The Stanford Synchrotron Radiation Lightsource , a division of SLAC National Accelerator Laboratory, is operated by Stanford University for the Department of Energy. SSRL is a National User Facility which provides synchrotron radiation, a name given to electromagnetic radiation in the x-ray, ultraviolet, visible and infrared realms produced by electrons circulating in a storage ring at nearly the speed of light. The extremely bright light that is produced can be used to investigate various forms of matter ranging from objects of atomic and molecular size to man-made materials with unusual properties. The obtained information and knowledge is of great value to society, with impact in areas such as the environment, future technologies, health, and education.The SSRL provides experimental facilities to some 2,000 academic and industrial scientists working in such varied fields as drug design, environmental cleanup, electronics, and x-ray imaging. It is located in southern San Mateo County, just outside the city of Menlo Park. Wikipedia.
News Article | May 12, 2017
VAC and LBNL's new jointly-developed magnet design assembly, containing VAC's new VACODYM 956 DTP material and its VACOFLUX 50 parts, enables extremely narrow required magnetic and mechanical tolerances. These tolerances define the quality of the undulator systems, and ultimately the FEL. This new product has enabled VAC to replace a competitor that supplied the magnet design assembly for SLAC's first LCLS project. Additionally, the partnership of VAC and Lawrence Berkeley represents an important milestone for VAC Americas as it establishes a deepened presence within the North American market and provides a technology solution that can be relied upon in critical applications. "We are very pleased that LCLS-II in the USA is now using our magnets and magnet systems. In addition to several other major FEL projects, including the European XFEL in Germany, the Swiss FEL in Switzerland, and the PAL FEL in Korea, this is the fourth large-scale project that uses our materials. These research facilities nearly cover the complete Free Electron Laser energy spectrum" per Dr. Ralf Koch, head of Research & Development at VAC. Dr. Koch added that "VAC's broader range of VACODYM and VACOFLUX solutions can be used in additional applications, including automotive sensors, MRI systems, beam guiding systems and electronic measuring instruments, among others." Matthaeus Leitner, a lead engineer at LBNL, also commented, "We chose VAC as a partner since VAC had the technical resources to develop integrated and fully assembled undulator modules. During the whole project life, maintaining a close communication between VAC and LBNL was essential, since the magnet module design had to be refined from early prototypes to full production. Throughout the project, VAC's technical team has been a tremendously supportive and knowledgeable partner, with experts in the field supporting LBNL in Germany as well as directly in the U.S." Beyond using VAC-LBNL undulators at its own facility, LBNL is starting to provide these undulators to other institutions that research FELs. To these institutions, LBNL will be able to highlight its relationship with SLAC that is financed, inter alia, by the U.S. Department of Energy, and that now uses the VAC-LBNL undulators in its LCLS-II particle accelerator project, which is planned to be activated in 2019. VAC, a VECTRA company, develops, manufactures and distributes differentiated, highly-specialized magnetic alloys, materials and components with exceptional magnetic and/or physical properties for a wide array of end markets and applications, including automotive systems, electrical installation technology, energy conversion and distribution, industrial automation/robotics, retail and renewable energy. For more information, visit VAC's website at http://www.vacuumschmelze.com/ VECTRA is a technology-driven diversified industrial company serving attractive global markets, including automotive systems, electronic devices, aerospace and defense, industrial and medical. Its business platforms use technology to address customers' complex applications and demanding requirements. For more information, visit VECTRA's website at www.vectraco.com To view the original version on PR Newswire, visit:http://www.prnewswire.com/news-releases/vacuumschmelze-delivers-undulator-magnet-assemblies-to-lawrence-berkeley-national-laboratories-for-development-of-advanced-x-ray-laser-300456972.html
News Article | May 11, 2017
On April 12, one of the spacecraft's instruments – the Large Area Telescope (LAT), which was conceived of and assembled at the Department of Energy's SLAC National Accelerator Laboratory – detected its billionth extraterrestrial gamma ray. Since gamma rays are often produced in violent processes, their observation sheds light on extreme cosmic environments, such as powerful star explosions, high-speed particle jets spewed out by supermassive black holes, and ultradense neutron stars spinning unimaginably fast. Gamma rays could also be telltale signs of dark matter particles – hypothetical components of invisible dark matter, which accounts for 85 percent of all matter in the universe. "Since Fermi's launch in 2008, the LAT has made a number of important discoveries of gamma-ray emissions from exotic sources in our galaxy and beyond," says Robert Cameron, head of the LAT Instrument Science Operations Center (ISOC) at SLAC. The LAT has already collected hundreds of times more gamma rays than the previous-generation EGRET instrument on NASA's Compton Gamma-ray Observatory – an advance that has tremendously deepened insights into the production of this energetic radiation. Among the LAT discoveries are more than 200 pulsars – rapidly rotating, highly magnetized cores of collapsed stars that were up to 30 times more massive than the sun. Before Fermi's launch, only seven of these objects were known to emit gamma rays. As pulsars spin around their axis, they emit "beams" of gamma rays like cosmic lighthouses. Many pulsars rotate several hundred times per second – that's tens of millions times faster than Earth's rotation. "Understanding pulsars tells us about the evolution of stars because they are one possible end point in a star's life," Cameron says. "The LAT data have led us to totally revise our understanding of how pulsars emit gamma rays." The LAT has also shown for the first time that novae – thermonuclear explosions on the surface of stars that have accumulated material from neighboring stars – can emit gamma rays. These data provide new details about the physics of burning stars, which is a crucial process for the synthesis of chemical elements in the universe. Even more exotic gamma-ray sources detected by the LAT are microquasars. These objects are star-sized analogs of active galactic nuclei, with gas spinning around a black hole at the center. As the black hole devours matter from its surroundings, it ejects jets of charged particles traveling almost as fast as light into space, generating beams of gamma rays in the process. At a galactic scale, such an ejection mechanism could have produced what is known as the Fermi bubbles – two giant areas above and below the center of the disk of our Milky Way galaxy that shine in gamma rays. Discovered by the LAT in 2010, these bubbles suggest that the supermassive black hole at the center of our galaxy once was more active than it is today. Researchers also use the LAT to search for signs of dark matter particles in the central regions of the Milky Way and other galaxies. Theories predict that the hypothetical particles would produce gamma rays when they decay or collide and destroy each other. "With the sensitivity we have achieved with the LAT, we should in principle be able to see such dark matter signatures," says SLAC's Seth Digel, who leads the Fermi group at the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), a joint institute of Stanford University and SLAC. "But we haven't found any conclusive signals yet, and so far the LAT data can also be explained with other astrophysical sources." Finally, the LAT has explored gamma ray sources closer to home, including gamma rays produced by thunderstorms in Earth's atmosphere, by solar flares and even by charged particles hitting the surface of the moon. From its location on Fermi at an altitude of 330 miles, the LAT sees 20 percent of the sky at any given time. Every two orbits – each takes about 95 minutes – the instrument collects the data necessary for a gamma-ray map of the entire sky. But identifying the right signals for the map is a little bit like finding needles in a haystack: For every gamma-ray photon, the LAT sees many more high-energy charged particles, called cosmic rays. Most of these background signals are rejected right away by hardware triggers and software filters in the LAT on Fermi, which reduces the rate of signals from 10,000 to 400 per second. The remaining data are compressed, transmitted back to Earth and sent to NASA's Goddard Space Flight Center in Greenbelt, Maryland, where they get separated into three different datasets for the LAT, the GBM (Fermi's second scientific instrument, which monitors short-lived gamma-ray bursts) and spacecraft data. The LAT data are transferred to the LAT ISOC at SLAC, where 1,000 computer cores automatically analyze the data stream and filter out even more background signals. 70 percent of all detected gamma rays are from Earth's atmosphere, leaving only two to three extraterrestrial gamma-ray signals per second out of the 10,000 initial detector events. These data are then sent back to NASA Goddard, where they are made publicly available for further analysis. "The ISOC receives about 15 deliveries of LAT data throughout the day for a total of 16 gigabytes or three DVDs worth of data every day," Cameron says. "For each delivery, the entire process – from the time the data leave Fermi to the time the gamma rays get deposited in the public archive – takes about four hours." Next year, the Fermi mission will reach its 10-year operations goal. What happens after that will largely depend on funding. "With no successor mission planned, the LAT is in many ways irreplaceable, particularly for studies of low-energy gamma rays," Digel says. "The telescope is still going strong after all these years, and there is a lot of science left to be done." An important new role for the LAT is to search for gamma-ray sources associated with gravitational wave events. These ripples in space-time occur, for example, when two black holes merge into a single one, as recently observed by the LIGO detector. This opens up the completely new field of gravitational wave astrophysics. The LAT ISOC is a department in KIPAC and the Particle Astrophysics and Cosmology Division of SLAC. KIPAC researchers contribute to the international Fermi LAT Collaboration, whose research is funded by NASA and the DOE Office of Science, as well as agencies and institutes in France, Italy, Japan and Sweden. Explore further: Origin of Milky Way's hypothetical dark matter signal may not be so dark
News Article | June 8, 2017
When the X-rays blast electrons out of one atom, stripping it from the inside out, it steals more from its neighbors -- a new insight that could help advance high-resolution imaging of whole viruses, bacteria and complex materials. With the most highly focused power of the world's most powerful X-ray laser, scientists from a number of institutions around the world- - including the U.S. Department of Energy's (DOE) Argonne National Laboratory -- have conducted a new experiment that takes apart molecules electron by electron. "The key to this experiment was being able to focus hard X-rays to a very tiny spot." The results of this experiment, carried out at DOE's SLAC National Accelerator Laboratory and published today in Nature, showed a surprising effect at the atomic scale. The researchers saw that a single laser pulse stripped all but a few electrons out of the molecule's biggest atom, leaving a void that started pulling in electrons from the rest of the molecule, like a black hole gobbling a spiraling disk of matter. Within 30 femtoseconds - millionths of a billionth of a second - the molecule lost more than 50 electrons, far more than scientists anticipated based on earlier experiments using less intense beams or isolated atoms. Then it blew up. "The key to this experiment was being able to focus hard X-rays to a very tiny spot," said Argonne scientist Linda Young, an author of the study. "By concentrating the X-rays on a single atom in a molecule, we can see and even predict -- on a very fast time scale -- the electron movement between different atoms in the molecule and track unusual behaviors." "This paper shows that we can understand and model the radiation damage in small molecules, so now we can predict what damage we will get in other systems," added Daniel Rolles of Kansas State University, another author of the study. The experiment gives scientists fundamental insights they need to better plan and interpret experiments using intense and energetic X-ray pulses, like those created by the free-electron X-ray laser at the Linac Coherent Light Source at SLAC. Experiments that require these ultrahigh intensities include attempts to image individual biological objects, such as viruses and bacteria, at high resolution. They are also used to study the behavior of matter under extreme conditions, and to better understand charge dynamics in complex molecules. The work represents a follow-on to an earlier experiment carried out by Young and other collaborators in 2010. The current experiment involves a much tighter focus of the X-ray energy, producing roughly 100 times higher intensity than previously achieved. The current study also involved a significant theoretical component. "Because this experiment involves such high intensities and so many electrons, the theory is quite elaborate - you must calculate many different trajectories on the fly for multiple electronic configurations and molecular geometries. Because everything is happening on the same ultrafast time scale, it's quite challenging," Young said. The experiment, led by Rolles and Artem Rudenko of Kansas State, took place at LCLS's Coherent X-ray Imaging (CXI) instrument. CXI delivers X-rays with the highest possible intensities achievable at LCLS and records data from samples in the instant before the laser pulse destroys them. How intense are those X-ray pulses? "They are about a hundred times more intense than what you would get if you focused all the sunlight that hits the Earth's surface onto a thumbnail," said LCLS staff scientist and co-author Sebastien Boutet. For this study, researchers used special mirrors to focus the X-ray beam into a spot just over 100 nanometers in diameter - about a hundredth the size of the one used in most CXI experiments, and a thousand times smaller than the width of a human hair. They looked at three types of samples: individual xenon atoms, which have 54 electrons each, and two types of molecules that each contain a single iodine atom, which has 53 electrons. Heavy atoms around this size are important in biochemical reactions, and researchers sometimes add them to biological samples to enhance contrast for imaging and crystallography applications. But until now, no one had investigated how the ultra-intense CXI beam affects molecules with atoms this heavy. The team tuned the energy of the CXI pulses so they would selectively strip the innermost electrons from the xenon or iodine atoms, creating "hollow atoms." Based on earlier studies with less energetic X-rays, they thought cascades of electrons from the outer parts of the atom would drop down to fill the vacancies, only to be kicked out themselves by subsequent X-rays. That would leave just a few of the most tightly bound electrons. And, in fact, that's what happened in both the freestanding xenon atoms and the iodine atoms in the molecules. But in the molecules, the process didn't stop there. The iodine atom, which had a strong positive charge after losing most of its electrons, continued to suck in electrons from neighboring carbon and hydrogen atoms, and those electrons were also ejected, one by one. Rather than losing 47 electrons, as would be the case for an isolated iodine atom, the iodine in the smaller molecule lost 54, including the ones it grabbed from its neighbors - a level of damage and disruption that's not only higher than would normally be expected, but significantly different in nature. "We think the effect was even more important in the larger molecule than in the smaller one, but we don't know how to quantify it yet," Rudenko said. "We estimate that more than 60 electrons were kicked out, but we don't actually know where it stopped because we could not detect all the fragments that flew off as the molecule fell apart to see how many electrons were missing. This is one of the open questions we need to study." For the data analyzed to date, the theoretical model provided excellent agreement with the observed behavior, providing confidence that more complex systems can now be studied, said LCLS director Mike Dunne. "This has important benefits for scientists wishing to achieve the highest-resolution images of biological molecules to inform the development of better pharmaceuticals, for example," he said. "These experiments will also guide the development of a next-generation instrument for the LCLS-II upgrade project, which will provide a major leap in capability due to the increase in repetition rate from 120 pulses per second to 1 million." The theory work for the study was led by Robin Santra of the Center for Free-Electron Laser Science at DESY and the University of Hamburg in Germany. Other research institutions contributing to the study were Tohoku University in Japan; Max Planck Institute for Nuclear Physics, Max Planck Institute for Medical Research, Hamburg Center for Ultrafast Imaging and the National Metrology Institute (PTB) in Germany; the University of Science and Technology in Beijing; Aarhus University in Denmark; Sorbonne University in France; the DOE's Argonne National Laboratory and Brookhaven National Laboratory; the University of Chicago; Kansas State University; and Northwestern University. Funding for the research came from the DOE Office of Science [Basic Energy Sciences, Chemical Sciences, Geosciences and Biosciences Division] and from the German Research Foundation (DFG). SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the U.S. Department of Energy Office of Science. To learn more, please visit http://www. . SLAC National Accelerator Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov. Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation's first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America's scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy's Office of Science. The U.S. Department of Energy's Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit the Office of Science website.
Brongersma M.L.,Stanford University |
Cui Y.,Stanford University |
Cui Y.,SLAC |
Fan S.,Stanford University
Nature Materials | Year: 2014
High-performance photovoltaic cells use semiconductors to convert sunlight into clean electrical power, and transparent dielectrics or conductive oxides as antireflection coatings. A common feature of these materials is their high refractive index. Whereas high-index materials in a planar form tend to produce a strong, undesired reflection of sunlight, high-index nanostructures afford new ways to manipulate light at a subwavelength scale. For example, nanoscale wires, particles and voids support strong optical resonances that can enhance and effectively control light absorption and scattering processes. As such, they provide ideal building blocks for novel, broadband antireflection coatings, light-trapping layers and super-absorbing films. This Review discusses some of the recent developments in the design and implementation of such photonic elements in thin-film photovoltaic cells. © 2014 Macmillan Publishers Limited.
Analytical Chemistry | Year: 2013
Atomic resolution structures of large biomacromolecular complexes can now be recorded at room temperature from crystals with submicrometer dimensions using intense femtosecond pulses delivered by the worlds largest and most powerful X-ray machine, a laser called the Linac Coherent Light Source. Abundant opportunities exist for the bioanalytical sciences to help extend this revolutionary advance in structural biology to the ultimate goal of recording molecular-movies of noncrystalline biomacromolecules. This Feature will introduce the concept of serial femtosecond crystallography to the nonexpert, briefly review progress to date, and highlight some potential contributions from the analytical sciences. © 2013 American Chemical Society.
Luntz A.C.,SLAC |
McCloskey B.D.,University of California at Berkeley |
McCloskey B.D.,Lawrence Berkeley National Laboratory
Chemical Reviews | Year: 2014
The major issue confronting complete electrification of road transport is simply a battery problem. While both metrics are undoubtedly important, which of the two is the most important for EV applications is somewhat debated, even among the different EV manufacturers. Traditional car companies emphasize more the importance of energy density, while Tesla emphasizes more the specific energy since they tend to design a car around the battery pack. The history of rechargeable non-aqueous Li-air batteries at this stage is so short that the field must be considered a work in progress. In fact, even the basic mechanisms and rationale for many of the fundamental properties of Li-air are still in dispute among many of the researchers in the field.
Nature Materials | Year: 2012
Stefan C. B. Mannsfeld states that development in organic electronics depends on the understanding of the structure-property relationships of organic materials. Resonant scattering of polarized soft X-rays (P-SoXS) by aromatic carbon bonds has been used to probe molecular orientation in thin organic semiconductor films down to length scales of 20 nm. The basic principle of the P-SoXS technique involves a polarized soft X-ray beam passing through a thin sample and the scattering signal and recorded by an X-ray sensitive detector. Soft X-rays are distinguished from hard X-rays by their lower photon energies, which fall into the same energy range as the fundamental electronic transitions of many lighter atoms, including carbon. The novelty of P-SoXS lies in the use of scattering with polarized soft X-rays whose energy is tuned to a fundamental carbon transition in aromatic carbon ring systems.
Journal of Synchrotron Radiation | Year: 2014
It has been known for decades that the emittance of multi-GeV storage rings can be reduced to very small values using multi-bend achromat (MBA) lattices. However, a practical design of a ring having emittance approaching the diffraction limit for multi-keV photons, i.e. a diffraction-limited storage ring (DLSR), with a circumference of order 1km or less was not possible before the development of small-aperture vacuum systems and other accelerator technology, together with an evolution in the understanding and accurate simulation of non-linear beam dynamics, had taken place. The 3-GeV MAXIV project in Sweden has initiated a new era of MBA storage ring light source design, i.e. a fourth generation, with the Sirius project in Brazil now following suit, each having an order of magnitude smaller horizontal emittance than third-generation machines. The ESRF, APS and SPring-8 are all exploring 6-GeV MBA lattice conversions in the imminent future while China is considering a similar-energy green-field machine. Other lower-energy facilities, including the ALS, SLS, Soleil, Diamond and others, are studying the possibility of such conversions. Future larger-circumference rings, possibly housed in >2-km tunnels made available by decommissioned high-energy physics accelerators, could have sub-10-pm-rad emittances, providing very high coherence for >10-keV X-rays. A review of fourth-generation ring design concepts and plans in the world is presented. © 2014 International Union of Crystallography.
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014
The production of new gauge bosons is a standard benchmark for the exploration of the physics capabilities of future colliders. The s=100TeV future hadron collider will make a major step in our ability to search for and explore the properties of such new states. In this paper, employing traditional models to make contact with the past and more recent literature, we not only establish in detail the discovery and exclusion reaches for both the Z′ and W′ within these models, but, more importantly, we also examine the capability of the future hadron collider to extract information relevant for the determination of the couplings of the Z′ to the fermions of the Standard Model as well as the helicity of the corresponding W′ couplings. This is a necessary first step in determining the nature of the underlying theory, which gave rise to these states. © 2014 American Physical Society.
Agency: Department of Energy | Branch: | Program: STTR | Phase: Phase I | Award Amount: 150.00K | Year: 2016
There is a continuing need for high power circulators to protect the next generation of high power RF sources from waveguide reflections that can destroy the device. Currently, the power level of circulators is limited by the materials, specifically ferrites that provide the required non-reciprocal operation. New approaches are required that use materials capable of very high power operation. Statement of how this problem or situation is being addressed Calabazas Creek Research Inc. and SLAC National Accelerator Laboratory propose to explore a new approach that avoids ferrites and other materials unable to support high power operation. The new approach uses coupled cavities and RF modulation to provide the required performance. Commercial Applications and Other Benefits High power circulators are required whenever high power RF sources are driving loads where reflected power may occur. This includes RF sources for high energy accelerators and colliders. Circulators are also used in some high power radar applications and are a key component of a magnetron-based power source being developed for accelerators. Key Words. Circulator, ferrites, piezoelectric, RF source, accelerator Summary for Members of Congress The proposed program will develop a device to protect high power RF sources from destructive reflections in accelerator and collider applications. This will allow an increase of source power, reducing cost for these systems.