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  • richardmitnick 8:05 am on April 27, 2017 Permalink | Reply
    Tags: , , Paul Fuoss, SLAC,   

    From SLAC: “Where Scientist Meets Machine: A Fresh Approach to Experimental Design at SLAC X-Ray Laser” 


    SLAC Lab

    April 26, 2017
    Glennda Chui

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    Paul Fuoss, the new head of experimental design at SLAC’s Linac Coherent Light Source X-ray laser. (Dawn Harmer/SLAC National Accelerator Laboratory)

    Paul Fuoss’s Mission is to Make Experiments at LCLS and Other Light Sources More Productive and User-Friendly

    Big leaps in technology require big leaps in design ­– entirely new approaches that can take full advantage of everything the technology has to offer.

    That’s the thinking behind a new initiative at the Department of Energy’s SLAC National Accelerator Laboratory. To make sure experimenters can get the most out of a major X-ray laser upgrade that will produce beams that are 10,000 times brighter and pulses up to a million times per second, the lab has created a new position – head of experimental design at the Linac Coherent Light Source – and hired a world-renowned X-ray scientist to fill it.

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    The first 21 of 33 undulators in place in the LCLS Undulator Hall. (Photo by Mike Zurawel.)

    Paul Fuoss (pronounced “foos”) will look at LCLS and the LCLS-II upgrade from a fresh perspective and work with scientists and engineers across the lab to design instruments, user-friendly control systems and experimental flows that take full advantage of this technological leap.

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    Although the upgrade won’t be finished until the early 2020s, there’s really no time to lose, said LCLS Director Mike Dunne.

    “We’re on the verge of a transformation of our science capabilities that is simply unattainable today. When you take these big leaps you have to fundamentally rethink how you approach the science and the design of experiments,” Dunne said.

    “You can’t just do it the way you did before but a bit better. You have to approach it from a completely new thought process: What is the scientific knowledge you’re trying to get out, and what is the scientific data that might illuminate that new understanding, and how does that translate back into how you obtain that data, and how does that influence how you design the facility?”

    Taming Complexity to Make Science More Productive

    For Fuoss, the broader goal is to increase productivity and improve the experiences of scientists at X-ray light sources everywhere.

    “Experiments have gotten a lot more complex over the past 20 years, not just at LCLS but at synchrotron light sources, too,” he said. “We’ve gone from controlling experiments with a single computer and detecting a single pixel of data at a time to using multiple computers and detecting more like a million pixels at once. Our ability to integrate different tools and computers and visualize the data has often not kept up with the technology. And at LCLS, that complexity is going to increase dramatically in a few years when the LCLS-II upgrade becomes operational.”

    One way to make working with LCLS more streamlined and intuitive is to incorporate user-friendly features into the instruments that come on board as part of LCLS-II.

    “A lot of that will be working with the scientists and engineers who are designing those instruments to get the building blocks for user compatibility in there,” Fuoss said. “It’s not part of the core training of scientists and engineers, so we expect we will need to reach out to people who have that expertise and get them to help us.”

    Another way, he said, is to create tools that let scientists visualize their data as it’s being collected, so they can understand what is going on in real time.

    “There are a lot of different pieces that need to be coordinated,” Fuoss said. “All of them are currently being done, but we need to bring a unified focus and make sure there are no unnecessary barriers. Ultimately, you want to integrate this kind of thing into everyone’s day-to-day development activities.”

    X-Rays, Inventions and Human Interfaces

    Fuoss has deep roots at SLAC. Originally from South Dakota, where he grew up on a ranch, he earned a degree in physics at South Dakota School of Mines and Technology and came to Stanford University in 1975 for graduate school. He wound up doing his graduate research at SLAC, using X-rays from what later became the Stanford Synchrotron Radiation Lightsource (SSRL) to investigate materials.

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    SSRL-Stanford Synchrotron Radiation Lightsource – Stanford University

    After earning a PhD, Fuoss went on to do research at Bell Laboratories, AT&T Laboratories and Argonne National Laboratory. He’s been an active user of SSRL and other light sources and has developed a number of new techniques for exploring materials with X-rays, many of which are now standard at light sources around the world; in 2015 he received SLAC’s Farrel W. Lytle Award for this work. Fuoss also played a role in designing LCLS.

    In the mid-1990s, while a researcher at AT&T Laboratories, Fuoss took a six-year detour into the world of human interface design and human factors research – the study of how people interact with technology, from airplane cockpits to your office copier. Back then, he focused on making telecommunications systems and web interfaces more user friendly. This experience can also be applied to LCLS experimental design.

    “Paul has an incredible background,” Dunne said. “He brings that deep understanding of the nature of X-ray science, an understanding of all the instruments and the technical pieces, and then an understanding of what we’re trying to achieve scientifically.”

    Getting the Most out of Beam Time

    Unlike synchrotron light sources, which may have dozens of X-ray beamlines and many experiments going on simultaneously, the current version of LCLS has just one powerful beam, a billion times brighter than any available before, whose pulses arrive up to 120 times per second. In theory this limits the facility to doing one experiment at a time.

    But in the seven years since it opened, scientists and engineers have come up with a number of ways to get around that limitation, such as splitting the beam so it can be delivered to two or more experiments at once. At the same time, they reduced the down time between experiments by scheduling similar experiments back to back, so they don’t have to change out equipment as often. These and other measures increased the number of experiments run per year by 72 percent from 2014 to 2016, and LCLS recently passed the milestone of hosting more than 1,000 users per year.

    LCLS-II will add a second X-ray laser beam, further increasing the facility’s capacity. By continuing to find ways to squeeze in more experiments while making the way people interact with LCLS more straightforward, Fuoss said, “We can improve productivity and allow the scientific users to have a more hands-on role in the actual data collection. That will both reduce the load on the LCLS staff and lead to a better experience for the scientists who are coming here to use it.“

    LCLS and SSRL are DOE Office of Science User Facilities.

    For questions or comments, contact the SLAC Office of Communications at communications@slac.stanford.edu.

    See the full article here .

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    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 DOE’s Office of Science.
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  • richardmitnick 8:08 am on April 25, 2017 Permalink | Reply
    Tags: , , SLAC   

    From SLAC: “Machine Learning Dramatically Streamlines Search for More Efficient Chemical Reactions” 


    SLAC Lab

    April 24, 2017
    Glennda Chui

    1
    A diagram shows the many possible paths one simple catalytic reaction can theoretically take – in this case, conversion of syngas, which is a combination of carbon dioxide (CO2) and carbon monoxide (CO), to acetaldehyde. Machine learning allowed SUNCAT theorists to prune away the least likely paths and identify the most likely one (red) so scientists can focus on making it more efficient. (Zachary Ulissi/SUNCAT)

    Even a simple chemical reaction can be surprisingly complicated. That’s especially true for reactions involving catalysts, which speed up the chemistry that makes fuel, fertilizer and other industrial goods. In theory, a catalytic reaction may follow thousands of possible paths, and it can take years to identify which one it actually takes so scientists can tweak it and make it more efficient.

    Now researchers at the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University have taken a big step toward cutting through this thicket of possibilities. They used machine learning – a form of artificial intelligence – to prune away the least likely reaction paths, so they can concentrate their analysis on the few that remain and save a lot of time and effort.

    The method will work for a wide variety of complex chemical reactions and should dramatically speed the development of new catalysts, the team reported in Nature Communications.

    ‘A Daunting Task’

    “Designing a novel catalyst to speed a chemical reaction is a very daunting task,” said Thomas Bligaard, a staff scientist at the SUNCAT Center for Interface Science and Catalysis, a joint SLAC/Stanford institute where the research took place. “There’s a huge amount of experimental work that normally goes into it.”

    For instance, he said, finding a catalyst that turns nitrogen from the air into ammonia – considered one of the most important developments of the 20th century because it made the large-scale production of fertilizer possible, helping to launch the Green Revolution – took decades of testing various reactions one by one.

    Even today, with the help of supercomputer simulations that predict the results of reactions by applying theoretical models to huge databases on the behavior of chemicals and catalysts, the search can take years, because until now it has relied largely on human intuition to pick possible winners out of the many available reaction paths.

    “We need to know what the reaction is, and what are the most difficult steps along the reaction path, in order to even think about making a better catalyst,” said Jens Nørskov, a professor at SLAC and Stanford and director of SUNCAT.

    “We also need to know whether the reaction makes only the product we want or if it also makes undesirable byproducts. We’ve basically been making reasonable assumptions about these things, and we really need a systematic theory to guide us.”

    Trading Human Intuition for Machine Learning

    For this study, the team looked at a reaction that turns syngas, a combination of carbon monoxide and hydrogen, into fuels and industrial chemicals. The syngas flows over the surface of a rhodium catalyst, which like all catalysts is not consumed in the process and can be used over and over. This triggers chemical reactions that can produce a number of possible end products, such as ethanol, methane or acetaldehyde.

    “In this case there are thousands of possible reaction pathways – an infinite number, really – with hundreds of intermediate steps,” said Zachary Ulissi, a postdoctoral researcher at SUNCAT. “Usually what would happen is that a graduate student or postdoctoral researcher would go through them one at a time, using their intuition to pick what they think are the most likely paths. This can take years.”

    The new method ditches intuition in favor of machine learning, where a computer uses a set of problem-solving rules to learn patterns from large amounts of data and then predict similar patterns in new data. It’s a behind-the-scenes tool in an increasing number of technologies, from self-driving cars to fraud detection and online purchase recommendations.

    Rapid Weeding

    The data used in this process came from past studies of chemicals and their properties, including calculations that predict the bond energies between atoms based on principles of quantum mechanics. The researchers were especially interested in two factors that determine how easily a catalytic reaction proceeds: How strongly the reacting chemicals bond to the surface of the catalyst and which steps in the reaction present the most significant barriers to going forward. These are known as rate-limiting steps.

    A reaction will seek out the path that takes the least energy, Ulissi explained, much like a highway designer will choose a route between mountains rather than waste time looking for an efficient way to go over the top of a peak. With machine learning the researchers were able to analyze the reaction pathways over and over, each time eliminating the least likely paths and fine-tuning the search strategy for the next round.

    Once everything was set up, Ulissi said, “It only took seconds or minutes to weed out the paths that were not interesting. In the end there were only about 10 reaction barriers that were important.” The new method, he said, has the potential to reduce the time needed to identify a reaction pathway from years to months.

    Andrew Medford, a former SUNCAT graduate student who is now an assistant professor at the Georgia Institute of Technology, also contributed to this research, which was funded by the DOE Office of Science.

    See the full article here .

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    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 DOE’s Office of Science.
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  • richardmitnick 7:34 am on April 20, 2017 Permalink | Reply
    Tags: SLAC, Virtual tour of LCLS   

    From SLAC: “Virtual Tours of LCLS” 


    SLAC Lab

    The Linac Coherent Light Source (LCLS) at SLAC allows scientists to see the world in femtosecond resolution. Click on the images below to take virtual tours of the Undulator Hall and the Near Experimental Hall (NEH) at LCLS. Also check out our LCLS album on Flickr for photos of the facility.

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    Undulator Hall View the video images. Click on the blue circle to navigate.

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    Near Experimental Hall View the video images. Click on the blue circle to navigate.

    See the full article here .

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    SLAC Campus
    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 DOE’s Office of Science.
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  • richardmitnick 1:45 pm on April 18, 2017 Permalink | Reply
    Tags: , , , Gabriella Carini, How do you catch femtosecond light?, , , SLAC, , ,   

    From SLAC: “How do you catch femtosecond light?” 


    SLAC Lab

    1
    Gabriella Carini
    Staff Scientist
    Joined SLAC: 2011
    Specialty: Developing detectors that capture light from X-ray sources
    Interviewed by: Amanda Solliday

    Gabriella Carini enjoys those little moments—after hours and hours of testing in clean rooms, labs and at X-ray beamlines—when she first sees an instrument work.

    She earned her PhD in electronic engineering at the University of Palermo in Italy and now heads the detectors department at the Linac Coherent Light Source (LCLS), the X-ray free-electron laser at SLAC.

    SLAC/LCLS

    Scientists from around the world use the laser to probe natural processes that occur in tiny slivers of time. To see on this timescale, they need a way to collect the light and convert it into data that can be examined and interpreted.

    It’s Carini’s job to make sure LCLS has the right detector equipment at hand to catch the “precious”, very intense laser pulses, which may last only a few femtoseconds.

    When the research heads in new directions, as it constantly does, this requires her to look for fresh technology and turn these ideas into reality.

    When did you begin working with detectors?

    I moved to the United States as a doctoral student. My professor at the time suggested I join a collaboration at Brookhaven National Laboratory, where I started developing gamma ray detectors to catch radioactive materials.

    Radioactive materials give off gamma rays as they decay, and gamma rays are the most energetic photons, or particles of light. The detectors I worked on were made from cadmium zinc telluride, which has very good stopping power for highly energetic photons. These detectors can identify radioactive isotopes for security—such as the movement of nuclear materials—and contamination control, but also gamma rays for medical and astrophysical observations.

    We had some medical projects going on at the time, too, with detectors that scan for radioactive tracers used to map tissues and organs with positron emission tomography.

    From gamma ray detectors, I then moved to X-rays, and I began working on the earliest detectors for LCLS.

    How do you explain your job to someone outside the X-ray science community?

    I say, “There are three ingredients for an experiment—the source, the sample and the detector.”

    You need a source of light that illuminates your sample, which is the problem you want to solve or investigate. To understand what is happening, you have to be able to see the signal produced by the light as it interacts with the sample. That’s where the detector comes in. For us, the detector is like the “eyes” of the experimental set-up.

    What do you like most about your work?

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    There’s always a way we can help researchers optimize their experiments, tweak some settings, do more analysis and correction.

    This is important because scientists are going to encounter a lot of different types of detectors if they work at various X-ray facilities.

    I like to have input from people who are running the experiments. Because I did experiments myself as a graduate student, I’m very sensitive to whether a system is user-friendly. If you don’t make something that researchers can take the best advantage of, then you didn’t do your job fully.

    And detectors are never perfect, no matter which one you buy or build.

    There are a lot of people who have to come together to make a detector system. It’s not one person’s work. It’s many, many people with lots of different expertise. You need to have lots of good interpersonal skills.

    What are some of the challenges of creating detectors for femtosecond science?

    In more traditional X-ray sources the photons arrive distributed over time, one after the other, but when you work with ultrafast laser pulses like the ones from LCLS, all your information about a sample arrives in a few femtoseconds. Your detector has to digest this entire signal at once, process the information and send it out before another pulse comes. This requires deep understanding of the detector physics and needs careful engineering. You need to optimize the whole signal chain from the sensor to the readout electronics to the data transmission.

    We also have mechanical challenges because we have to operate in very unusual conditions: intense optical lasers, injectors with gas and liquids, etc. In many cases we need to use special filters to protect the detectors from these sources of contamination.

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    And often, you work in vacuum. With “soft” or low-energy X-rays, they are absorbed very quickly in air. Your entire system has to be vacuum-compatible. With many of our substantial electronics, this requires some care.

    So there are lots of things to take into account. Those are just a few examples. It’s very complicated and can vary quite a bit from experiment to experiment.

    Is there a new project you are really excited about?

    All of LCLS-II—this fills my life! We’re coming up with new ideas and new technologies for SLAC’s next X-ray laser, which will have a higher firing rate—up to a million pulses per second. For me, this is a multidimensional puzzle. Every science case and every instrument has its own needs and we have to find a route through the many options and often-competing parameters to achieve our goals.

    X-ray free-electron lasers are a big driver for detector development. Ten years ago, no one would have talked about X-ray cameras delivering 10,000 pictures per second. The new X-ray lasers are really a game-changer in developing detectors for photon science, because they require detectors that are just not readily available.

    LCLS-II will be challenging, but it’s exciting. For me, it’s thinking about what we can do now for the very first day of operation. And while doing that, we need to keep pushing the limits of what we have to do next to take full advantage of our new machine.

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    SLAC LCLS-II

    See the full article here .

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    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 DOE’s Office of Science.
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  • richardmitnick 3:55 pm on April 17, 2017 Permalink | Reply
    Tags: , , , , SLAC, , , ,   

    From SLAC: “SLAC’s X-ray Laser Glimpses How Electrons Dance with Atomic Nuclei in Materials” 


    SLAC Lab

    September 22, 2016

    Studies Could Help Design and Control Materials with Intriguing Properties, Including Novel Electronics, Solar Cells and Superconductors.

    From hard to malleable, from transparent to opaque, from channeling electricity to blocking it: Materials come in all types. A number of their intriguing properties originate in the way a material’s electrons “dance” with its lattice of atomic nuclei, which is also in constant motion due to vibrations known as phonons.

    This coupling between electrons and phonons determines how efficiently solar cells convert sunlight into electricity. It also plays key roles in superconductors that transfer electricity without losses, topological insulators that conduct electricity only on their surfaces, materials that drastically change their electrical resistance when exposed to a magnetic field, and more.

    At the Department of Energy’s SLAC National Accelerator Laboratory, scientists can study these coupled motions in unprecedented detail with the world’s most powerful X-ray laser, the Linac Coherent Light Source (LCLS). LCLS is a DOE Office of Science User Facility.

    SLAC/LCLS

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    An illustration shows how laser light excites electrons (white spheres) in a solid material, creating vibrations in its lattice of atomic nuclei (black and blue spheres). SLAC’s LCLS X-ray laser reveals the ultrafast “dance” between electrons and vibrations that accounts for many important properties of materials. (SLAC National Accelerator Laboratory)

    “It has been a long-standing goal to understand, initiate and control these unusual behaviors,” says LCLS Director Mike Dunne. “With LCLS we are now able to see what happens in these materials and to model complex electron-phonon interactions. This ability is central to the lab’s mission of developing new materials for next-generation electronics and energy solutions.”

    LCLS works like an extraordinary strobe light: Its ultrabright X-rays take snapshots of materials with atomic resolution and capture motions as fast as a few femtoseconds, or millionths of a billionth of a second. For comparison, one femtosecond is to a second what seven minutes is to the age of the universe.

    Two recent studies made use of these capabilities to study electron-phonon interactions in lead telluride, a material that excels at converting heat into electricity, and chromium, which at low temperatures has peculiar properties similar to those of high-temperature superconductors.

    Turning Heat into Electricity and Vice Versa

    Lead telluride, a compound of the chemical elements lead and tellurium, is of interest because it is a good thermoelectric: It generates an electrical voltage when two opposite sides of the material have different temperatures.

    “This property is used to power NASA space missions like the Mars rover Curiosity and to convert waste heat into electricity in high-end cars,” says Mariano Trigo, a staff scientist at the Stanford PULSE Institute and the Stanford Institute for Materials and Energy Sciences (SIMES), both joint institutes of Stanford University and SLAC. “The effect also works in the opposite direction: An electrical voltage applied across the material creates a temperature difference, which can be exploited in thermoelectric cooling devices.”

    Mason Jiang, a recent graduate student at Stanford, PULSE and SIMES, says, “Lead telluride is exceptionally good at this. It has two important qualities: It’s a bad thermal conductor, so it keeps heat from flowing from one side to the other, and it’s also a good electrical conductor, so it can turn the temperature difference into an electric current. The coupling between lattice vibrations, caused by heat, and electron motions is therefore very important in this system. With our study at LCLS, we wanted to understand what’s naturally going on in this material.”

    In their experiment, the researchers excited electrons in a lead telluride sample with a brief pulse of infrared laser light, and then used LCLS’s X-rays to determine how this burst of energy stimulated lattice vibrations.

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    This illustration shows the arrangement of lead and tellurium atoms in lead telluride, an excellent thermoelectric that efficiently converts heat into electricity and vice versa. In its normal state (left), lead telluride’s structure is distorted and has a relatively large degree of lattice vibrations (blurring). When scientists hit the sample with a laser pulse, the structure became more ordered (right). The results elucidate how electrons couple with these distortions – an interaction that is crucial for lead telluride’s thermoelectric properties. (SLAC National Accelerator Laboratory)

    “Lead telluride sits at the precipice of a coupled electronic and structural transformation,” says principal investigator David Reis from PULSE, SIMES and Stanford. “It has a tendency to distort without fully transforming – an instability that is thought to play an important role in its thermoelectric behavior. With our method we can study the forces involved and literally watch them change in response to the infrared laser pulse.”

    The scientists found that the light pulse excites particular electronic states that are responsible for this instability through electron-phonon coupling. The excited electrons stabilize the material by weakening certain long-range forces that were previously associated with the material’s low thermal conductivity.

    “The light pulse actually walks the material back from the brink of instability, making it a worse thermoelectric,” Reis says. “This implies that the reverse is also true – that stronger long-range forces lead to better thermoelectric behavior.”

    The researchers hope their results, published July 22 in Nature Communications, will help them find other thermoelectric materials that are more abundant and less toxic than lead telluride.

    Controlling Materials by Stimulating Charged Waves

    The second study looked at charge density waves – alternating areas of high and low electron density across the nuclear lattice – that occur in materials that abruptly change their behavior at a certain threshold. This includes transitions from insulator to conductor, normal conductor to superconductor, and from one magnetic state to another.

    These waves don’t actually travel through the material; they are stationary, like icy waves near the shoreline of a frozen lake.

    “Charge density waves have been observed in a number of interesting materials, and establishing their connection to material properties is a very hot research topic,” says Andrej Singer, a postdoctoral fellow in Oleg Shpyrko’s lab at the University of California, San Diego. “We’ve now shown that there is a way to enhance charge density waves in crystals of chromium using laser light, and this method could potentially also be used to tweak the properties of other materials.”

    This could mean, for example, that scientists might be able to switch a material from a normal conductor to a superconductor with a single flash of light. Singer and his colleagues reported their results on July 25 in Physical Review Letters.

    The research team used the chemical element chromium as a simple model system to study charge density waves, which form when the crystal is cooled to about minus 280 degrees Fahrenheit. They stimulated the chilled crystal with pulses of optical laser light and then used LCLS X-ray pulses to observe how this stimulation changed the amplitude, or height, of the charge density waves.

    “We found that the amplitude increased by up to 30 percent immediately after the laser pulse,” Singer says. “The amplitude then oscillated, becoming smaller and larger over a period of 450 femtoseconds, and it kept going when we kept hitting the sample with laser pulses. LCLS provides unique opportunities to study such process because it allows us to take ultrafast movies of the related structural changes in the lattice.”

    Based on their results, the researchers suggested a mechanism for the amplitude enhancement: The light pulse interrupts the electron-phonon interactions in the material, causing the lattice to vibrate. Shortly after the pulse, these interactions form again, which boosts the amplitude of the vibrations, like a pendulum that swings farther out when it receives an extra push.

    A Bright Future for Studies of the Electron-Phonon Dance

    Studies like these have a high priority in solid-state physics and materials science because they could pave the way for new materials and provide new ways to control material properties.

    With its 120 ultrabright X-ray pulses per second, LCLS reveals the electron-phonon dance with unprecedented detail. More breakthroughs in the field are on the horizon with LCLS-II – a next-generation X-ray laser under construction at SLAC that will fire up to a million X-ray flashes per second and will be 10,000 times brighter than LCLS.

    “LCLS-II will drastically increase our chances of capturing these processes,” Dunne says. “Since it will also reveal subtle electron-phonon signals with much higher resolution, we’ll be able to study these interactions in much greater detail than we can now.”

    Other research institutions involved in the studies were University College Cork, Ireland; Imperial College London, UK; Duke University; Oak Ridge National Laboratory; RIKEN Spring-8 Center, Japan; University of Tokyo, Japan; University of Michigan; and University of Kiel, Germany. Funding sources included DOE Office of Science; Science Foundation Ireland; Volkswagen Foundation, Germany; and Federal Ministry of Education and Research, Germany. Preliminary X-ray studies on lead telluride were performed at SLAC’s Stanford Synchrotron Radiation Lightsource (SSRL), a DOE Office of Science User Facility, and at the Spring-8 Angstrom Compact Free-electron Laser (SACLA), Japan.

    SLAC/SSRL

    SACLA Free-Electron Laser Riken Japan


    his movie introduces LCLS-II, a future light source at SLAC. It will generate over 8,000 times more light pulses per second than today’s most powerful X-ray laser, LCLS, and produce an almost continuous X-ray beam that on average will be 10,000 times brighter. (SLAC National Accelerator Laboratory)

    See the full article here .

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    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 DOE’s Office of Science.
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  • richardmitnick 9:23 pm on April 11, 2017 Permalink | Reply
    Tags: , , , , SLAC, , , Theory Institute for Materials and Energy Spectroscopies (TIMES), X-ray spectroscopy,   

    From SLAC: “New SLAC Theory Institute Aims to Speed Research on Exotic Materials at Light Sources” 


    SLAC Lab

    April 11, 2017
    Glennda Chui

    A new institute at the Department of Energy’s SLAC National Accelerator Laboratory is using the power of theory to search for new types of materials that could revolutionize society – by making it possible, for instance, to transmit electricity over power lines with no loss.

    The Theory Institute for Materials and Energy Spectroscopies (TIMES) focuses on improving experimental techniques and speeding the pace of discovery at West Coast X-ray facilities operated by SLAC and by Lawrence Berkeley National Laboratory, its DOE sister lab across the bay.

    But the institute aims to have a much broader impact on studies aimed at developing new materials for energy and other technological applications by making the tools it develops available to scientists around the world.

    TIMES opened in August 2016 as part of the Stanford Institute for Materials and Energy Sciences (SIMES), a DOE-funded institute operated jointly with Stanford.

    Materials that Surprise

    “We’re interested in materials with remarkable properties that seem to emerge out of nowhere when you arrange them in particular ways or squeeze them down into a single, two-dimensional layer,” says Thomas Devereaux, a SLAC professor of photon science who directs both TIMES and SIMES.

    This general class of materials is known as “quantum materials.” Some of the best-known examples are high-temperature superconductors, which conduct electricity with no loss; topological insulators, which conduct electricity only along their surfaces; and graphene, a form of pure carbon whose superior strength, electrical conductivity and other surprising qualities derive from the fact that it’s just one layer of atoms thick.

    In another research focus, Devereaux says, “We want to see what happens when you push materials far beyond their resting state – out of equilibrium, is the way we put it – by exciting them in various ways with pulses of X-ray light at facilities known as light sources.

    “This tells you how materials will behave under realistic operating conditions, for instance in a lightweight airplane or a new type of battery. Understanding and controlling out-of-equilibrium behavior and learning how novel properties emerge in complex materials are two of the scientific grand challenges in our field, and light sources are ideal places to do this work.”

    Joining Forces With Light Sources

    A key part of the institute’s work is to use theory and computation to improve experimental techniques – especially X-ray spectroscopy, which probes the chemical composition and electronic structure of materials – in order to make research at light sources more productive.

    “We are in a golden age of X-ray spectroscopy, in which many billions of dollars have been invested worldwide to develop new X-ray and neutron sources that allow us to study very small details and very fast processes in materials,” Devereaux says. “In fact, we are on the threshold of being able to control matter at a much deeper level than ever possible before.

    “But while X-ray spectroscopy has a long history of collaboration between experimentalists and theorists, there has not been a companion theory institute anywhere. TIMES fills this gap. It aims to solidify collaboration and development of new methods and tools for theory relevant to this new landscape.”

    Devereaux, a theorist who uses computation to study quantum materials, came to SLAC 10 years ago from the University of Waterloo in Canada to work more closely with researchers at three light sources – SLAC’s Stanford Synchrotron Radiation Lightsource (SSRL), Berkeley Lab’s Advanced Light Source (ALS) and the Linac Coherent Light Source (LCLS), the world’s first X-ray free-electron laser, which at the time was under construction at SLAC. Opened for research in 2009, LCLS gives scientists access to pulses a billion times brighter than any available before and that arrive up to 120 times per second, opening whole new avenues for research.

    SLAC/SSRL

    LBNL/ALS

    SLAC LCLS

    SLAC/LCLS II

    With LCLS, Devereaux says, “It became clear that we had an unprecedented opportunity to study materials that have been pushed farther away from equilibrium than was ever possible before.”

    Basic Questions and Practical Answers

    The DOE-funded theory institute has hired two staff scientists, Chunjing Jia and Das Pemmaraju, and works closely with SLAC staff scientists Brian Moritz and Hongchen Jiang and with a number of scientists at the three light sources.

    “We have two main goals,” Jia says. “One is to use X-ray spectroscopy and other techniques to look at practical materials, like the ones in batteries – to study the charging and discharging process and see how the structure of the battery changes, for instance. The second is to understand the fundamental underlying physics principles that govern the behavior of materials.”

    Eventually, she added, theorists want to understand those physics principles so well that they can predict the results of high-priority experiments at facilities that haven’t even been built yet – for instance at LCLS-II, a major upgrade to LCLS that will add a much brighter X-ray laser beam that fires up to a million pulses per second. These predictions have the potential to make experiments at new facilities much more productive and efficient.

    Running Experiments in Supercomputers

    Theoretical work can involve a lot of math and millions of hours of supercomputer time, as theorists struggle to clarify how the fundamental laws of quantum mechanics apply to the materials they are investigating, Pemmaraju says.

    “We use these laws in a form that can be simulated on a computer to make predictions about new materials and their properties,” he says. “The full richness and complexity of the theory are still being discovered, and its equations can only be solved approximately with the aid of supercomputers.”

    Jia adds that you can think of these computer simulations as numerical experiments – working “in silico,” rather than at a lab bench. By simulating what’s going on in a material, scientists can decide which of all the experimental options are the best ones, saving both time and money.

    The institute’s core research team includes theorists Joel Moore of the University of California, Berkeley and John Rehr of the University of Washington. Rehr is the developer of FEFF, an efficient and widely accessible software code that is used by the X-ray light source community worldwide. Devereaux says the plan is to establish a center for FEFF within the institute, which will serve as a home for its further development and for making those advances widely available to theorists and experimentalists at various levels of sophistication.

    TIMES and SIMES are funded by the DOE Office of Science, and the three light sources – ALS, SSRL and LCLS – are DOE Office of Science User Facilities.

    See the full article here .

    Please help promote STEM in your local schools.

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    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 DOE’s Office of Science.
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  • richardmitnick 8:49 pm on January 31, 2017 Permalink | Reply
    Tags: SLAC,   

    From SLAC: “Taking Down a Giant: 699 Tons of SLAC’s Accelerator Removed for Upgrade” 


    SLAC Lab

    January 31, 2017

    For the first time in more than 50 years, a door that is opened at the western end of the historic linear accelerator at the Department of Energy’s SLAC National Accelerator Laboratory casts light on four empty walls stretching as far as the eye can see.

    This end of the linac – a full kilometer of it – has been stripped of all its equipment both above and below ground. Over the next two years it will be re-equipped with new technology to power another wonder of modern science: an X-ray laser that will fire a million pulses per second.

    2
    Illustration of an electron beam traveling through a niobium cavity – a key component of SLAC’s future LCLS-II X-ray laser. Kept at minus 456 degrees Fahrenheit, a temperature at which niobium conducts electricity without losses, these cavities will power a highly energetic electron beam that will create up to 1 million X-ray flashes per second – more than any other current or planned X-ray laser. (SLAC National Accelerator Laboratory)

    “It was a tremendous effort by the project team and contractors,” Javier Sevilla, project manager for equipment removal, said. “From July to December, 50 workers a day were on site to disassemble and clear the gallery and tunnel.”

    “It was a tremendous effort by the project team and contractors,” Javier Sevilla, project manager for equipment removal, said. “From July to December, 50 workers a day were on site to disassemble and clear the gallery and tunnel.””It was a tremendous effort by the project team and contractors,” Javier Sevilla, project manager for equipment removal, said. “From July to December, 50 workers a day were on site to disassemble and clear the gallery and tunnel.”


    Access mp4 video here.

    The 2-mile linac is a familiar sight to motorists who pass over it on Interstate 280 near Sand Hill Road in Menlo Park. For decades, it accelerated electrons for experiments that explored the fundamental nature of matter and resulted in three Nobel prizes: two for the discovery of subatomic particles and one for confirming that protons and neutrons are made of quarks.

    Starting in 2006, the final kilometer was converted into the Linac Coherent Light Source, a DOE Office of Science User Facility that uses the original accelerator equipment to generate X-ray pulses for a free-electron laser.

    Starting in 2006, the final kilometer was converted into the Linac Coherent Light Source, a DOE Office of Science User Facility that uses the original accelerator equipment to generate X-ray pulses for a free-electron laser.

    Based on the extraordinary success of LCLS to date, the DOE recently approved a billion-dollar upgrade, LCLS-II, that will require the installation of a new, superconducting accelerator, to be built at the west end of the linac.

    699 Tons in 106 Truckloads

    The first one-third of the accelerator housing, located 25 feet below ground, has been stripped of aluminum alignment pipes, copper accelerator tubes and a complex maze of cables and electronics that turned a physicist’s dream into the first beams of accelerating electrons in 1965.

    Over the past several months, 699 tons of materials were removed from tunnel and gallery, amounting to 106 truckloads, according to Carole Fried, deputy project manager for the removal and disposition of the equipment.

    “More than half – about 59 percent – was recycled,” she said. “Over 400 tons of steel, scrap metal, wire, copper and aluminum, representing a value of more than $250,000.”

    The bulk of the equipment that was removed had been installed in the original 1960s linac construction. (For a detailed look at the accelerator fabrication, see this 1967 film.) The accelerator underwent numerous changes over the decades, however, including the addition of the SLAC Energy Doublers, which boosted the power to the accelerator in the 1970s, and the installation of upgraded klystrons – microwave tubes that power the accelerator – as part of the SLAC Linear Collider constructed in 1983.

    “Over the years many of the controls electronics have been replaced as well, so we removed components from every era of SLAC’s operation,” SLAC’s Scott DeBarger said.

    DeBarger oversaw the relocation of equipment before equipment removal began. Between April and July, more than 5,000 items were recovered– including klystrons, magnets, copper waveguides, vacuum pumps, control systems, position monitors and more – to be used in current and future projects at the lab.

    3
    LCLS-II. The Future is Supercool

    Later this year, the empty tunnel will be refurnished with state-of-the-art cryomodules that will form the superconducting portion of the upgrade to SLAC’s Linac Coherent Light Source, known as LCLS-II. The modules will be filled with liquid helium to cool the cavities to a chilly minus 456 degrees Fahrenheit. The ultracold technology will be used to create bursts of high-energy electrons 8,000 times faster than its predecessor and generate X-ray beams that are 10,000 times brighter.

    The cryomodules are being built at Fermi National Accelerator Laboratory [FNAL] and the Thomas Jefferson National Accelerator Facility [JLab].

    4
    Working on the string of the LCLS-II prototype cryomodule at FNAL.

    Before they are delivered to SLAC and installed, new infrastructure will go into the accelerator tunnel, including hookups to water and power. Above ground, solid-state microwave amplifiers will replace klystrons in the gallery.

    “LCLS-II is an impressive undertaking that relies on many teams, multiple successful phases and important collaborations with our partners – Argonne National Laboratory, Lawrence Berkeley National Lab, Fermilab and Jefferson Lab – and Cornell University,” said John Galayda, head of the LCLS-II project team. “We are making steady progress toward the start of operations in 2020.

    For questions or comments, contact the SLAC Office of Communications at communications@slac.stanford.edu.

    See the full article here .

    Please help promote STEM in your local schools.

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    SLAC Campus
    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 DOE’s Office of Science.
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  • richardmitnick 3:21 pm on December 26, 2016 Permalink | Reply
    Tags: , , , , Researchers Use World's Smallest Diamonds to Make Wires Three Atoms Wide, SLAC   

    From SLAC: “Researchers Use World’s Smallest Diamonds to Make Wires Three Atoms Wide” 


    SLAC Lab

    December 26, 2016

    LEGO-style Building Method Has Potential for Making One-Dimensional Materials with Extraordinary Properties

    1
    Fuzzy white clusters of nanowires on a lab bench, with a penny for scale. Assembled with the help of diamondoids, the microscopic nanowires can be seen with the naked eye because the strong mutual attraction between their diamondoid shells makes them clump together, in this case by the millions. At top right, an image made with a scanning electron microscope shows nanowire clusters magnified 10,000 times. (SEM image by Hao Yan/SIMES; photo by SLAC National Accelerator Laboratory)

    Scientists at Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory have discovered a way to use diamondoids – the smallest possible bits of diamond – to assemble atoms into the thinnest possible electrical wires, just three atoms wide.

    By grabbing various types of atoms and putting them together LEGO-style, the new technique could potentially be used to build tiny wires for a wide range of applications, including fabrics that generate electricity, optoelectronic devices that employ both electricity and light, and superconducting materials that conduct electricity without any loss. The scientists reported their results today in Nature Materials.

    “What we have shown here is that we can make tiny, conductive wires of the smallest possible size that essentially assemble themselves,” said Hao Yan, a Stanford postdoctoral researcher and lead author of the paper. “The process is a simple, one-pot synthesis. You dump the ingredients together and you can get results in half an hour. It’s almost as if the diamondoids know where they want to go.”

    2
    This animation shows molecular building blocks joining the tip of a growing nanowire. Each block consists of a diamondoid – the smallest possible bit of diamond – attached to sulfur and copper atoms (yellow and brown spheres). Like LEGO blocks, they only fit together in certain ways that are determined by their size and shape. The copper and sulfur atoms form a conductive wire in the middle, and the diamondoids form an insulating outer shell. (SLAC National Accelerator Laboratory)

    The Smaller the Better

    3

    Illustration of a cluster of nanowires assembled by diamondoids
    An illustration shows a hexagonal cluster of seven nanowires assembled by diamondoids. Each wire has an electrically conductive core made of copper and sulfur atoms (brown and yellow spheres) surrounded by an insulating diamondoid shell. The natural attraction between diamondoids drives the assembly process. (H. Yan et al., Nature Materials)

    Although there are other ways to get materials to self-assemble, this is the first one shown to make a nanowire with a solid, crystalline core that has good electronic properties, said study co-author Nicholas Melosh, an associate professor at SLAC and Stanford and investigator with SIMES, the Stanford Institute for Materials and Energy Sciences at SLAC.

    The needle-like wires have a semiconducting core – a combination of copper and sulfur known as a chalcogenide – surrounded by the attached diamondoids, which form an insulating shell.

    Their minuscule size is important, Melosh said, because a material that exists in just one or two dimensions – as atomic-scale dots, wires or sheets – can have very different, extraordinary properties compared to the same material made in bulk. The new method allows researchers to assemble those materials with atom-by-atom precision and control.

    The diamondoids they used as assembly tools are tiny, interlocking cages of carbon and hydrogen. Found naturally in petroleum fluids, they are extracted and separated by size and geometry in a SLAC laboratory. Over the past decade, a SIMES research program led by Melosh and SLAC/Stanford Professor Zhi-Xun Shen has found a number of potential uses for the little diamonds, including improving electron microscope images and making tiny electronic gadgets.

    4
    Stanford graduate student Fei Hua Li, left, and postdoctoral researcher Hao Yan in one of the SIMES labs where diamondoids – the tiniest bits of diamond – were used to assemble the thinnest possible nanowires. (SLAC National Accelerator Laboratory)

    Constructive Attraction

    5
    Ball-and-stick models of diamondoid atomic structures in the SIMES lab at SLAC. SIMES researchers used the smallest possible diamondoid – adamantane, a tiny cage made of 10 carbon atoms – to assemble the smallest possible nanowires, with conductive cores just three atoms wide. (SLAC National Accelerator Laboratory)

    For this study, the research team took advantage of the fact that diamondoids are strongly attracted to each other, through what are known as van der Waals forces. (This attraction is what makes the microscopic diamondoids clump together into sugar-like crystals, which is the only reason you can see them with the naked eye.)

    They started with the smallest possible diamondoids – single cages that contain just 10 carbon atoms – and attached a sulfur atom to each. Floating in a solution, each sulfur atom bonded with a single copper ion. This created the basic nanowire building block.

    The building blocks then drifted toward each other, drawn by the van der Waals attraction between the diamondoids, and attached to the growing tip of the nanowire.

    “Much like LEGO blocks, they only fit together in certain ways that are determined by their size and shape,” said Stanford graduate student Fei Hua Li, who played a critical role in synthesizing the tiny wires and figuring out how they grew. “The copper and sulfur atoms of each building block wound up in the middle, forming the conductive core of the wire, and the bulkier diamondoids wound up on the outside, forming the insulating shell.”

    A Versatile Toolkit for Creating Novel Materials

    The team has already used diamondoids to make one-dimensional nanowires based on cadmium, zinc, iron and silver, including some that grew long enough to see without a microscope, and they have experimented with carrying out the reactions in different solvents and with other types of rigid, cage-like molecules, such as carboranes.

    The cadmium-based wires are similar to materials used in optoelectronics, such as light-emitting diodes (LEDs), and the zinc-based ones are like those used in solar applications and in piezoelectric energy generators, which convert motion into electricity.

    “You can imagine weaving those into fabrics to generate energy,” Melosh said. “This method gives us a versatile toolkit where we can tinker with a number of ingredients and experimental conditions to create new materials with finely tuned electronic properties and interesting physics.”

    Theorists led by SIMES Director Thomas Devereaux modeled and predicted the electronic properties of the nanowires, which were examined with X-rays at SLAC’s Stanford Synchrotron Radiation Lightsource, a DOE Office of Science User Facility, to determine their structure and other characteristics.

    The team also included researchers from the Stanford Department of Materials Science and Engineering, Lawrence Berkeley National Laboratory, the National Autonomous University of Mexico (UNAM) and Justus-Liebig University in Germany. Parts of the research were carried out at Berkeley Lab’s Advanced Light Source (ALS)

    LBNL ALS interior
    LBNL ALS

    and National Energy Research Scientific Computing Center (NERSC),

    NERSC CRAY Cori supercomputer
    NERSC

    both DOE Office of Science User Facilities. The work was funded by the DOE Office of Science and the German Research Foundation.

    See the full article here .

    Please help promote STEM in your local schools.

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    SLAC Campus
    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 DOE’s Office of Science.
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  • richardmitnick 9:23 am on December 15, 2016 Permalink | Reply
    Tags: , , , , SLAC, , X-ray crystallography,   

    From Stanford: “Masters of Crystallization” 

    Stanford University Name
    Stanford University

    March 24, 2016 [Stanford just put this in social media 12.14.16.]
    Glennda Chui

    When molecules won’t crystallize and technology confounds, who you gonna call?

    1
    Macromolecular Structure Knowledge Center at Stanford’s Shriram Center. From left: Ted Li, T.J. Lane, MSKC Director Marc C. Deller, Nick Cox, Timothy Rhorer, Zachary Rosenthal.

    2
    Researcher Ted Li examines a sample tray full of protein crystals under a microscope. Photo: SLAC National Accelerator Laboratory.

    Biology isn’t just for biologists anymore. That’s nowhere more apparent than in the newly furnished lab in room 097 of the Shriram Center basement, where flasks of bacterial and animal cells, snug in their incubators, are churning out proteins destined for jobs they may not have done in nature.

    Researchers who use this lab span a broad range of backgrounds and interests: Chemists searching for novel antibiotics. Chemical engineers developing biofuels. Doctors seeking new treatments for diabetes.

    Most of these highly skilled researchers have one thing in common: They have no idea how to grow the proteins and other large biomolecules that are essential to their research or how to prepare those proteins for X-ray studies that will reveal their structure and function.

    That’s where Marc Deller comes in.

    “I’m the lab manager, scientist, lab cleaner — I do everything, and I help people who don’t know how to use the equipment,” says Deller, who arrived in August to establish and direct the Macromolecular Structure Knowledge Center (MSKC). “I’m pretty much unboxing things every day and trying to get things plugged in.”

    With a doctorate from Oxford and years of protein-wrangling experience, he’s here to help Stanford faculty and students grow, purify and crystallize proteins and other big biomolecules so they can be probed with the SSRL synchrotron or the LCLS X-ray laser at SLAC National Accelerator Laboratory, just up the hill.

    SLAC/SSRL
    SLAC SSRL Tunnel
    “SLAC/SSRL

    SLAC/LCLS
    SLAC/LCLS

    SLAC jointly funds the center with Stanford ChEM-H, an interdisciplinary institute aimed at understanding human biology at a chemical level, and the services offered at MSKC augment help available from the expert staff at the SLAC X-ray facilities.

    X-ray crystallography has been a revolutionary tool for understanding how living things work, revealing the structures of more than 100,000 proteins, nucleic acids and their complexes over the past few decades and fueling the development of numerous life-saving medications.

    But it’s not always easy, as chemistry graduate student Ted Li can attest. The protein he’s studying — a natural catalyst found in soil bacteria that scientists hope to turn into an antibiotic factory — “is very resistant to crystallization. It’s very floppy and doesn’t want to pack,” says Li, who works in the lab of Chaitan Khosla, professor of chemistry and of chemical engineering. “So I need to find a way to force them to do that. Most of the things I’m doing these days are completely new to me, and Marc is my main mentor. He’ll actually go with me to SLAC and guide me in how to collect my data.”

    In its first six months, MSKC has already helped scientists with two dozen research projects, and Deller is eager to round up more. “From my experience of doing this for 20 years,” he says, “making the protein is definitely a bottleneck.”

    See the full article here .

    Please help promote STEM in your local schools.
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    Leland and Jane Stanford founded the University to “promote the public welfare by exercising an influence on behalf of humanity and civilization.” Stanford opened its doors in 1891, and more than a century later, it remains dedicated to finding solutions to the great challenges of the day and to preparing our students for leadership in today’s complex world. Stanford, is an American private research university located in Stanford, California on an 8,180-acre (3,310 ha) campus near Palo Alto. Since 1952, more than 54 Stanford faculty, staff, and alumni have won the Nobel Prize, including 19 current faculty members

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  • richardmitnick 7:49 pm on November 8, 2016 Permalink | Reply
    Tags: , , , SLAC   

    From SLAC: World’s Largest Camera for Astronomy 


    SLAC Lab

    1


    Access mp4 video here .

    Large Synoptic Survey Telescope

    Ranked as the top ground-based national priority for the field for the current decade, LSST is currently under construction in Chile. The U.S. Department of Energy’s SLAC National Accelerator Laboratory is leading the construction of the LSST camera – the largest digital camera ever built for astronomy. SLAC Professor Steven M. Kahn is the overall Director of the LSST project, and SLAC personnel are also participating in the data management. The National Science Foundation is the lead agency for construction of the LSST. Additional financial support comes from the Department of Energy and private funding raised by the LSST Corporation.

    LSST Science Goals
    What Will LSST Look At?

    The LSST will survey the entire visible southern sky every few days for a decade. Its vast public archive of data will dramatically advance our knowledge of the dark energy and dark matter that make up 95 percent of the universe, as well as galaxy formation and potentially hazardous asteroids.

    3

    Dark Matter

    Gravitational lensing is our best tool for finding dark matter. LSST’s power and large field of view will enable us to see weaker lenses, which are more common.

    Read more.

    4

    Dark Energy

    6

    LSST’s 18,000-square-degree coverage of billions of galaxies has the power to test differences in fundamental properties of space and time itself in different directions.

    Read more.

    The Solar System

    7

    The LSST will undertake a thorough exploration of our solar system with two goals in mind: learning how it originally formed, and protecting Earth from hazardous, near-flying asteroids.

    Read more.

    The Milky Way

    8

    Individual stars in the Milky Way and the galaxies nearby can be resolved by the LSST. These stars then provide a fossil record—a Rosetta Stone—that can be decoded to determine how these galaxies formed.

    Read more.

    The Changing Sky

    8

    The LSST will scan the sky repeatedly to great depth, enabling it to both discover new, distant transient events and to study variable objects throughout our universe.

    Read more.

    Camera Design
    Nuts and Bolts

    10

    Camera Overview

    About the size of a small SUV, the LSST camera is the largest camera ever constructed for astronomy. It is a large-aperture, wide-field optical camera that is capable of viewing light from the near ultraviolet to near infrared wavelengths.

    Length 9.8 ft (3 m)
    Height 5.5 ft (1.65 m)
    Weight 6200 lbs (2800 kg)
    Pixel Count 3200 megapixel
    Wavelength Range 320–1050 nm

    Note: 1 nm (nanometer) = 10-9 m or one-billionth of a meter

    Focal Plane

    The focal plane is the heart of the camera, where light from billions of galaxies comes to a focus. It consists of 189 charge-coupled device (CCD) sensors, arranged in a total of 21 3-by-3 square arrays mounted on platforms called rafts. The system is cooled to about -100 °C to minimize noise.

    The 64-cm-wide focal plane corresponds to a 3.5-degree field of view, which means the camera can capture more than 40 times the area of the full moon in the sky with each exposure.

    11

    Filter Changer

    The camera also contains a carousel that holds five on-board filters. Each of the filters can be individually swapped out in under two minutes and up to four times a night with the double-rail auto changer. The system also integrates with a manual load-lock changer to allow for a swap-out of a sixth filter.

    The optimized wavelength range for the LSST camera is 320–1050 nm (near ultraviolet to near infrared). This range is divided into six spectral bands labeled u-g-r-i-z-y, each associated with one of the filters. For example, an infrared, or “i” filter might be used to observe sources obscured by dust, since infrared wavelengths can pass through the dust.

    12

    There is more material here that I could not translate into useful data for thi post.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    SLAC Campus
    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 DOE’s Office of Science.
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