonds between the monomers and separate them from the chemical additives that give plastic its look and feel. (Credit: Peter Christensen/ Berkeley Lab)

    The researchers want to divert plastics from landfills and the oceans by incentivizing the recovery and reuse of plastics, which could be possible with polymers formed from PDKs. “With PDKs, the immutable bonds of conventional plastics are replaced with reversible bonds that allow the plastic to be recycled more effectively,” Helms said.

    Unlike conventional plastics, the monomers of PDK plastic could be recovered and freed from any compounded additives simply by dunking the material in a highly acidic solution. The acid helps to break the bonds between the monomers and separate them from the chemical additives that give plastic its look and feel.

    “We’re interested in the chemistry that redirects plastic lifecycles from linear to circular,” said Helms. “We see an opportunity to make a difference for where there are no recycling options.” That includes adhesives, phone cases, watch bands, shoes, computer cables, and hard thermosets that are created by molding hot plastic material.

    The researchers first discovered the exciting circular property of PDK-based plastics when Christensen was applying various acids to glassware used to make PDK adhesives, and noticed that the adhesive’s composition had changed. Curious as to how the adhesive might have been transformed, Christensen analyzed the sample’s molecular structure with an NMR (nuclear magnetic resonance) spectroscopy instrument. “To our surprise, they were the original monomers,” Helms said.

    After testing various formulations at the Molecular Foundry, they demonstrated that not only does acid break down PDK polymers into monomers, but the process also allows the monomers to be separated from entwined additives.

    Next, they proved that the recovered PDK monomers can be remade into polymers, and those recycled polymers can form new plastic materials without inheriting the color or other features of the original material – so that broken black watchband you tossed in the trash could find new life as a computer keyboard if it’s made with PDK plastic. They could also upcycle the plastic by adding additional features, such as flexibility.

    Moving toward a circular plastic future

    5
    PDK plastics are a “circular” material whose original monomers can be recovered for reuse for as long as possible, or “upcycled” to make a new, higher quality product. (Credit: Peter Christensen et al./Berkeley Lab)

    The researchers believe that their new recyclable plastic could be a good alternative to many nonrecyclable plastics in use today.

    “We’re at a critical point where we need to think about the infrastructure needed to modernize recycling facilities for future waste sorting and processing,” said Helms. “If these facilities were designed to recycle or upcycle PDK and related plastics, then we would be able to more effectively divert plastic from landfills and the oceans. This is an exciting time to start thinking about how to design both materials and recycling facilities to enable circular plastics,” said Helms.

    The researchers next plan to develop PDK plastics with a wide range of thermal and mechanical properties for applications as diverse as textiles, 3D printing, and foams. In addition, they are looking to expand the formulations by incorporating plant-based materials and other sustainable sources.

    The Molecular Foundry is a DOE Office of Science User Facility that specializes in nanoscale science.

    This work was supported by the DOE’s Laboratory Directed Research and Development (LDRD) program with additional funding provided by the DOE Office of Science through the SULI program.

    The technology is available for licensing and collaboration. If interested, please contact Berkeley Lab’s Intellectual Property Office, ipo@lbl.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

    Bringing Science Solutions to the World

    In the world of science, Lawrence Berkeley National Laboratory (Berkeley Lab) is synonymous with “excellence.” Thirteen Nobel prizes are associated with Berkeley Lab. Seventy Lab scientists are members of the National Academy of Sciences (NAS), one of the highest honors for a scientist in the United States. Thirteen of our scientists have won the National Medal of Science, our nation’s highest award for lifetime achievement in fields of scientific research. Eighteen of our engineers have been elected to the National Academy of Engineering, and three of our scientists have been elected into the Institute of Medicine. In addition, Berkeley Lab has trained thousands of university science and engineering students who are advancing technological innovations across the nation and around the world.

    Berkeley Lab is a member of the national laboratory system supported by the U.S. Department of Energy through its Office of Science. It is managed by the University of California (UC) and is charged with conducting unclassified research across a wide range of scientific disciplines. Located on a 202-acre site in the hills above the UC Berkeley campus that offers spectacular views of the San Francisco Bay, Berkeley Lab employs approximately 3,232 scientists, engineers and support staff. The Lab’s total costs for FY 2014 were $785 million. A recent study estimates the Laboratory’s overall economic impact through direct, indirect and induced spending on the nine counties that make up the San Francisco Bay Area to be nearly $700 million annually. The Lab was also responsible for creating 5,600 jobs locally and 12,000 nationally. The overall economic impact on the national economy is estimated at $1.6 billion a year. Technologies developed at Berkeley Lab have generated billions of dollars in revenues, and thousands of jobs. Savings as a result of Berkeley Lab developments in lighting and windows, and other energy-efficient technologies, have also been in the billions of dollars.

    Berkeley Lab was founded in 1931 by Ernest Orlando Lawrence, a UC Berkeley physicist who won the 1939 Nobel Prize in physics for his invention of the cyclotron, a circular particle accelerator that opened the door to high-energy physics. It was Lawrence’s belief that scientific research is best done through teams of individuals with different fields of expertise, working together. His teamwork concept is a Berkeley Lab legacy that continues today.

    A U.S. Department of Energy National Laboratory Operated by the University of California.

    University of California Seal

    DOE Seal

     
  • richardmitnick 11:43 am on May 1, 2019 Permalink | Reply
    Tags: "The ‘Little’ Computer Cluster That Could" The Parallel Distributed Systems Facility (PDSF) cluster, , , LBNL, ,   

    From Lawrence Berkeley National Lab: “The ‘Little’ Computer Cluster That Could” 

    Berkeley Logo

    From Lawrence Berkeley National Lab

    May 1, 2019
    Glenn Roberts Jr.
    geroberts@lbl.gov
    (510) 486-5582

    Decades before “big data” and “the cloud” were a part of our everyday lives and conversations, a custom computer cluster based at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) enabled physicists around the world to remotely and simultaneously analyze and visualize data.

    2
    The PDSF computer cluster in 2003. (Credit: Berkeley lab)

    The Parallel Distributed Systems Facility (PDSF) cluster, which had served as a steady workhorse in supporting groundbreaking and even Nobel-winning research around the world since the 1990s, switched off last month.

    NERSC PDSF

    During its lifetime the cluster and its dedicated support team racked up many computing achievements and innovations in support of large collaborative efforts in nuclear physics and high-energy physics. Some of these innovations have persevered and evolved in other systems.

    The cluster handled data for experiments that produce a primordial “soup” of subatomic particles to teach us about the makings of matter, search for intergalactic particle signals deep within Antarctic ice, and hunt for dark matter in a mile-deep tank of liquid xenon at a former mine site. It also handled data for a space observatory mapping the universe’s earliest light, and for Earth-based observations of supernovas.

    It supported research leading to the discoveries of the morphing abilities of ghostly particles called neutrinos, the existence of the Higgs boson and the related Higgs field that generates mass through particle interactions, and the accelerating expansion rate of the universe that is attributed to a mysterious force called dark energy.

    CERN CMS Higgs Event


    CERN ATLAS Higgs Event

    Lambda-Cold Dark Matter, Accelerated Expansion of the Universe, Big Bang-Inflation (timeline of the universe) Date 2010 Credit: Alex Mittelmann Cold creation

    Dark Energy Camera Enables Astronomers a Glimpse at the Cosmic Dawn. CREDIT National Astronomical Observatory of Japan

    Some of PDSF’s collaboration users have transitioned to the Cori supercomputer at Berkeley Lab’s National Energy Research Scientific Computing Center (NERSC), with other participants moving to other systems. The transition to Cori gives users access to more computing power in an era of increasingly hefty and complex datasets and demands.

    NERSC

    NERSC Cray Cori II supercomputer at NERSC at LBNL, named after Gerty Cori, the first American woman to win a Nobel Prize in science

    NERSC Hopper Cray XE6 supercomputer


    LBL NERSC Cray XC30 Edison supercomputer


    The Genepool system is a cluster dedicated to the DOE Joint Genome Institute’s computing needs. Denovo is a smaller test system for Genepool that is primarily used by NERSC staff to test new system configurations and software.

    NERSC PDSF


    PDSF is a networked distributed computing cluster designed primarily to meet the detector simulation and data analysis requirements of physics, astrophysics and nuclear science collaborations.

    Future:

    Cray Shasta Perlmutter SC18 AMD Epyc Nvidia pre-exascale supeercomputer

    “A lot of great physics and science was done at PDSF,” said Richard Shane Canon, a project engineer at NERSC who served as a system lead for PDSF from 2003-05. “We learned a lot of cool things from it, and some of those things even became part of how we run our supercomputers today. It was also a unique partnership between experiments and a supercomputing facility – it was the first of its kind.”

    PDSF was small when compared to its supercomputer counterparts that handle a heavier load of computer processors, data, and users, but it had developed a reputation for being responsive and adaptable, and its support crew over the years often included physicists who understood the science as well as the hardware and software capabilities and limitations.

    “It was ‘The Little Engine That Could,’” said Iwona Sakrejda, a nuclear physicist who supported PDSF and its users for over a decade in a variety of roles at NERSC and retired from Berkeley Lab in 2015. “It was the ‘boutique’ computer cluster.”

    PDSF, because it was small and flexible, offered an R&D environment that allowed researchers to test out new ideas for analyzing and visualizing data. Such an environment may have been harder to find on larger systems, she said. Its size also afforded a personal touch.

    “When things didn’t work, they had more handholding,” she added, recalling the numerous researchers that she guided through the PDSF system – including early career researchers working on their theses.

    “It was gratifying. I developed a really good relationship with the users,” Sakrejda said. “I understood what they were trying to do and how their programs worked, which was important in creating the right architecture for what they were trying to accomplish.”

    She noted that because the PDSF system was constantly refreshed, it sometimes led to an odd assortment of equipment put together from different generations of hardware, in sharp contrast to the largely homogenous architecture of today’s supercomputers.

    PDSF participants included collaborations for the Sudbury Neutrino Observatory (SNO) in Canada, the Solenoid Tracker at Brookhaven National Laboratory’s Relativistic Heavy Ion Collider (STAR), IceCube near the South Pole, Daya Bay in China, the Cryogenic Underground Observatory for Rare Events (CUORE) in Italy, the Large Underground Xenon (LUX), LUX-ZEPLIN (LZ), and MAJORANA experiments in South Dakota, the Collider Detector at Fermilab (CDF), and the ATLAS Experiment and A Large Ion Collider Experiment (ALICE) at Europe’s CERN laboratory, among others. The most data-intensive experiments use a distributed system of clusters like PDSF.

    SNOLAB, a Canadian underground physics laboratory at a depth of 2 km in Vale’s Creighton nickel mine in Sudbury, Ontario

    BNL/RHIC Star Detector

    U Wisconsin ICECUBE neutrino detector at the South Pole

    Daya Bay, approximately 52 kilometers northeast of Hong Kong and 45 kilometers east of Shenzhen, China

    CUORE experiment,at the Italian National Institute for Nuclear Physics’ (INFN’s) Gran Sasso National Laboratories (LNGS) in Italy,a search for neutrinoless double beta decay

    LBNL LZ project at SURF, Lead, SD, USA

    U Washington Majorana Demonstrator Experiment at SURF

    FNAL/Tevatron CDF detector

    CERN ATLAS Image Claudia Marcelloni ATLAS CERN

    CERN/ALICE Detector

    3
    This chart shows the physics collaborations that used PDSF over the years, with the heaviest usage by the STAR and ALICE collaborations. (Credit: Berkeley Lab)

    The STAR collaboration was the original participant and had by far the highest overall use of PDSF, and the ALICE collaboration had grown to become one of the largest PDSF users by 2010. Both experiments have explored the formation and properties of an exotic superhot particle soup known as the quark-gluon plasma by colliding heavy particles.

    SNO researchers’ findings about neutrinos’ mass and ability to change into different forms or flavors led to the 2015 Nobel Prize in physics. And PDSF played a notable role in the early analyses of SNO data.

    Art McDonald, who shared that Nobel as director of the SNO Collaboration, said, “The PDSF computing facility was used extensively by the SNO Collaboration, including our collaborators at Berkeley Lab.”

    He added, “This resource was extremely valuable in simulations and data analysis over many years, leading to our breakthroughs in neutrino physics and resulting in the award of the 2015 Nobel Prize and the 2016 Breakthrough Prize in Fundamental Physics to the entire SNO Collaboration. We are very grateful for the scientific opportunities provided to us through access to the PDSF facility.”

    PDSF’s fast processing of data from the Daya Bay nuclear reactor-based experiment was also integral in precise measurements of neutrino properties.

    The cluster was a trendsetter for a so-called condo model in shared computing. This model allowed collaborations to buy a share of computing power and dedicated storage space that was customized for their own needs, and a participant’s allocated computer processors on the system could also be temporarily co-opted by other cluster participants when they were not active.

    In this condo analogy, “You could go use your neighbor’s house if your neighbor wasn’t using it,” said Canon, a former experimental physicist. “If everybody else was idle you could take advantage of the free capacity.” Canon noted that many universities have adopted this kind of model for their computer users.

    Importantly, the PDSF system was also designed to provide easy access and support for individual collaboration members rather than requiring access to be funneled through one account per project or experiment. “If everybody had to log in to submit their jobs, it just wouldn’t work in these big collaborations,” Canon said.

    The original PDSF cluster, called the Physics Detector Simulation Facility, was launched in March 1991 to support analyses and simulations for a planned U.S. particle collider project known as the Superconducting Super Collider. It was set up in Texas, the planned home for the collider, though the collider project was ultimately canceled in 1993.

    Superconducting Super Collider map, in the vicinity of Waxahachie, Texas, Cancelled by The U.S. Congress in 1993 because it showed no “immediate economic benefit”

    5
    A diagram showing the Phase 3 design of the original PDSF system. (Credit: “Superconducting Super Collider: A Retrospective Summary 1989-1993,” Superconducting Super Collider Laboratory, Dallas, Texas)

    A 1994 retrospective report on the collider project notes that the original PDSF had been built up to perform a then-impressive 7 billion instructions per second and that the science need for PDSF to simulate complex particle collisions had driven “substantial technological advances” in the nation’s computer industry.

    At the time, PDSF was “the world’s most powerful high-energy physics computing facility,” the report also noted, and was built using non-proprietary systems and equipment from different manufacturers “at a fraction of the cost” of supercomputers.

    Longtime Berkeley Lab physicist Stu Loken, who had led the Lab’s Information and Computing Sciences Division from 1988-2000, had played a pivotal role in PDSF’s development and in siting the cluster at Berkeley Lab.

    7
    PDSF moved to Berkeley Lab’s Oakland Scientific Facility in 2000 before returning to the lab’s main site. (Credit: Berkeley Lab)

    PDSF moved to Berkeley Lab in 1996 with a new name and a new role. It was largely rebuilt with new hardware and was moved to a computer center in Oakland, Calif., in 2000 before returning once again to the Berkeley Lab site.

    “A lot of the tools that we deployed to facilitate the data processing on PDSF are now being used by data users at NERSC,” said Lisa Gerhardt, a big-data architect at NERSC who worked on the PDSF system. She previously had served as a neutrino astrophysicist for the IceCube experiment.

    Gerhardt noted that the cluster was nimble and responsive because of its focused user community. “Having a smaller and cohesive user pool made it easier to have direct relationships,” she said.

    And Jan Balewski, computing systems engineer at NERSC who worked to transition PDSF users to the new system, said the scientific background of PDSF staff through the years was beneficial for the cluster’s users.

    Balewski, a former experimental physicist, said, “Having our background, we were able to discuss with users what they really needed. And maybe, in some cases, what they were asking for was not what they really needed. We were able to help them find a solution.”

    R. Jefferson “Jeff” Porter, a computer systems engineer and physicist in Berkeley Lab’s Nuclear Science Division who began working with the PDSF cluster and users as a postdoctoral researcher at Berkeley Lab in the mid-1990s, said, “PDSF was a resource that dealt with big data – many years before big data became a big thing for the rest of the world.”

    It had always used off-the-shelf hardware and was steadily upgraded – typically twice a year. Even so, it was dwarfed by its supercomputer counterparts. About seven years ago the PDSF cluster had about 1,500 computer cores, compared to about 100,000 on a neighboring supercomputer at NERSC at the time. A core is the part of a computer processor that performs calculations

    Porter was later hired by NERSC to support grid computing, a distributed form of computing in which computers in different locations can work together to perform larger tasks. He returned to the Nuclear Science Division to lead the ALICE USA computing project, which established PDSF as one of about 80 grid sites for CERN’s ALICE experiment. Use of PDSF by ALICE was an easy fit, since the PDSF community “was at the forefront of grid computing,” Porter said.

    In some cases, the unique demands of PDSF cluster users would also lead to the adoption of new tools at supercomputer systems. “Our community would push NERSC in ways they hadn’t been thinking,” he said. CERN developed a system to distribute software that was adopted by PDSF about five years ago, and that has also been adopted by many scientific collaborations. NERSC put in a big effort, Porter said, to integrate this system into larger machines: Cori and Edison.

    8
    PDSF’s configuration in 2017. (Credit: Berkeley Lab)

    Supporting multiple projects on a single system was a challenge for PDSF since each project had unique software needs, so Canon led the development of a system known as Chroot OS (CHOS) to enable each project to have a custom computing environment.

    Porter explained that CHOS was an early form of “container computing” that has since enjoyed widespread adoption.

    PDSF was run by a Berkeley Lab-based steering committee that typically had a member from each participating experiment and a member from NERSC, and Porter had served for about five years as the committee chair. He had been focused for the past year on how to transition users to the Cori supercomputer and other computing resources, as needed.

    Balewski said that the leap of users from PDSF to Cori brings them access to far greater computing power, and allows them to “ask questions they could never ask on a smaller system.”

    He added, “It’s like moving from a small town – where you know everyone but resources are limited – to a big city that is more crowded but also offers more opportunities.”

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Bringing Science Solutions to the World

    In the world of science, Lawrence Berkeley National Laboratory (Berkeley Lab) is synonymous with “excellence.” Thirteen Nobel prizes are associated with Berkeley Lab. Seventy Lab scientists are members of the National Academy of Sciences (NAS), one of the highest honors for a scientist in the United States. Thirteen of our scientists have won the National Medal of Science, our nation’s highest award for lifetime achievement in fields of scientific research. Eighteen of our engineers have been elected to the National Academy of Engineering, and three of our scientists have been elected into the Institute of Medicine. In addition, Berkeley Lab has trained thousands of university science and engineering students who are advancing technological innovations across the nation and around the world.

    Berkeley Lab is a member of the national laboratory system supported by the U.S. Department of Energy through its Office of Science. It is managed by the University of California (UC) and is charged with conducting unclassified research across a wide range of scientific disciplines. Located on a 202-acre site in the hills above the UC Berkeley campus that offers spectacular views of the San Francisco Bay, Berkeley Lab employs approximately 3,232 scientists, engineers and support staff. The Lab’s total costs for FY 2014 were $785 million. A recent study estimates the Laboratory’s overall economic impact through direct, indirect and induced spending on the nine counties that make up the San Francisco Bay Area to be nearly $700 million annually. The Lab was also responsible for creating 5,600 jobs locally and 12,000 nationally. The overall economic impact on the national economy is estimated at $1.6 billion a year. Technologies developed at Berkeley Lab have generated billions of dollars in revenues, and thousands of jobs. Savings as a result of Berkeley Lab developments in lighting and windows, and other energy-efficient technologies, have also been in the billions of dollars.

    Berkeley Lab was founded in 1931 by Ernest Orlando Lawrence, a UC Berkeley physicist who won the 1939 Nobel Prize in physics for his invention of the cyclotron, a circular particle accelerator that opened the door to high-energy physics. It was Lawrence’s belief that scientific research is best done through teams of individuals with different fields of expertise, working together. His teamwork concept is a Berkeley Lab legacy that continues today.

    A U.S. Department of Energy National Laboratory Operated by the University of California.

    University of California Seal

    DOE Seal

     
  • richardmitnick 5:30 pm on April 18, 2019 Permalink | Reply
    Tags: , Handedness, LBNL, , , Skyrmions – quasiparticles akin to tiny magnetic swirls,   

    From Lawrence Berkeley National Lab: “Electric Skyrmions Charge Ahead for Next-Generation Data Storage” 

    Berkeley Logo

    From Lawrence Berkeley National Lab

    April 18, 2019
    Theresa Duque
    tnduque@lbl.gov
    (510) 495-2418

    Berkeley Lab-led research team makes a chiral skyrmion crystal with electric properties; puts new spin on future information storage applications.


    VIDEO: Simulation of a single polar skyrmion. Red arrows signify that this is a left-handed skyrmion. The other arrows represent the angular distribution of the dipoles. (Credit: Xiaoxing Cheng, Pennsylvania State University; C.T. Nelson, Oak Ridge National Laboratory; and Ramamoorthy Ramesh, Berkeley Lab)

    When you toss a ball, what hand do you use? Left-handed people naturally throw with their left hand, and right-handed people with their right. This natural preference for one side versus the other is called handedness, and can be seen almost everywhere – from a glucose molecule whose atomic structure leans left, to a dog who shakes “hands” only with her right.

    Handedness can be exhibited in chirality – where two objects, like a pair of gloves, can be mirror images of each other but cannot be superimposed on one another. Now a team of researchers led by Berkeley Lab has observed chirality for the first time in polar skyrmions – quasiparticles akin to tiny magnetic swirls – in a material with reversible electrical properties. The combination of polar skyrmions and these electrical properties could one day lead to applications such as more powerful data storage devices that continue to hold information – even after a device has been powered off. Their findings were reported this week in the journal Nature.

    “What we discovered is just mind-boggling,” said Ramamoorthy Ramesh, who holds appointments as a faculty senior scientist in Berkeley Lab’s Materials Sciences Division and as the Purnendu Chatterjee Endowed Chair in Energy Technologies in Materials Science and Engineering and Physics at UC Berkeley. “We hadn’t planned on making skyrmions. So for us to end up making a chiral skyrmion is exciting.”

    1

    When the team of researchers – co-led by Ramesh and Lane Martin, a staff scientist in Berkeley Lab’s Materials Sciences Division and a professor in Materials Science and Engineering at UC Berkeley – began this study in 2016, they had set out to find ways to control how heat moves through materials. So they fabricated a special crystal structure called a superlattice from alternating layers of lead titanate (an electrically polar material, whereby one end is positively charged and the opposite end is negatively charged) and strontium titanate (an insulator, or a material that doesn’t conduct electric current).

    But once they took STEM (scanning transmission electron microscopy) measurements of the lead titanate/strontium titanate superlattice at the Molecular Foundry, a U.S. DOE Office of Science User Facility at Berkeley Lab that specializes in nanoscale science, they saw something strange that had nothing to do with heat: Bubble-like formations had cropped up all across the device.

    Bubbles, bubbles everywhere

    So what were these “bubbles,” and how did they get there?

    Those bubbles, it turns out, were polar skyrmions – or textures made up of opposite electric charges known as dipoles. Researchers had always assumed that skyrmions would only appear in magnetic materials, where special interactions between magnetic spins of charged electrons stabilize the twisting chiral patterns of skyrmions. So when the Berkeley Lab-led team of researchers discovered skyrmions in an electric material, they were astounded.

    3
    Simulation of the cross-section in the middle of the polar-skyrmion bubble. (Credit: Berkeley Lab)

    Through the researchers’ collaboration with theorists Javier Junquera of the University of Cantabria in Spain, and Jorge Íñiguez of the Luxembourg Institute of Science and Technology, they discovered that these textures had a unique feature called a “Bloch component” that determined the direction of its spin, which Ramesh compares to the fastening of a belt – where if you’re left-handed, the belt goes from left to right. “And it turned out that this Bloch component – the skyrmion’s equatorial belt, so to speak – is the key to its chirality or handedness,” he said.

    While using sophisticated STEM at Berkeley Lab’s Molecular Foundry and at the Cornell Center for Materials Research, where David Muller of Cornell University took atomic snapshots of skyrmions’ chirality at room temperature in real time, the researchers discovered that the forces placed on the polar lead titanate layer by the nonpolar strontium titanate layer generated the polar skyrmion “bubbles” in the lead titanate.

    “Materials are like people,” said Ramesh. “When people get stressed, they respond in unpredictable ways. And that’s what materials do too: In this case, by surrounding lead titanate by strontium titanate, lead titanate starts to go crazy – and one way that it goes crazy is to create polar textures like skyrmions.”

    Through the researchers’ collaboration with theorists Javier Junquera of the University of Cantabria in Spain, and Jorge Íñiguez of the Luxembourg Institute of Science and Technology, they discovered that these textures had a unique feature called a “Bloch component” that determined the direction of its spin, which Ramesh compares to the fastening of a belt – where if you’re left-handed, the belt goes from left to right. “And it turned out that this Bloch component – the skyrmion’s equatorial belt, so to speak – is the key to its chirality or handedness,” he said.

    While using sophisticated STEM at Berkeley Lab’s Molecular Foundry and at the Cornell Center for Materials Research, where David Muller of Cornell University took atomic snapshots of skyrmions’ chirality at room temperature in real time, the researchers discovered that the forces placed on the polar lead titanate layer by the nonpolar strontium titanate layer generated the polar skyrmion “bubbles” in the lead titanate.

    Custom-designed scanning transmission electron microscope at Cornell University by David Muller/Cornell University

    LBNL THEMIS scannng transmission electronic micsoscope

    “Materials are like people,” said Ramesh. “When people get stressed, they respond in unpredictable ways. And that’s what materials do too: In this case, by surrounding lead titanate by strontium titanate, lead titanate starts to go crazy – and one way that it goes crazy is to create polar textures like skyrmions.”

    Shining a light on crystal chirality

    To confirm their observations, senior staff scientist Elke Arenholz and staff scientist Padraic Shafer at Berkeley Lab’s Advanced Light Source (ALS), along with Margaret McCarter, a physics Ph.D. student from the Ramesh Lab at UC Berkeley, probed the chirality by using a spectroscopic technique known as RSXD-CD (resonant soft X-ray diffraction circular dichroism), one of the highly optimized tools available to the scientific community at the ALS, a U.S. DOE Office of Science User Facility that specializes in lower energy, “soft” X-ray light for studying the properties of materials.

    LBNL ALS

    3
    Simulations of skyrmion bubbles and elongated skyrmions for the lead titanate/strontium titanate superlattice. (Credit: Berkeley Lab)

    Light waves can be “circularly polarized” to also have handedness, so the researchers theorized that if polar skyrmions have handedness, a left-handed skyrmion, for example, should interact more strongly with left-handed, circularly polarized light – an effect known as circular dichroism.

    When McCarter and Shafer tested the samples at the ALS, they successfully uncovered another piece to the chiral skyrmion puzzle – they found that incoming circularly polarized X-rays, like a screw whose threads rotate either clockwise or counterclockwise, interact with skyrmions whose dipoles rotate in the same direction, even at room temperature. In other words, they found evidence of circular dichroism – where there is only a strong interaction between X-rays and polar skyrmions with the same handedness.

    “The theoretical simulations and microscopy both revealed the presence of a Bloch component, but to confirm the chiral nature of these skyrmions, the last piece of the puzzle was really the circular dichroism measurements,” McCarter said. “It is amazing to observe this effect in materials that typically don’t have handedness. We are excited to explore the implications of this chirality in a ferroelectric and how it can be controlled in a way that could be useful for storing data.”

    Now that the researchers have made a single electric skyrmion and confirmed its chirality, they plan to make an array of dozens of electric skyrmions – each one with a diameter of just 8 nm (for comparison, the Ebola virus is about 50 nm wide) – with the same handedness. “In terms of applications, this is exciting because now we have chirality – switching a skyrmion on or off, or between left-handed and right-handed – on top of still being able to use the charge for storing data,” Ramesh said.

    The researchers next plan to study the effects of applying an electric field on the polar skyrmions. “Now that we know that polar/electric skyrmions are chiral, we want to see if we can electrically manipulate them. If I apply an electric field, can I turn each one like a turnstile? Can I move each one, one at a time, like a checker on a checkerboard? If we can somehow move them, write them, and erase them for data storage, then that would be an amazing new technology,” Ramesh said.

    Also contributing to the study were researchers from Pennsylvania State University, Cornell University, and Oak Ridge National Laboratory.

    The work was supported by the DOE Office of Science with additional funding provided by the Gordon and Betty Moore Foundation’s EPiQS Initiative, the National Science Foundation, the Luxembourg National Research Fund, and the Spanish Ministry of Economy and Competitiveness.

    See the full article here .

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    In the world of science, Lawrence Berkeley National Laboratory (Berkeley Lab) is synonymous with “excellence.” Thirteen Nobel prizes are associated with Berkeley Lab. Seventy Lab scientists are members of the National Academy of Sciences (NAS), one of the highest honors for a scientist in the United States. Thirteen of our scientists have won the National Medal of Science, our nation’s highest award for lifetime achievement in fields of scientific research. Eighteen of our engineers have been elected to the National Academy of Engineering, and three of our scientists have been elected into the Institute of Medicine. In addition, Berkeley Lab has trained thousands of university science and engineering students who are advancing technological innovations across the nation and around the world.

    Berkeley Lab is a member of the national laboratory system supported by the U.S. Department of Energy through its Office of Science. It is managed by the University of California (UC) and is charged with conducting unclassified research across a wide range of scientific disciplines. Located on a 202-acre site in the hills above the UC Berkeley campus that offers spectacular views of the San Francisco Bay, Berkeley Lab employs approximately 3,232 scientists, engineers and support staff. The Lab’s total costs for FY 2014 were $785 million. A recent study estimates the Laboratory’s overall economic impact through direct, indirect and induced spending on the nine counties that make up the San Francisco Bay Area to be nearly $700 million annually. The Lab was also responsible for creating 5,600 jobs locally and 12,000 nationally. The overall economic impact on the national economy is estimated at $1.6 billion a year. Technologies developed at Berkeley Lab have generated billions of dollars in revenues, and thousands of jobs. Savings as a result of Berkeley Lab developments in lighting and windows, and other energy-efficient technologies, have also been in the billions of dollars.

    Berkeley Lab was founded in 1931 by Ernest Orlando Lawrence, a UC Berkeley physicist who won the 1939 Nobel Prize in physics for his invention of the cyclotron, a circular particle accelerator that opened the door to high-energy physics. It was Lawrence’s belief that scientific research is best done through teams of individuals with different fields of expertise, working together. His teamwork concept is a Berkeley Lab legacy that continues today.

    A U.S. Department of Energy National Laboratory Operated by the University of California.

    University of California Seal

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    • Arushi 6:58 am on April 19, 2019 Permalink | Reply

      Your blog seems pretty informative. Instead of just NASA can you write about the discoveries of other organizations as well so that the science lovers can get every aspect of physics in your blog? BTW love your blog💝

      Like

      • richardmitnick 3:31 pm on April 19, 2019 Permalink | Reply

        I cover much more than NASA. I cover universities and science institutions all over the world. There is a concentration on Astronomy and Physics, but I also cover volcanology, earthquake science, ASD, HPC, . What you need to do is read the blog or access the Facebook Fan page, http://facebook.com/sciencesprings which is a pretty rich experience if you do not want to bother seeing the blog posts in full.

        Like

        • Arushi 5:15 pm on April 19, 2019 Permalink

          Okay buddy. I’m not much into science but I surely do find physics and astronomy pretty interesting. I’ll check out your Facebook page for sure.

          Like

        • richardmitnick 7:20 pm on April 21, 2019 Permalink

          Thanks.

          Like

  • richardmitnick 12:49 pm on April 3, 2019 Permalink | Reply
    Tags: , , , Collaborating Institutions - Member Institutions and representatives, , , LBNL   

    From Lawrence Berkeley National Lab: “Dark Energy Instrument’s Lenses See the Night Sky for the First Time” 

    Berkeley Logo

    From Lawrence Berkeley National Lab

    April 3, 2019
    Glenn Roberts Jr.

    LBNL/DESI spectroscopic instrument on the Mayall 4-meter telescope at Kitt Peak National Observatory starting in 2018

    NOAO/Mayall 4 m telescope at Kitt Peak, Arizona, USA, Altitude 2,120 m (6,960 ft)

    Kitt Peak National Observatory of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono O’odham Nation, 88 kilometers 55 mi west-southwest of Tucson, Arizona, Altitude 2,096 m (6,877 ft)

    1
    DESI “first light” image of the Whirlpool Galaxy, also known as Messier 51. This image was obtained the first night of observing with the DESI Commissioning Instrument on the Mayall Telescope at the Kitt Peak National Observatory in Tucson, Arizona; an r-band filter was used to capture the red light from the galaxy. (Credit: DESI Collaboration)

    On April 1, the dome of the Mayall Telescope near Tucson, Arizona, opened to the night sky, and starlight poured through the assembly of six large lenses that were carefully packaged and aligned for a new instrument that will launch later this year.

    Just hours later, scientists produced the first focused images with these precision lenses – the largest is 1.1 meters in diameter – during this early test spin, marking an important “first light” milestone for the Dark Energy Spectroscopic Instrument, or DESI. This first batch of images homed in on the Whirlpool Galaxy to demonstrate the quality of the new lenses.

    ”It was an incredible moment to see those first images on the control room monitors,” said Connie Rockosi, who is leading this early commissioning of the DESI lenses. “A whole lot of people have worked really hard on this, and it’s really exciting to show how much has come together already.”

    This phase of the project will continue for about six weeks and will require the efforts of several onsite scientists and remote observers, noted Rockosi, a professor of astronomy and astrophysics at UC Santa Cruz.

    When completed later this year, DESI will see and measure the sky’s light in a far different way than this assembly of lenses. It is designed to take in thousands of points of light instead of a single, large picture.

    The finished DESI will measure the light of tens of millions of galaxies reaching back 12 billion light-years across the universe. It is expected to provide the most precise measurement of the expansion of the universe and provide new insight into dark energy, which scientists explain is causing this expansion to accelerate.


    In this video, DESI project participants share their insight and excitement about the project and its potential for new and unexpected discoveries. (Credit: Marilyn Chung/Berkeley Lab, DESI Collaboration)

    DESI’s array of 5,000 independently swiveling robotic positioners (see a related video: 5,000 Robots Merge to Map the Universe in 3D), each carrying a thin fiber-optic cable, will automatically move into preset positions with accuracy to within several microns (millionths of a meter). Each positioner is programmed to point its fiber-optic cable at an object to gather its light.

    That light will be channeled through the cables to a series of 10 devices known as spectrographs that will separate the light into thousands of colors. The light measurements, known as spectra, will provide detailed information about objects’ distance and the rate at which they are moving away from us, providing fresh insight about dark energy.

    DESI’s lenses are housed in a barrel-shaped device known as a corrector that is attached above the telescope’s primary mirror, and the corrector is moved and focused by a surrounding device known as a hexapod.

    Fermi National Accelerator Laboratory (Fermilab) researchers led the design, construction, and initial testing of the corrector barrel, hexapod and supporting structures that hold the lenses in alignment.

    “Our entire team is pleased to see this instrument achieve first light,” said Gaston Gutierrez, the Fermilab scientist who managed this part of the project. “It was a great challenge building such large devices to within the precision of a hair. We’re happy to see these systems come together.”

    2
    A view of the lenses in DESI’s corrector. The largest lens measures over a meter across.

    The giant corrector barrel and hexapod, which together weigh about 5 tons, must maintain alignment with the telescope’s large reflector mirror that is 12 meters below, all while compensating for the movement of the telescope’s assemblage of massive components as it swings across the sky.

    “This is a big step up. It’s a leap into the future for the Mayall Telescope that will enable exciting new scientific discoveries,” said Michael Levi, DESI’s director and a physicist at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), which is the lead institution in the international DESI collaboration. “The team has been working on the new corrector for the past five years, so it was quite an experience seeing $10 million of optics lifted by the crane during installation.”

    4
    DESI’s cylindrical commissioning instrument, top left, sits just above the corrector barrel (middle) on the Mayall Telescope. The commissioning instrument is designed to test the performance of DESI’s lenses, which are stacked inside the corrector barrel, using a set of five precisely positioned digital cameras. (Credit: Bill McCollam and Paul Demmer/KPNO, NOAO/AURA/NSF)

    The new set of lenses (see a related video: The Life of a Lens) expands the telescope’s viewing window by about 16 times, enabling DESI to map about one-third of the visible sky several times during its five-year mission.

    Peter Doel, a professor at University College London, led the team that designed the new optical system. “We had a half-dozen vendors involved with making and polishing the glass. One mistake would have spoiled everything. It’s thrilling to know that they survived the journey and work so well.”

    “This was kind of the moment of truth,” said David Schlegel, a DESI project scientist. “We have been biting our nails.”

    David Sprayberry, the National Optical Astronomy Observatory (NOAO) site director at Kitt Peak, said, “We have an amazing, multitalented team to make sure that everything is working properly,” including engineers, astronomers, and telescope operators working in shifts. NOAO operates the Mayall Telescope and its Kitt Peak National Observatory site.

    He noted the challenge in updating the sturdy, decades-old telescope, which started up in 1973, with high-precision equipment. “Ultimately we must make sure DESI can target to within 5-micron accuracy – not much larger than a human hair,” he said. That’s a big thing for something so heavy and big.” The entire moving weight of the Mayall Telescope is 375 tons.

    Rockosi said there was intensive pre-planning for the corrector’s early testing, and many of the tasks during this testing stage are focused on gathering data from evening observations. While DESI scientists have created automated controls to help position, focus, and align all of the equipment, this testing run allows the team to fine-tune these automated tools.

    “We’ll look at bright stars and test how well we can keep the telescope targeted in the same place, and measure image quality,” Rockosi said. “We will test that we can repeatedly and reliably keep those lenses in the best possible alignment.”

    5
    Paul Martini, an astronomy professor at Ohio State University, inspects DESI’s commissioning instrument before it is installed on the 4-meter Mayall Telescope at Kitt Peak National Observatory. (Credit: NOAO/AURA/NSF)

    The precision testing of the corrector is made possible by an instrument – now mounted atop the telescope – that was designed and built by Ohio State University researchers. This 1-ton device, which features five digital cameras and measuring tools supplied by Yale University, and electronics supplied by the University of Michigan, is known as the commissioning instrument.

    6
    Workers raise DESI’s commissioning instrument into position for installation. The instrument is designed to test the performance of DESI’s lenses. (Credit: NOAO/AURA/NSF)

    This temporary instrument was built at the same weight and installed at the same spot where DESI’s focal plane will be installed once it is fully assembled. The focal plane will carry DESI’s robotic positioners. The commissioning instrument simulates how the telescope will perform when carrying the full complement of DESI components, and is verifying the quality of DESI’s lenses.

    “One of the biggest challenges with the commissioning instrument was aligning all five cameras with the corrector’s curved focal surface,” said Paul Martini, an astronomy professor at Ohio State University who led the R&D and installation of the commissioning instrument and is now overseeing its use. “Another was measuring their positions to a few millionths of a meter, which is far more precise than most astronomical instruments.” This positioning will ensure truer measurements of the lenses’ performance.

    He said he is looking forward to the installation of DESI’s focal plane later this year. That will pave the way for DESI’s official “first light” of its robotic positioners and the start of its galaxy measurements.

    “What got me excited about this field in the first place was going to telescopes and taking data, so it will be fun to have this next step,” he said.

    DESI is supported by the U.S. Department of Energy’s Office of Science; the U.S. National Science Foundation, Division of Astronomical Sciences under contract to the National Optical Astronomy Observatory; the Science and Technologies Facilities Council of the United Kingdom; the Gordon and Betty Moore Foundation; the Heising-Simons Foundation; the National Council of Science and Technology of Mexico; the Ministry of Economy of Spain; and DESI member institutions. The DESI scientists are honored to be permitted to conduct astronomical research on Iolkam Du’ag (Kitt Peak), a mountain with particular significance to the Tohono O’odham Nation. View the full list of DESI collaborating institutions, and learn more about DESI here: http://www.desi.lbl.gov.

    Collaborating Institutions
    Member Institutions and representatives:

    Argonne National Laboratory – Salman Habib
    Barcelona – Madrid RPG – Francisco Castander
    Boston University – Steve Ahlen
    Brookhaven National Laboratory – Anze Slosar
    Carnegie Mellon University – Shirley Ho
    Cornell University – Rachel Bean
    École Polytechnique Fédérale de Lausanne (EPFL)– Jean-Paul Kneib
    Eidgenössische Technische Hochschule Zürich (ETHZ) – Alexandre Refregier
    Fermi National Accelerator Laboratory – Elizabeth Buckley-Geer
    GMT RPG – Francisco Prada
    Harvard University – Daniel Eisenstein
    Korea Astronomy and Space Science Institute (KASI) – Yong-Seon Song
    Korea Institute for Advanced Study (KIAS) – Changbom Park
    Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE) – Julien Guy
    Lawrence Berkeley National Laboratory – David Schlegel
    LinEA-Brazil – Luiz da Costa
    Max Planck Institut fur Extraterrestriche Physik – Ariel Sanchez
    Mexico RPG – Axel de la Macorra
    National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) – Shude Mao
    National Optical Astronomy Observatory – Robert Blum
    Ohio State University – Klaus Honscheid
    Ohio University – Hee-Jong Seo
    Shanghai Jiao Tong University – Ying Zu
    Siena College – John Moustakas
    SLAC National Accelerator Laboratory – Aaron Roodman
    Southern Methodist University – Bob Kehoe
    Swinburne University of Technology – Chris Blake
    UK RPG – John Peacock
    Universidad de los Andes – Jamie Forero
    Universitat de Barcelona – Licia Verde
    Université Aix-Marseille (AMU) – Jean-Gabriel Cuby
    University College London – Ofer Lahav
    University of Arizona – Xiaohui Fan
    University of California, Berkeley – Jerry Edelstein
    University of California, Irvine – David Kirkby
    University of California, Santa Cruz – Connie Rockosi
    University of Durham – Carlos Frenk
    University of Michigan – Gregory Tarle
    University of Paris Saclay – Christophe Yeche
    University of Pennsylvania – Adam Lidz
    University of Pittsburgh – Jeffrey Newman
    University of Portsmouth – Will Percival
    University of Queensland – Tamara Davis
    University of Rochester – Regina Demina
    University of Toronto – Ray Carlberg
    University of Utah – Kyle Dawson
    University of Wyoming – Adam Myers
    Yale University – Charles Baltay

    See the full article here .

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    Please help promote STEM in your local schools.

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    In the world of science, Lawrence Berkeley National Laboratory (Berkeley Lab) is synonymous with “excellence.” Thirteen Nobel prizes are associated with Berkeley Lab. Seventy Lab scientists are members of the National Academy of Sciences (NAS), one of the highest honors for a scientist in the United States. Thirteen of our scientists have won the National Medal of Science, our nation’s highest award for lifetime achievement in fields of scientific research. Eighteen of our engineers have been elected to the National Academy of Engineering, and three of our scientists have been elected into the Institute of Medicine. In addition, Berkeley Lab has trained thousands of university science and engineering students who are advancing technological innovations across the nation and around the world.

    Berkeley Lab is a member of the national laboratory system supported by the U.S. Department of Energy through its Office of Science. It is managed by the University of California (UC) and is charged with conducting unclassified research across a wide range of scientific disciplines. Located on a 202-acre site in the hills above the UC Berkeley campus that offers spectacular views of the San Francisco Bay, Berkeley Lab employs approximately 3,232 scientists, engineers and support staff. The Lab’s total costs for FY 2014 were $785 million. A recent study estimates the Laboratory’s overall economic impact through direct, indirect and induced spending on the nine counties that make up the San Francisco Bay Area to be nearly $700 million annually. The Lab was also responsible for creating 5,600 jobs locally and 12,000 nationally. The overall economic impact on the national economy is estimated at $1.6 billion a year. Technologies developed at Berkeley Lab have generated billions of dollars in revenues, and thousands of jobs. Savings as a result of Berkeley Lab developments in lighting and windows, and other energy-efficient technologies, have also been in the billions of dollars.

    Berkeley Lab was founded in 1931 by Ernest Orlando Lawrence, a UC Berkeley physicist who won the 1939 Nobel Prize in physics for his invention of the cyclotron, a circular particle accelerator that opened the door to high-energy physics. It was Lawrence’s belief that scientific research is best done through teams of individuals with different fields of expertise, working together. His teamwork concept is a Berkeley Lab legacy that continues today.

    A U.S. Department of Energy National Laboratory Operated by the University of California.

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  • richardmitnick 1:52 pm on March 20, 2019 Permalink | Reply
    Tags: A particularly interesting property of the studied crystals is that they can produce an electrical current of a fixed strength when you shine a light on them, , , In this new work we are essentially proving that this is a new state of quantum matter, LBNL, Topological chiral crystals, Topological materials – which exhibit exotic defect-resistant properties, Topologically protected means that some of the material’s properties are reliably constant even if the material is not perfect   

    From Lawrence Berkeley National Lab: “The Best Topological Conductor Yet: Spiraling Crystal Is the Key to Exotic Discovery” 

    Berkeley Logo

    From Lawrence Berkeley National Lab

    March 20, 2019
    Glenn Roberts Jr.
    geroberts@lbl.gov
    (510) 486-5582

    1
    This animation shows how Fermi arc states form a spiraling structure in a crystal material that serves as a topological conductor. (Credit: Hasan Lab/Princeton University)


    The realization of so-called topological materials – which exhibit exotic, defect-resistant properties and are expected to have applications in electronics, optics, quantum computing, and other fields – has opened up a new realm in materials discovery.

    Several of the hotly studied topological materials to date are known as topological insulators. Their surfaces are expected to conduct electricity with very little resistance, somewhat akin to superconductors but without the need for incredibly chilly temperatures, while their interiors – the so-called “bulk” of the material – do not conduct current.

    Now, a team of researchers working at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) has discovered the strongest topological conductor yet, in the form of thin crystal samples that have a spiral-staircase structure. The team’s study of crystals, dubbed topological chiral crystals, is reported in the March 20 edition of the journal Nature.

    2
    The spiraling, chiral structure of crystals containing rhodium and silicon. (Credit: Hasan Lab/Princeton University)

    The DNA-like spiraling structure, or helicoid, in the crystal sample that was the focus of the latest study exhibits a chirality or “handedness” – as a person can be either left-handed or right-handed, and the left hand is a mirror image of the right hand. Chiral properties in some cases can be flipped, like a left-handed person becoming a right-handed person.

    “In this new work we are essentially proving that this is a new state of quantum matter, which is also exhibiting nearly ideal topological surface properties that emerge as a consequence of the chirality of crystal structure,” said M. Zahid Hasan, a topological materials pioneer who led the materials theory and experiments as a visiting faculty scientist in the Materials Sciences Division at Berkeley Lab. Hasan is also the Eugene Higgins Professor of Physics at Princeton University.

    A property that defines topological conductivity – which is related to the electrical conductivity of the material’s surface – was measured to be about 100 times larger than that observed in previously identified topological metals.

    This property, known as the surface Fermi arc, was revealed in X-ray experiments at Berkeley Lab’s Advanced Light Source (ALS) using a technique known as photoemission spectroscopy. The ALS is a synchrotron that produces intense light – from infrared to high-energy X-rays – for dozens of simultaneous experiments.

    LBNL ALS

    Topology is a well-established mathematical concept that relates to the preservation of an object’s geometrical properties even if an object is stretched or deformed in other ways. Some of its experimental applications in 3D electronic materials – such as discovering topological behaviors in materials’ electronic structures – were only realized just over a decade ago, with early and continuing contributions by Berkeley Lab.

    “After more than 12 years of research in topological physics and materials, I do believe that this is only the tip of the iceberg,” Hasan added. “Based on our measurements, this is the most robust, topologically protected conductor metal that anybody has discovered – it is taking us to a new frontier.”

    Topologically protected means that some of the material’s properties are reliably constant even if the material is not perfect. That quality also bolsters the future possibility of practical applications and manufacturability for these types of materials.

    Ilya Belopolski, a Princeton researcher who participated in both the theory and experimental work, noted that a particularly interesting property of the studied crystals – which included cobalt-silicon and rhodium-silicon crystals – is that they can produce an electrical current of a fixed strength when you shine a light on them.

    “Our previous theories showed that – based on the material’s electronic properties that we have now observed – the current would be fixed at specific values,” he said. “It doesn’t matter how big the sample is, or if it’s dirty. It is a universal value. That’s amazing. For applications, the performance will be the same.”

    4
    Princeton University Professor Zahid Hasan, right, describes the exotic behavior of electrons in topological crystals that were studied at Berkeley Lab. Members of Hasan’s research team observe, including: Daniel S. Sanchez (left), Ilya Belopolski (standing, middle), and Tyler A. Cochran (seated, middle). (Credit: Marilyn Chung/Berkeley Lab)

    In previous experiments at the ALS, Hasan’s team had revealed the existence of a type of massless quasiparticles known as Weyl fermions, which had only been known to exist in theory for about 85 years.

    The Weyl fermions, which were observed in synthetic crystals of a semimetal called tantalum arsenide, exhibit some similar electronic properties to those found in the crystals used in the latest study, but lacked their chiral traits. Semimetals are materials that have some metal and some non-metal properties.

    “Our earlier work on Weyl semimetals paved the path for research on exotic topological conductors,” said Hasan. In an November 2017 study that focused on theory surrounding these exotic materials, Hasan’s team predicted that electrons in rhodium-silicon and many related materials behaved in highly unusual ways.

    The team had predicted that quasiparticles in the material – described by the collective motion of electrons – emerge like massless electrons and should behave like slowed, 3D particles of light, with definite handedness or chirality traits unlike in topological insulators or graphene.

    Also, their calculations, published Oct. 1, 2018 in the Nature Materials journal, suggested that electrons in the crystals would collectively behave as if they are magnetic monopoles in their motion. Magnetic monopoles are hypothetical particles with a single magnetic pole – like the Earth without a South Pole that can move independent of a North Pole.

    4
    A simulation showing the spiral structure of Fermi arc properties across different layers of cobalt-silicon crystal samples. (Credit: Hasan Lab/Princeton University)

    All of this unusual topological behavior points back toward the chiral nature of the crystal samples, which create a spiral or “helicoidal” electronic structure, as observed in the experiments, Hasan noted.

    The studied samples, which contain crystals measuring up to a couple of millimeters across, were prepared in advance by several international sources. The crystals were characterized by Hasan’s group at Princeton’s Laboratory for Topological Quantum Matter and Advanced Spectroscopy using a low-temperature scanning tunneling microscope that can scan samples at the atomic scale, and the samples were then transported to Berkeley Lab.

    Prior to study at the ALS, the samples underwent a specialized polishing treatment at Berkeley Lab’s Molecular Foundry, a nanoscale science research facility.

    LBNL Molecular Foundry

    Daniel Sanchez and Tyler Cochran, Princeton researchers who contributed to the study, said that samples for such studies are typically “cleaved,” or broken so that they are atomically flat.

    But in this case, the crystal bonds were very strong because the crystals have a cubic shape. So team members worked with staff at the Molecular Foundry to shoot high-energy argon atoms at the crystal samples to clean and flatten them, and then recrystallized and polished the samples through a heating process.

    The researchers used two different X-ray beamlines at the ALS (Beamline 10.0.1 and Beamline 4.0.3) to uncover the unusual electronic and spin properties of the crystal samples.

    Because the electronic behavior in the samples seems to mimic the chirality in the structure of the crystals, Hasan said there are many other avenues to explore, such as testing whether superconductivity can be transferred across other materials to the topological conductor.

    “This could lead to a new type of superconductor,” he said, “or the exploration of a new quantum effect. Is it possible to have a chiral topological superconductor?”

    Also, while the topological properties observed in rhodium-silicon and cobalt-silicon crystals in the latest study are considered ideal, there are many other materials that have been identified that could be studied to gauge their potential for improved performance for real-world applications, Hasan said.

    “It turns out the same physics might also be possible to realize in other compounds in the future that are more suitable for devices,” he said.

    “It is an immense satisfaction when you predict something exotic and it also appears in the laboratory experiments,” Hasan added, noting his team’s prior successes in predicting the topological properties of materials. “With definitive theoretical predictions, we have combined theory and experiments to advance the knowledge frontier.”

    The Advanced Light Source and Molecular Foundry are DOE Office of Science User Facilities.

    Researchers from Rigetti Quantum Computing; Louisiana State University; Peking University, the Collaborative Innovation Center of Quantum Matter, and the University of Chinese Academy of Science in China; the Max Planck Institute for Chemical Physics of Solids in Germany; and Academia Sinica and National Cheng Kung University in Taiwan also participated in this study.

    This work was supported by the U.S. Department of Energy’s Office of Science, the National Natural Science Foundation of China, the National Key R&D Program of China, the Key Research Program of the Chinese Academy of Science, Academia Sinica’s Innovative Materials and Analysis Technology Exploration program, the Ministry of Science and Technology in Taiwan’s Young Scholar Fellowship Program, National Cheng Kung University in Taiwan, the National Center for Theoretical Sciences in Taiwan, the ERC Advanced Grant, and the UC Berkeley Miller Institute of Basic Research in Science’s Visiting Miller Professorship.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Bringing Science Solutions to the World

    In the world of science, Lawrence Berkeley National Laboratory (Berkeley Lab) is synonymous with “excellence.” Thirteen Nobel prizes are associated with Berkeley Lab. Seventy Lab scientists are members of the National Academy of Sciences (NAS), one of the highest honors for a scientist in the United States. Thirteen of our scientists have won the National Medal of Science, our nation’s highest award for lifetime achievement in fields of scientific research. Eighteen of our engineers have been elected to the National Academy of Engineering, and three of our scientists have been elected into the Institute of Medicine. In addition, Berkeley Lab has trained thousands of university science and engineering students who are advancing technological innovations across the nation and around the world.

    Berkeley Lab is a member of the national laboratory system supported by the U.S. Department of Energy through its Office of Science. It is managed by the University of California (UC) and is charged with conducting unclassified research across a wide range of scientific disciplines. Located on a 202-acre site in the hills above the UC Berkeley campus that offers spectacular views of the San Francisco Bay, Berkeley Lab employs approximately 3,232 scientists, engineers and support staff. The Lab’s total costs for FY 2014 were $785 million. A recent study estimates the Laboratory’s overall economic impact through direct, indirect and induced spending on the nine counties that make up the San Francisco Bay Area to be nearly $700 million annually. The Lab was also responsible for creating 5,600 jobs locally and 12,000 nationally. The overall economic impact on the national economy is estimated at $1.6 billion a year. Technologies developed at Berkeley Lab have generated billions of dollars in revenues, and thousands of jobs. Savings as a result of Berkeley Lab developments in lighting and windows, and other energy-efficient technologies, have also been in the billions of dollars.

    Berkeley Lab was founded in 1931 by Ernest Orlando Lawrence, a UC Berkeley physicist who won the 1939 Nobel Prize in physics for his invention of the cyclotron, a circular particle accelerator that opened the door to high-energy physics. It was Lawrence’s belief that scientific research is best done through teams of individuals with different fields of expertise, working together. His teamwork concept is a Berkeley Lab legacy that continues today.

    A U.S. Department of Energy National Laboratory Operated by the University of California.

    University of California Seal

    DOE Seal

     
  • richardmitnick 12:27 pm on March 8, 2019 Permalink | Reply
    Tags: "Scientists Take a Deep Dive Into the Imperfect World of 2D Materials", (Raman/photoluminescence spectroscopy) to study how light interacts with the electrons at microscope scales was used, A form of AFM (atomic force microscopy) was used to view structural details approaching the atomic scale, Adam Schwartzberg: “Now that we know what defects we have and what effect they have on the properties of the material we can use this information to reduce or eliminate defects, , “It’s a very big advance to get this electronic structure on small length scales” said Eli Rotenberg, Because research of WS2 and related 2D materials is still in its infancy there are many unknowns about the roles specific types of defects play in these materials, For this study the defects were due to the sample-growth process, LBNL, , Most of the experiments focused on a single flake of tungsten disulfide, NanoARPES which researchers enlisted to probe the 2D samples with X-rays was used in this work, , Researchers from the Berkeley Lab Chemical Sciences Division Aarhus University in Denmark and Montana State University also participated in this study., Researchers hope to control the amount and kinds of atoms that are affected and the locations where these defects are concentrated in the flakes., The defects were largely concentrated around the edges of the flakes a signature of the growth process, The sample used in the study contained microscopic roughly triangular flakes each measuring about 1 to 5 microns (millionths of a meter) across, The team also enlisted a technique known as XPS (X-ray photoelectron spectroscopy) to study the chemical makeup of a sample at very small scales, The various techniques were applied at the Molecular Foundry where the material was synthesized and at the ALS, The X-rays knocked out electrons in the sample allowing researchers to measure their direction and energy, These 2D materials could also be incorporated in new forms of memory storage and data transfer such as spintronics and valleytronics, They were grown atop titanium dioxide crystals using a conventional layering process known as chemical vapor deposition, This revealed nanoscale defects and how the electrons interact with each other.,   

    From Lawrence Berkeley National Lab: “Scientists Take a Deep Dive Into the Imperfect World of 2D Materials” 

    Berkeley Logo

    From Lawrence Berkeley National Lab

    March 8, 2019

    Glenn Roberts Jr.
    geroberts@lbl.gov
    (510) 486-5582

    Berkeley Lab-led team combines several nanoscale techniques to gain new insights on the effects of defects in a well-studied monolayer material.

    1
    This animation displays a scan of arrow-shaped flakes of a 2D material. Samples were scanned across their electron energy, momentum, and horizontal and vertical coordinates using an X-ray-based technique known as nanoARPES at Berkeley Lab’s Advanced Light Source. Red represents the highest intensity measured, followed by orange, yellow, green, and blue, and purple (least intense). (Credit: Roland Koch/Berkeley Lab)

    Nothing is perfect, or so the saying goes, and that’s not always a bad thing. In a study at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), scientists learned how nanoscale defects can enhance the properties of an ultrathin, so-called 2D material.

    They combined a toolbox of techniques to home in on natural, nanoscale defects formed in the manufacture of tiny flakes of a monolayer material known as tungsten disulfide (WS2) and measured their electronic effects in detail not possible before.

    “Usually we say that defects are bad for a material,” said Christoph Kastl, a postdoctoral researcher at Berkeley Lab’s Molecular Foundry and the lead author of the study, published in the journal ACS Nano. “Here they provide functionality.”

    Tungsten disulfide is a well-studied 2D material that, like other 2D materials of its kind, exhibits special properties because of its atomic thinness. It is particularly well-known for its efficiency in absorbing and emitting light, and it is a semiconductor.

    Members of this family of 2D materials could serve as high-efficiency computer transistors and as other electronics components, and they also are prime candidates for use in ultrathin, high-efficiency solar cells and LED lighting, as well as in quantum computers.

    These 2D materials could also be incorporated in new forms of memory storage and data transfer, such as spintronics and valleytronics, that would revolutionize electronics by making use of materials in new ways to make smaller and more efficient devices.

    The latest result marks the first comprehensive study at the Lab’s Advanced Light Source (ALS) involving a technique called nanoARPES, which researchers enlisted to probe the 2D samples with X-rays.

    LBL ALS

    The X-rays knocked out electrons in the sample, allowing researchers to measure their direction and energy. This revealed nanoscale defects and how the electrons interact with each other.

    The nanoARPES capability is housed in an X-ray beamline, launched in 2016, known as MAESTRO (Microscopic and Electronic Structure Observatory). It is one of dozens of specialized beamlines at the ALS, which produces light in different forms – from infrared to X-rays – for a variety of simultaneous experiments.

    “It’s a very big advance to get this electronic structure on small length scales,” said Eli Rotenberg, a senior staff scientist at the ALS who was a driving force in developing MAESTRO and served as one of the study’s leaders. “That matters for real devices.”

    The team also enlisted a technique known as XPS (X-ray photoelectron spectroscopy) to study the chemical makeup of a sample at very small scales; a form of AFM (atomic force microscopy) to view structural details approaching the atomic scale; and a combined form of optical spectroscopy (Raman/photoluminescence spectroscopy) to study how light interacts with the electrons at microscope scales.

    The various techniques were applied at the Molecular Foundry, where the material was synthesized, and at the ALS.

    LBNL Molecular Foundry

    The sample used in the study contained microscopic, roughly triangular flakes, each measuring about 1 to 5 microns (millionths of a meter) across. They were grown atop titanium dioxide crystals using a conventional layering process known as chemical vapor deposition, and the defects were largely concentrated around the edges of the flakes, a signature of the growth process. Most of the experiments focused on a single flake of tungsten disulfide.

    2
    This image shows an illustration of the atomic structure of a 2D material called tungsten disulfide. Tungsten atoms are shown in blue and sulfur atoms are shown in yellow. The background image, taken by an electron microscope at Berkeley Lab’s Molecular Foundry, shows groupings of flakes of the material (dark gray) grown by a process called chemical vapor deposition on a titanium dioxide layer (light gray). (Credit: Katherine Cochrane/Berkeley Lab)

    Adam Schwartzberg, a staff scientist at the Molecular Foundry who served as a co-lead in the study, said, “It took a combination of multiple types of techniques to pin down what’s really going on.”

    He added, “Now that we know what defects we have and what effect they have on the properties of the material, we can use this information to reduce or eliminate defects – or if you want the defect, it gives us a way of knowing where the defects are,” and provides fresh insight about how to propagate and amplify the defects in the sample-production process.

    While the concentration of edge defects in the WS2 flakes was generally known before the latest study, Schwartzberg said that their effects on materials performance hadn’t previously been studied in such a comprehensive and detailed way.

    Researchers learned that a 10 percent deficiency in sulfur atoms was associated with the defective edge regions of the samples compared to other regions, and they identified a slighter, 3 percent sulfur deficiency toward the center of the flakes. Researchers also noted a change in the electronic structure and higher abundance of freely moving electrical charge-carriers associated with the high-defect edge areas.

    4
    This sequence of images shows a variety of energy intensities (white and yellow) at the edges of a 2D material known as tungsten disulfide, as measured via different techniques: photoluminescense intensity (far left); contact potential difference map (second from left); exciton emission intensity (third from left) – excitons are pairs consistent of an electrons and their quasiparticle counterpart, called a hole; trion emission intensity (far right) – trions are gropus of three charged quasiparticles consistening of either two electrons and a hole or two holes and an electron). (Credit: Christoph Kastl/Berkeley Lab)

    For this study, the defects were due to the sample-growth process. Future nanoARPES studies will focus on samples with defects that are induced through chemical processing or other treatments. Researchers hope to control the amount and kinds of atoms that are affected, and the locations where these defects are concentrated in the flakes.

    Such tiny tweaks could be important for processes like catalysis, which is used to enhance and accelerate many important industrial chemical production processes, and to explore quantum processes that rely on the production of individual particles that serve as information carriers in electronics.

    Because research of WS2 and related 2D materials is still in its infancy, there are many unknowns about the roles specific types of defects play in these materials, and Rotenberg noted that there is a world of possibilities for so-called “defect engineering” in these materials.

    In addition, MAESTRO’s nanoARPES has the ability to study the electronic structures of stacks of different types of 2D material layers. This can help researchers understand how their properties depend on their physical arrangement, and to explore working devices that incorporate 2D materials.

    “The unprecedented small scale of the measurements – currently approaching 50 nanometers – makes nanoARPES a great discovery tool that will be particularly useful to understand new materials as they are invented,” Rotenberg said.

    MAESTRO is one of the priority beamlines to be upgraded as part of the Lab’s ALS Upgrade (ALS-U) project, a major undertaking that will produce even brighter, more focused beams of light for experiments. “The ALS-U project will further improve the performance of the nanoARPES technique,” Rotenberg said, “making its measurements 10 to 30 times more efficient and significantly improving our ability to reach even shorter length scales.”

    NanoARPES could play an important role in the development of new solar technologies, because it allows researchers to see how nanoscale variations in chemical makeup, number of defects, and other structural features affect the electrons that ultimately govern their performance. These same issues are important for many other complex materials, such as superconductors, magnets, and thermoelectrics – which convert temperature to current and vice versa – so nanoARPES will also be very useful for these as well.

    The Molecular Foundry and ALS are both DOE Office of Science User Facilities.

    Researchers from the Berkeley Lab Chemical Sciences Division, Aarhus University in Denmark, and Montana State University also participated in this study. The work was supported by the U.S. Department of Energy’s Office of Basic Energy Sciences, the DOE Early Career Grant program, Berkeley Lab’s Laboratory Directed Research and Development program, the Villum Foundation, and the German Academic Exchange Service.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Bringing Science Solutions to the World

    In the world of science, Lawrence Berkeley National Laboratory (Berkeley Lab) is synonymous with “excellence.” Thirteen Nobel prizes are associated with Berkeley Lab. Seventy Lab scientists are members of the National Academy of Sciences (NAS), one of the highest honors for a scientist in the United States. Thirteen of our scientists have won the National Medal of Science, our nation’s highest award for lifetime achievement in fields of scientific research. Eighteen of our engineers have been elected to the National Academy of Engineering, and three of our scientists have been elected into the Institute of Medicine. In addition, Berkeley Lab has trained thousands of university science and engineering students who are advancing technological innovations across the nation and around the world.

    Berkeley Lab is a member of the national laboratory system supported by the U.S. Department of Energy through its Office of Science. It is managed by the University of California (UC) and is charged with conducting unclassified research across a wide range of scientific disciplines. Located on a 202-acre site in the hills above the UC Berkeley campus that offers spectacular views of the San Francisco Bay, Berkeley Lab employs approximately 3,232 scientists, engineers and support staff. The Lab’s total costs for FY 2014 were $785 million. A recent study estimates the Laboratory’s overall economic impact through direct, indirect and induced spending on the nine counties that make up the San Francisco Bay Area to be nearly $700 million annually. The Lab was also responsible for creating 5,600 jobs locally and 12,000 nationally. The overall economic impact on the national economy is estimated at $1.6 billion a year. Technologies developed at Berkeley Lab have generated billions of dollars in revenues, and thousands of jobs. Savings as a result of Berkeley Lab developments in lighting and windows, and other energy-efficient technologies, have also been in the billions of dollars.

    Berkeley Lab was founded in 1931 by Ernest Orlando Lawrence, a UC Berkeley physicist who won the 1939 Nobel Prize in physics for his invention of the cyclotron, a circular particle accelerator that opened the door to high-energy physics. It was Lawrence’s belief that scientific research is best done through teams of individuals with different fields of expertise, working together. His teamwork concept is a Berkeley Lab legacy that continues today.

    A U.S. Department of Energy National Laboratory Operated by the University of California.

    University of California Seal

    DOE Seal

     
  • richardmitnick 5:32 pm on March 7, 2019 Permalink | Reply
    Tags: a field that could extend the limits of Moore’s law by miniaturizing electronic components, A new study led by Berkeley Lab reveals how aligned layers of atomically thin semiconductors can yield an exotic new quantum material, A team of researchers led by the Department of Energy’s Lawrence Berkeley National Laboratory has developed a method that could turn ordinary semiconducting materials into quantum machines, Aiming Yan and Alex Zettl used a transmission electron microscope (TEM) at Berkeley Lab’s Molecular Foundry to take atomic-resolution images, Also contributing to the study were researchers from Arizona State University and the National Institute for Materials Science in Japan, Also valleytronics, and superconductivity which would allow electrons to flow in devices with virtually no resistance, , “This is an amazing discovery because we didn’t think of these semiconducting materials as strongly interacting” said Feng Wang, LBNL, , The researchers next plan to measure how this new quantum system could be applied to optoelectronics, The TEM images confirmed what they had suspected all along: the materials had indeed formed a moiré superlattice, Two-dimensional (2D) materials which are just one atom thick are like nanosized building blocks that can be stacked arbitrarily to form tiny devices, When the lattices of two 2D materials are similar and well-aligned a repeating pattern called a moiré superlattice can form   

    From Lawrence Berkeley National Lab: “When Semiconductors Stick Together, Materials Go Quantum” 

    Berkeley Logo

    From Lawrence Berkeley National Lab

    March 7, 2019
    Theresa Duque
    tnduque@lbl.gov
    (510) 495-2418

    A new study led by Berkeley Lab reveals how aligned layers of atomically thin semiconductors can yield an exotic new quantum material.

    1
    A method developed by a Berkeley Lab-led research team may one day turn ordinary semiconducting materials into quantum electronic devices. (Credit: iStock.com/NiPlot)

    A team of researchers led by the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) has developed a simple method that could turn ordinary semiconducting materials into quantum machines – superthin devices marked by extraordinary electronic behavior. Such an advancement could help to revolutionize a number of industries aiming for energy-efficient electronic systems – and provide a platform for exotic new physics.

    The study describing the method, which stacks together 2D layers of tungsten disulfide and tungsten diselenide to create an intricately patterned material, or superlattice, was published online recently in the journal Nature.

    “This is an amazing discovery because we didn’t think of these semiconducting materials as strongly interacting,” said Feng Wang, a condensed matter physicist with Berkeley Lab’s Materials Sciences Division and professor of physics at UC Berkeley. “Now this work has brought these seemingly ordinary semiconductors into the quantum materials space.”

    2
    The twist angle formed between atomically thin layers of tungsten disulfide and tungsten diselenide acts as a “tuning knob,” transforming these semiconductors into an exotic quantum material. (Credit: Berkeley Lab) (Credit: Berkeley Lab)

    Two-dimensional (2D) materials, which are just one atom thick, are like nanosized building blocks that can be stacked arbitrarily to form tiny devices. When the lattices of two 2D materials are similar and well-aligned, a repeating pattern called a moiré superlattice can form.

    For the past decade, researchers have been studying ways to combine different 2D materials, often starting with graphene – a material known for its ability to efficiently conduct heat and electricity. Out of this body of work, other researchers had discovered that moiré superlattices formed with graphene exhibit exotic physics such as superconductivity when the layers are aligned at just the right angle.

    The new study, led by Wang, used 2D samples of semiconducting materials – tungsten disulfide and tungsten diselenide – to show that the twist angle between layers provides a “tuning knob” to turn a 2D semiconducting system into an exotic quantum material with highly interacting electrons.

    Entering a new realm of physics

    Co-lead authors Chenhao Jin, a postdoctoral scholar, and Emma Regan, a graduate student researcher, both of whom work under Wang in the Ultrafast Nano-Optics Group at UC Berkeley, fabricated the tungsten disulfide and tungsten diselenide samples using a polymer-based technique to pick up and transfer flakes of the materials, each measuring just tens of microns in diameter, into a stack.

    They had fabricated similar samples of the materials for a previous study [Science], but with the two layers stacked at no particular angle. When they measured the optical absorption of a new tungsten disulfide and tungsten diselenide sample for the current study, they were taken completely by surprise.

    The absorption of visible light in a tungsten disulfide/tungsten diselenide device is largest when the light has the same energy as the system’s exciton, a quasiparticle that consists of an electron bound to a hole that is common in 2D semiconductors. (In physics, a hole is a currently vacant state that an electron could occupy.)

    3
    The large potential energy of three distinct exciton states in a 2D tungsten disulfide/tungsten diselenide device could introduce exotic quantum phenomena into semiconducting materials. (Credit: Berkeley Lab)

    For light in the energy range that the researchers were considering, they expected to see one peak in the signal that corresponded to the energy of an exciton.

    Instead, they found that the original peak that they expected to see had split into three different peaks representing three distinct exciton states.

    What could have increased the number of exciton states in the tungsten disulfide/tungsten diselenide device from one to three? Was it the addition of a moiré superlattice?

    To find out, their collaborators Aiming Yan and Alex Zettl used a transmission electron microscope (TEM) at Berkeley Lab’s Molecular Foundry, a nanoscale science research facility, to take atomic-resolution images of the tungsten disulfide/tungsten diselenide device to check how the materials’ lattices were aligned.

    The TEM images confirmed what they had suspected all along: the materials had indeed formed a moiré superlattice. “We saw beautiful, repeating patterns over the entire sample,” said Regan. “After comparing this experimental observation with a theoretical model, we found that the moiré pattern introduces a large potential energy periodically over the device and could therefore introduce exotic quantum phenomena.”

    The researchers next plan to measure how this new quantum system could be applied to optoelectronics, which relates to the use of light in electronics; valleytronics, a field that could extend the limits of Moore’s law by miniaturizing electronic components; and superconductivity, which would allow electrons to flow in devices with virtually no resistance.

    Also contributing to the study were researchers from Arizona State University and the National Institute for Materials Science in Japan.

    The work was supported by the DOE Office of Science. Additional funding was provided by the National Science Foundation, the Department of Defense, and the Elemental Strategy Initiative conducted by MEXT, Japan, and JSPS KAKENHI. The Molecular Foundry is a DOE Office of Science user facility.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Bringing Science Solutions to the World

    In the world of science, Lawrence Berkeley National Laboratory (Berkeley Lab) is synonymous with “excellence.” Thirteen Nobel prizes are associated with Berkeley Lab. Seventy Lab scientists are members of the National Academy of Sciences (NAS), one of the highest honors for a scientist in the United States. Thirteen of our scientists have won the National Medal of Science, our nation’s highest award for lifetime achievement in fields of scientific research. Eighteen of our engineers have been elected to the National Academy of Engineering, and three of our scientists have been elected into the Institute of Medicine. In addition, Berkeley Lab has trained thousands of university science and engineering students who are advancing technological innovations across the nation and around the world.

    Berkeley Lab is a member of the national laboratory system supported by the U.S. Department of Energy through its Office of Science. It is managed by the University of California (UC) and is charged with conducting unclassified research across a wide range of scientific disciplines. Located on a 202-acre site in the hills above the UC Berkeley campus that offers spectacular views of the San Francisco Bay, Berkeley Lab employs approximately 3,232 scientists, engineers and support staff. The Lab’s total costs for FY 2014 were $785 million. A recent study estimates the Laboratory’s overall economic impact through direct, indirect and induced spending on the nine counties that make up the San Francisco Bay Area to be nearly $700 million annually. The Lab was also responsible for creating 5,600 jobs locally and 12,000 nationally. The overall economic impact on the national economy is estimated at $1.6 billion a year. Technologies developed at Berkeley Lab have generated billions of dollars in revenues, and thousands of jobs. Savings as a result of Berkeley Lab developments in lighting and windows, and other energy-efficient technologies, have also been in the billions of dollars.

    Berkeley Lab was founded in 1931 by Ernest Orlando Lawrence, a UC Berkeley physicist who won the 1939 Nobel Prize in physics for his invention of the cyclotron, a circular particle accelerator that opened the door to high-energy physics. It was Lawrence’s belief that scientific research is best done through teams of individuals with different fields of expertise, working together. His teamwork concept is a Berkeley Lab legacy that continues today.

    A U.S. Department of Energy National Laboratory Operated by the University of California.

    University of California Seal

    DOE Seal

     
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