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  • richardmitnick 10:06 am on July 25, 2016 Permalink | Reply
    Tags: , , Electron injector for European XFEL exceeds expectations, , X-ray Technology   

    From XFEL: “Electron injector for European XFEL exceeds expectations” 

    XFEL bloc

    European XFEL

    25 July 2016
    No writer credit found

    First accelerator section successfully tested

    DESY has successfully concluded tests of the first section of the particle accelerator for the European XFEL. The so-called electron injector, which is 30 metres long, performed distinctly better than expected. The injector already completed a whole week under operating conditions. “Having gathered much valuable experience, we are now all set to start up the entire accelerator complex”, reports Winfried Decking, the machine coordinator at DESY. “This is a huge success for the entire accelerator team, together with our international partners.”

    1
    The diagnostic system produces elongated images of individual electron bunches and allows to analyse them in slices. DESY

    The bright X-ray light of the European XFEL is produced by small bunches of high-energy electrons which are brought to speed by a particle accelerator and then sent down an undulating magnetic path. At each magnetic bend in the path, the electron nunches emit X-rays which add up to a laser-like pulse in a self-amplifying manner.

    DESY is the main shareholder of the European XFEL GmbH and responsible, among other things, for building and operating the 2.1-kilometre particle accelerator. The injector is located at the very beginning of the accelerator to which it supplies tailor-made bunches of electrons. The quality of these electron bunches is crucial to the quality of the X-ray laser pulses at the experimental stations, 3.4 kilometres away. One important quality criterion is how narrowly the electron bunches can be focused. “This so-called emittance is some 40 percent better than specified”, reports Decking.

    2
    The injector is 30 metres long. Dirk Nölle / DESY

    Ten times every second, the injector produces a train of up to 2700 short bunches of electrons. To test the quality of the beam, a special diagnostic system picks out individual bunches. “We need only about four bunches per train to analyse the beam”, explains Decking. These bunches are tilted by a cavity before striking the diagnostic screen. The elongated image they leave behind as a result can be used to study the longitudinal structure of each bunch in detail. The analysis reveals the outstanding quality of the bunches.

    In the past seven months, the injector, which produced its first electron beam in December, has given the accelerator team an opportunity to get to know all major subsystems of the entire accelerator facility: “The injector includes all the subsystems that are used in the main accelerator too”, says Decking. “This meant we were able to test and familiarise ourselves with them.” All in all, he says, no major obstacles were encountered throughout the several months of its test operation. The injector went offline on Monday, so that it can be connected to the main accelerator, for which commissioning is planned to start in October 2016. The whole facility is expected to be available for experiments as from the summer of 2017.

    3
    View of DESY’s accelerator control centre, European XFEL section. Dirk Nölle / DESY

    Apart from DESY and European XFEL GmbH, the Centre national de la recherche scientifique CNRS in Orsay (France), the Commissariat à l’énergie atomique et aux énergies alternatives CEA in Saclay (France), the Istituto Nazionale di Fisica Nucleare INFN in Milan (Italy), the Narodowe Centrum Badań Jądrowych in Swierk (Poland), the Wrocław University of Technology WUT in Wrocław (Poland), the Instytut Fizyki Jądrowej IFJ-PAN in Krakow (Poland), the Institute for High-Energy Physics in Protvino (Russia), the Efremov Institute NIIEFA in St. Petersburg (Russia), the Budker Institute for Nuclear Physics BINP in Novosibirsk (Russia), the Institute for Nuclear Research INR in Moscow (Russia), the Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas CIEMAT in Madrid (Spain), the Universidad Politécnica de Madrid UPM in Madrid (Spain), the University of Stockholm (Sweden), the University of Uppsala (Sweden), and the Paul Scherrer Institute in Villigen (Switzerland) are also involved in the injector.

    See the full article here .

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    XFEL Campus

    The Hamburg area will soon boast a research facility of superlatives: The European XFEL will generate ultrashort X-ray flashes—27 000 times per second and with a brilliance that is a billion times higher than that of the best conventional X-ray radiation sources.

    The outstanding characteristics of the facility are unique worldwide. Starting in 2017, it will open up completely new research opportunities for scientists and industrial users.

     
  • richardmitnick 5:05 pm on July 15, 2016 Permalink | Reply
    Tags: , New Macromolecular Femtosecond Crystallography (MFX) station at LCLS, , X-ray Technology   

    From SLAC: “Research Begins at SLAC’s Newest X-ray Laser Experimental Station” 


    SLAC Lab

    July 14, 2016

    In First Study, Berkeley Lab Scientists Use the New Station to Examine Hemoglobin

    1
    Berkeley Lab and SLAC scientists (from left) Jake Koralek, Franklin Fuller, Sheraz Gul, Ernest Pastor and Jan Kern set up their experiment at the Macromolecular Femtosecond Crystallography (MFX) station at LCLS. (SLAC National Accelerator Laboratory)

    2
    SLAC scientists Daniel Damiani and Jason Koglin in the control room of the Macromolecular Femtosecond Crystallography (MFX) station. (SLAC National Accelerator Laboratory)

    A new X-ray laser experimental station at the Department of Energy’s SLAC National Accelerator Laboratory recently welcomed its first research group, scientists from Lawrence Berkeley National Laboratory.

    Members of the Berkeley Lab’s Yachandra/Yano research team ran the inaugural experiment from July 1 to 4. They used the X-ray laser to develop new spectroscopic tools, with an initial focus on studying an enzyme in blood known as hemoglobin. Hemoglobin allows oxygen to be carried around our bodies and gives red blood cells their distinctive color.

    In contrast, Macromolecular Femtosecond Crystallography (MFX) is blaze orange, following the LCLS tradition of personalizing each instrument at SLAC’s Linac Coherent Light Source (LCLS), a DOE Office of Science User Facility. LCLS is a hard X-ray free-electron laser that fires in pulses just a few millionths of a billionth of a second in length, offering a look at chemistry on the natural timescales of reactions.

    MFX is the seventh instrument at LCLS, and is designed to optimize the facility’s ability to investigate the innermost workings of the chemistry and biology that underpin the living world. MFX allows scientists to study complex molecules such as proteins with atomic resolution using a variety of experimental techniques.

    Scientists can take advantage of short X-ray pulses at MFX to limit sample damage during exposure. This can be particularly important, for example, when looking at metal-containing molecules that are more sensitive to damage by radiation.

    During the first experiment at MFX, the Berkeley Lab group studied the distribution of electrons and the bonds between iron and the surrounding atoms within hemoglobin. Many iron-containing enzymes transfer electrons from the iron to an oxygen molecule. This makes both the metal and the oxygen highly active, leading to other important biological reactions, said Franklin Fuller, a postdoctoral researcher at Berkeley Lab.

    “We want to know where these electrons travel throughout the course of the reactions,” said Fuller. “At MFX, we can use an experimental technique – called X-ray emission spectroscopy – that is sensitive to that.”

    Using the capabilities of the X-ray laser, they could look at the chemical changes as the reactions progress. The information collected from hemoglobin experiments can also be useful when examining other iron and metal-containing proteins that are important to both energy production and health.

    Fuller said it can be difficult to measure signals from these proteins, because they exist at very low concentrations. The signals tend to be weak.

    “The goal is to push our ability to examine low concentration samples that represent real-world situations, and that requires the high brilliance, high flux of LCLS,” Fuller said.

    The group was able to collect data with excellent quality, said Jan Kern, a scientist at Berkeley Lab and LCLS. They were able to examine the relationship between the many energies in the X-ray laser beam in each shot and the X-ray spectrum from the iron-containing hemoglobin, as well as some simpler iron compounds.

    “For a first experiment using a brand new beam line, instrument and hutch, data collection went remarkably smoothly,” said Kern. “Although we were nervous about being the first users, everything worked really well. We really appreciate the work done by the LCLS scientists and engineers.”

    The number of proposals for biology experiments at LCLS has rapidly increased during the past few years. MFX will help meet this growing demand by complementing the suite of LCLS instruments already in use for structural biology studies.

    The Berkeley Lab researchers will return to MFX later in July for another experiment, designed to look closely at water splitting during photosynthesis. Learning how water is ‘split’ into protons and oxygen in photosynthetic organisms by using light is critical for designing artificial systems that are important for solar-based renewable energy. The Berkeley Lab researchers are trying to understand the mechanism using simultaneous data collection for X-ray crystallography and X-ray emission spectroscopy. To do this, the researchers built a small conveyor belt to deliver droplets of the liquid samples into the beam line at MFX.

    The new experimental station is designed to handle challenging biological samples that are fundamentally important for medicine, chemistry and energy research. MFX aims to achieve higher throughput and user access with a versatile system that supports a few standard configurations compatible with a broad range of samples.

    Scientists from across SLAC (including LCLS, the Stanford Synchrotron Radiation Lightsource (SSRL) and the Bioscience Division) designed the MFX experimental station in close consultation with the user community. The project is supported by the DOE’s Office of Biological and Environmental Research and Office of Basic Energy Sciences, both part of the DOE Office of Science, in addition to Stanford University and the NIH National Institute of General Medical Sciences.

    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 7:25 am on June 30, 2016 Permalink | Reply
    Tags: , , , Color, X-ray Technology   

    From Argonne: “X-rays reveal the photonic crystals in butterfly wings that create color” 

    ANL Lab
    News from Argonne National Laboratory

    June 10, 2016 [This just appeared in social media.]
    Louise Lerner


    Access mp4 video here .

    Scientists used X-rays to discover what creates one butterfly effect: how the microscopic structures on the insect’s wings reflect light to appear as brilliant colors to the eye.

    1
    Researchers used powerful X-rays to take a molecular look at how the Kaiser-i-Hind butterfly’s wings reflect in brilliant iridescent green. Image: Shutterstock/Butterfly Hunter.

    2
    When you look very close up at a butterfly wing, you can see this patchwork map of lattices with slightly different orientations (colors added to illustrate the domains). Scientists think this structure, and the irregularities along the edges where they meet, helps create the brilliant “sparkle” of the wings. Image courtesy Ian McNulty/Science

    The results, published today in Science Advances, could help researchers mimic the effect for reflective coatings, fiber optics or other applications.

    We’ve long known that butterflies, lizards and opals all use complex structures called photonic crystals to scatter light and create that distinctive iridescent look. But we knew less about the particulars of how these natural structures grow and what they look like at very, very small sizes—and how we might steal their secrets to make our own technology.

    A powerful X-ray microscope at the Advanced Photon Source, a U.S. Department of Energy Office of Science User Facility, provided just such a view to scientists from the University of California-San Diego, Yale University and the DOE’s Argonne National Laboratory.

    ANL APS
    ANL/APS

    They took a tiny piece of a wing scale from the vivid green Kaiser-i-Hind butterfly, Teinopalpus imperialis, and ran X-ray studies to study the organization of the photonic crystals in the scale.

    At sizes far too small to be seen by the human eye, the scales look like a flat patchwork map with sections of lattices, or “domains,” that are highly organized but have slightly different orientations.

    “This explains why the scales appear to have a single color,” said UC-San Diego’s Andrej Singer, who led the work. “We also found tiny crystal irregularities that may enhance light-scattering properties, making the butterfly wings appear brighter.”

    These occasional irregularities appear as defects where the edges of the domains met each other.

    “We think this may indicate the defects grow as a result of the chirality —the left or right-handedness—of the chitin molecules from which butterfly wings are formed,” said coauthor Ian McNulty, an X-ray physicist with the Center for Nanoscale Materials at Argonne, also a DOE Office of Science User Facility.

    These crystal defects had never been seen before, he said.

    Defects sound as though they’re a problem, but they can be very useful for determining how a material behaves—helping it to scatter more green light, for example, or to concentrate light energy in other useful ways.

    “It would be interesting to find out whether this is an intentional result of the biological template for these things, and whether we can engineer something similar,” he said.

    The observations, including that there are two distinct kinds of boundaries between domains, could shed more light on how these structures assemble themselves and how we could mimic such growth to give our own materials new properties, the authors said.

    The X-ray studies provided a unique look because they are non-destructive—other microscopy techniques often require slicing the sample into paper-thin layers and staining it with dyes for contrast, McNulty said.

    “We were able to map the entire three-micron thickness of the scale intact,” McNulty said. (Three microns is about the width of a strand of spider silk.)

    The wing scales were studied at the 2-ID-B beamline at the Advanced Photon Source. The results are published in an article, Domain morphology, boundaries, and topological defects in biophotonic gyroid nanostructures of butterfly wing scales, in Science Advances. Other researchers on the study were Oleg Shpyrko, Leandra Boucheron and Sebastian Dietze (UC-San Diego); David Vine (Argonne/Berkeley National Laboratory); and Katharine Jensen, Eric Dufresne, Richard Prum and Simon Mochrie (Yale).

    The research was supported by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences.

    See the full article here .

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    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. For more visit http://www.anl.gov.

    The Advanced Photon Source at Argonne National Laboratory is one of five national synchrotron radiation light sources supported by the U.S. Department of Energy’s Office of Science to carry out applied and basic research to understand, predict, and ultimately control matter and energy at the electronic, atomic, and molecular levels, provide the foundations for new energy technologies, and support DOE missions in energy, environment, and national security. To learn more about the Office of Science X-ray user facilities, visit http://science.energy.gov/user-facilities/basic-energy-sciences/.

    Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science

    Argonne Lab Campus

     
    • Bill 9:19 am on July 10, 2016 Permalink | Reply

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  • richardmitnick 11:10 am on June 15, 2016 Permalink | Reply
    Tags: , , New X-ray method allows scientists to probe molecular explosions, , X-ray Technology   

    From ANL: “New X-ray method allows scientists to probe molecular explosions” 

    Argonne Lab
    News from Argonne National Laboratory

    June 15, 2016
    Jared Sagoff

    Summer blockbuster season is upon us, which means plenty of fast-paced films with lots of action. However, these aren’t new releases from Hollywood studios; they’re one type of new “movies” of atomic-level explosions that can give scientists new information about how X-rays interact with molecules.

    A team led by researchers from the U.S. Department of Energy’s (DOE’s) Argonne National Laboratory used the high-intensity, quick-burst X-rays provided by the Linac Coherent Light Source (LCLS) at SLAC National Accelerator Laboratory to look at how the atoms in a molecule change when the molecule is bombarded with X-rays.

    SLAC/LCLS
    SLAC/LCLS

    “The LCLS gives us a unique perspective on molecular dynamics because of the extremely brief X-ray pulses that we can use,” said Antonio Picon, an Argonne X-ray scientist and lead author. “We’re able to see how charge and energy can flow through a system with amazing precision.”

    By using a new method called X-ray pump/X-ray probe, the researchers were able to excite a specifically targeted inner-shell electron in a xenon atom bonded to two fluorine atoms. After the electron was excited out of its shell, the unbalanced positive charge in the rest of the molecule caused the molecule to spontaneously dissociate in a process known as “Coulomb explosion.”

    1
    Dynamics of the Coulomb explosion of argon clusters induced by intense femtosecond laser pulses. Kyoto University Institute for Chemical Research

    “The new X-ray pump/X-ray probe technique is so powerful because it allows us to shake the molecule at one point, and look at how it changes at a second point,” said Argonne X-ray scientist and study author Christoph Bostedt.

    The xenon difluoride molecule is only a first step for the technique. In the future, the same X-ray pump/X-ray probe method could find a broad range of applications, such as following the ultrafast structural changes that occur in light-sensitive molecules or the flow of energy in molecules. By understanding intramolecular energy flow, researchers can better develop novel materials to harness the sun’s energy, such as photovoltaics and photocatalysts.

    The new technique could also help researchers address challenges relating to the protein structure determination. For pharmaceutical studies, X-rays are often used to figure out the structures of proteins, but during that process they can also damage parts of them.

    “This technique lets you see how neighboring atoms are affected when certain regions interact with X-rays,” said Stephen Southworth, an Argonne senior X-ray scientist.

    By using an X-ray pump to excite one of the innermost electrons in the molecule, the researchers were able to target one of the electrons that is most central to and characteristic of the molecule. “This technique gives us the ability to take a series of quick snapshots to see what happens when we change a fundamental part of a molecule, and what we learn from it can inform how we approach the interactions between light and molecules in the future,” said Picon.

    The research, which was funded by the DOE Office of Science, involved a collaboration between Argonne, SLAC, and Kansas State University. “For these kinds of studies, you really need a team that combines world leaders in X-ray sources, particle detection and sample manipulation,” Southworth said.

    An article based on the study, Hetero-site-specific X-ray pump-probe spectroscopy for femtosecond intramolecular dynamics, appeared in the May 23 online edition of Nature Communications.

    See the full article here .

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    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. For more visit http://www.anl.gov.

    The Advanced Photon Source at Argonne National Laboratory is one of five national synchrotron radiation light sources supported by the U.S. Department of Energy’s Office of Science to carry out applied and basic research to understand, predict, and ultimately control matter and energy at the electronic, atomic, and molecular levels, provide the foundations for new energy technologies, and support DOE missions in energy, environment, and national security. To learn more about the Office of Science X-ray user facilities, visit http://science.energy.gov/user-facilities/basic-energy-sciences/.

    Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science

    Argonne Lab Campus

     
  • richardmitnick 3:29 pm on June 6, 2016 Permalink | Reply
    Tags: , Echo Technique Developed at SLAC Could Make X-ray Lasers More Stable, , X-ray Technology   

    From SLAC: “Echo Technique Developed at SLAC Could Make X-ray Lasers More Stable” 


    SLAC Lab

    June 6, 2016

    1
    A SLAC-led research team manipulated a beam of electrons (from top left to bottom right) with conventional laser light (red) in a way that could produce purer, more stable pulses in X-ray lasers. (SLAC National Accelerator Laboratory)

    Researchers from the Department of Energy’s SLAC National Accelerator Laboratory and Shanghai Jiao Tong University in China have developed a method that could open up new scientific avenues by making the light from powerful X-ray lasers much more stable and its color more pure.

    The idea behind the technique is to “seed” X-ray lasers with regular lasers, whose light already has these qualities.

    “X-ray lasers have very bright, very short pulses that are useful for all sorts of groundbreaking studies,” says SLAC accelerator physicist Erik Hemsing, the lead author of a study published today in Nature Photonics. “But the process that generates those X-rays also makes them ‘noisy’ – each pulse is a little bit different and contains a range of X-ray wavelengths, or colors – so they can’t be used for certain experiments. We’ve now demonstrated a technique that will allow the use of conventional lasers to make stable, single-wavelength X-rays that are exactly the same from one pulse to the next.”

    The method, called echo-enabled harmonic generation (EEHG), could enable new types of experiments, such as more detailed studies of electron motions in molecules.

    2
    Members of the EEHG team. From left: Bryant Garcia, Erik Hemsing, Gennady Stupakov, Tor Raubenheimer and Dao Xiang. (SLAC National Accelerator Laboratory)

    “We need better control over X-ray pulses for such experiments,” says Jerome Hastings, a researcher at SLAC’s Linac Coherent Light Source (LCLS) X-ray laser, who was not involved in the study. “The new study demonstrates that EEHG is a very promising method to get us there, and it could become a driver for science that can’t be done today.” LCLS is a DOE Office of Science User Facility.

    SLAC LCLS Inside
    SLAC LCLS Inside

    Planting Seeds of Stability with Conventional Lasers

    The process of generating X-ray laser pulses starts with accelerating bunches of electrons to high energies in linear particle accelerators. The speedy electrons then slalom through a special magnet known as an undulator, where they send out X-rays at every turn.

    Those X-rays, in turn, interact with the electron bunches, rearranging them into thin slices, or microbunches. The electrons in each microbunch collectively emit light that gets further amplified to produce extremely bright pulses of X-ray laser light.

    However, each microbunch of electrons radiates a little bit differently, resulting in X-ray pulses that contain spikes of several wavelengths with different intensities that vary from pulse to pulse. This “noise” poses challenges for applications that require identical X-ray pulses.

    “Optical and other conventional lasers, on the other hand, generate single-color light in a highly reproducible way,” says co-author Bryant Garcia, a graduate student in SLAC’s Accelerator Directorate. “If we could use their regular pulses as ‘seeds’ to form more regular microbunches in the electron beam, the X-ray laser pulses would also be much more uniform and stable.”

    4
    X-ray lasers amplify X-ray pulses (shown within the blue ovals) from electron beams (depicted as arrows) inside magnets known as undulators (left). Top: Each pulse normally contains a spectrum of X-ray colors and intensities that changes from pulse to pulse. Bottom: A technique known as echo-enabled harmonic generation (EEHG) could produce stable pulses containing a single X-ray color that vary very little from shot to shot. (SLAC National Accelerator Laboratory)

    Imprinting Echoes of Laser Light onto X-ray Pulses

    The problem is that wavelengths of conventional laser light are too long to directly seed the electron bunches. To get around that, researchers must shorten the wavelength by creating “harmonics” – light whose wavelength is a fraction of the original laser light.

    “Our study shows for the first time that we can generate the harmonics needed to slice electron bunches finely enough for X-ray laser applications,” Hemsing says.

    In their demonstration experiment at SLAC’s Next Linear Collider Test Accelerator (NLCTA), the researchers shone pairs of laser pulses on electron bunches passing through two magnetic stages, each composed of an undulator and other magnets.

    SLAC Next Linear Collider Test Accelerator (NLCTA)
    SLAC’s Next Linear Collider Test Accelerator (NLCTA)

    The first, optical-wavelength pulse left its “fingerprint” on the electron bunch, while the second, infrared pulse created an “echo” of the first that also contained harmonics.

    Together the laser pulses shuffled the electrons in the bunch so they formed microbunches in a very controlled and reproducible way – stable seeds that could be amplified to produce stable X-rays in future experiments.

    A Technique with Perspective for X-ray Lasers around the World

    The idea for the method was developed in 2009 by SLAC accelerator physicist Gennady Stupakov, one of the study’s co-authors. As a powerful new way of seeding future X-ray lasers, the concept immediately sparked excitement in the global research community. Since then, researchers have been trying to generate higher and higher harmonics, with the goal of reaching X-ray wavelengths of 10 nanometers or less.

    Proof-of-principle experiments at the NLCTA began in 2009 with the demonstration of the 3rd harmonic in 2010, 7th harmonic in 2012 and 15th harmonic in 2014.

    “We’ve now reached the infrared laser’s 75th harmonic, which allows us to produce microbunches able to generate light with a wavelength of 32 nanometers,” Bryant says. “This brings us for the first time within reach of our goal.”

    Although the method has yet to be implemented at an X-ray laser – the team is planning first X-ray EEHG experiments at the FERMI free-electron laser in Trieste, Italy – its benefits for light sources around the world are foreseeable.

    “Since EEHG produces microbunches by using well-defined laser pulses, all electrons emit light of the same color,” Hemsing says. “This has the potential to produce X-ray pulses that are 10 times sharper and brighter, and stable over time.”

    Researchers would also gain more control over X-ray laser pulses. For example, by changing the harmonic in the experiment, scientists could easily tune the color of the X-ray light.

    Other researchers involved in the study were SLAC’s Michael Dunning, Carsten Hast and Tor Raubenheimer, the principal investigator for the EEHG project, as well as Dao Xiang from Shanghai Jiao Tong University in China. The study is the culmination of the six-year program “Accelerator R&D for a Soft X-ray Free-Electron Laser: Echo-Enabled Harmonic Generation,” which was funded by the DOE Office of Science, Basic Energy Sciences. Additional funding sources were the DOE Office of Science, High Energy Physics; the Major State Basic Research Development Program, China; and the National Natural Science Foundation, China.

    4
    From left: Erik Hemsing, Gennady Stupakov and Bryant Garcia at the EEHG demonstration experiment at SLAC’s Next Linear Collider Test Accelerator (NLCTA). (SLAC National Accelerator Laboratory)

    See the full article here .

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  • richardmitnick 12:36 pm on May 23, 2016 Permalink | Reply
    Tags: , , , X-ray Technology   

    From SLAC: “Caught on Camera: First Movies of Droplets Getting Blown Up by X-ray Laser” 


    SLAC Lab

    May 23, 2016

    Details Revealed in SLAC Footage Will Give Researchers More Control in X-ray Laser Experiments

    Researchers have made the first microscopic movies of liquids getting vaporized by the world’s brightest X-ray laser at the Department of Energy’s SLAC National Accelerator Laboratory. The new data could lead to better and novel experiments at X-ray lasers, whose extremely bright, fast flashes of light take atomic-level snapshots of some of nature’s speediest processes.

    “Understanding the dynamics of these explosions will allow us to avoid their unwanted effects on samples,” says Claudiu Stan of Stanford PULSE Institute, a joint institute of Stanford University and SLAC. “It could also help us find new ways of using explosions caused by X-rays to trigger changes in samples and study matter under extreme conditions. These studies could help us better understand a wide range of phenomena in X-ray science and other applications.”


    Researchers have recorded the first movies of liquids getting vaporized by SLAC’s Linac Coherent Light Source (LCLS), the world’s brightest X-ray laser. The movies reveal new details that could lead to better and novel experiments at X-ray lasers. (SLAC National Accelerator Laboratory)
    Access mp4 video here .

    Liquids are a common way of bringing samples into the path of the X-ray beam for analysis at SLAC’s Linac Coherent Light Source (LCLS), a DOE Office of Science User Facility, and other X-ray lasers. At full power, ultrabright X-rays can blow up samples within a tiny fraction of a second. Fortunately, in most cases researchers can take the data they need before the damage sets in.


    Access the mp4 video here .

    The new study, published* today in Nature Physics, shows in microscopic detail how the explosive interaction unfolds and provides clues as to how it could affect X-ray laser experiments.

    Stan and his team looked at two ways of injecting liquid into the path of the X-ray laser: as a series of individual drops or as a continuous jet. For each X-ray pulse hitting the liquid, the team took one image, timed from five billionths of a second to one ten-thousandth of a second after the pulse. They strung hundreds of these snapshots together into movies.

    “Thanks to a special imaging system developed for this purpose, we were able to record these movies for the first time,” says co-author Sébastien Boutet from LCLS. “We used an ultrafast optical laser like a strobe light to illuminate the explosion, and made images with a high-resolution microscope that is suitable for use in the vacuum chamber where the X-rays hit the samples.”

    The footage shows how an X-ray pulse rips a drop of liquid apart. This generates a cloud of smaller particles and vapor that expands toward neighboring drops and damages them. These damaged drops then start moving toward the next-nearest drops and merge with them.


    This movie shows how a drop of liquid explodes after being struck by a powerful X-ray pulse from LCLS. The vertical white line at the center shows the position of the X-ray beam. The movie captures the first 9 millionths of a second after the explosion. (SLAC National Accelerator Laboratory)
    Access mp4 video here .

    In the case of jets, the movies show how the X-ray pulse initially punches a hole into the stream of liquid. This gap continues to grow, with the ends of the jet on either side of the gap beginning to form a thin liquid film. The film develops an umbrella-like shape, which eventually folds back and merges with the jet.


    Researchers studied the explosive interaction of X-ray pulses from LCLS with liquid jets, as shown in this movie of the first 9 millionths of a second after the explosion. (SLAC National Accelerator Laboratory)
    Access mp4 video here .

    Based on their data, the researchers were able to develop mathematical models that accurately describe the explosive behavior for a number of factors that researchers vary from one LCLS experiment to another, including pulse energy, drop size and jet diameter.

    They were also able to predict how gap formation in jets could pose a challenge in experiments at the future light sources European XFEL in Germany and LCLS-II, under construction at SLAC. Both are next-generation X-ray lasers that will fire thousands of times faster than current facilities.

    European XFEL Test module
    European XFEL Test module

    SLAC LCLS-II line
    SLAC LCLS-II line

    “The jets in our study took up to several millionths of a second to recover from each explosion, so if X-ray pulses come in faster than that, we may not be able to make use of every single pulse for an experiment,” Stan says. “Fortunately, our data show that we can already tune the most commonly used jets in a way that they recover quickly, and there are ways to make them recover even faster. This will allow us to make use of LCLS-II’s full potential.”

    The movies also show for the first time how an X-ray blast creates shock waves that rapidly travel through the liquid jet. The team is hopeful that these data could benefit novel experiments, in which shock waves from one X-ray pulse trigger changes in a sample that are probed by a subsequent X-ray pulse. This would open up new avenues for studies of changes in matter that occur at time scales shorter than currently accessible.

    Other institutions involved in the study were Max Planck Institute for Medical Research, Germany; Princeton University; and Paul Scherrer Institute, Switzerland. Funding was received from the DOE Office of Science; Max Planck Society; Human Frontiers Science Project; and SLAC’s Laboratory Directed Research & Development program.

    *Science paper:
    Liquid explosions induced by X-ray laser pulses

    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 7:27 am on May 10, 2016 Permalink | Reply
    Tags: , , RIKEN SACLA, , X-ray Technology   

    From BNL: “Ultra-fast X-ray Lasers Illuminate Elusive Atomic Spins” 

    Brookhaven Lab

    May 9, 2016
    Justin Eure
    (631) 344-2347
    jeure@bnl.gov

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

    New x-ray technique reveals never-before-seen, trillionth-of-a-second magnetic fluctuations that transform the electronic and magnetic properties of materials.

    1
    Brookhaven Lab physicists Pavol Juhas, John Hill, Mark Dean, Yue Cao, and Vivek Thampy, all of the Condensed Matter Physics and Materials Science Department, except Hill, who is director of NSLS-II.

    A quick flash of light can make ordinary materials extraordinary, potentially inducing qualities such as the perfect efficiency of superconductivity even at room temperature. But these subatomic transformations are infamously fleeting—they vanish in just trillionths of a second.

    Now, an international team of scientists has used synchronized infrared and x-ray laser pulses to simultaneously manipulate and reveal the ultra-fast magnetic properties of this promising quantum landscape. The rapid, light-driven switching between magnetic states, explored here with unprecedented precision, could one day revolutionize the reading and writing of data in computers and other digital devices.

    The study, published* May 9, 2016, in the journal Nature Materials, was led by scientists at the U.S. Department of Energy’s Brookhaven National Laboratory and included researchers from the U.S., China, Germany, Japan, Spain, and the UK.

    “We developed a way to reveal light-induced femtosecond magnetic dynamics in as yet unseen detail,” said Mark Dean, a physicist at Brookhaven Lab and lead author on the study. “This brings us closer to perfecting a recipe for manipulating these materials on ultra-fast time scales.”

    This novel x-ray technique, called time-resolved resonant inelastic scattering, revealed the subtle spin correlations, which travel as waves through the material and define its magnetic properties. Crucially, they behaved differently between two- and three-dimensional spaces when sparked by an infrared laser pulse.

    “Within a two-dimensional atomic plane, the novel state lasted just a few picoseconds,” said Brookhaven physicist and study coauthor Yue Cao. “But three-dimensional correlations also cross between planes, and these took hundreds of picoseconds to vanish—on this scale, that difference is tremendous. It is enormously exciting to help pioneer a new technique and see it succeed.”

    The bulk of the experimental work relied on the powerful and precise x-ray lasers available at SLAC National Accelerator Laboratory’s Linac Coherent Light Source, a DOE Office of Science User Facility, and the SACLA facility in Japan.

    SLAC/LCLS
    SLAC/LCLS

    SACLA Free-Electron Laser Riken Japan
    SACLA Free-Electron Laser Riken Japan

    Doping with light

    To introduce novel magnetic and electronic qualities, scientists often use a technique called chemical doping to augment the atomic configuration of a material. Electrons can be meticulously added or removed, but the process is permanent.

    “We wanted to access similar states transiently, so we used photo-doping,” Dean said. “A laser pulse supplies the needed photons, which changes the electron and spin configuration in the sample—the same spins thought to be responsible for phenomena like superconductivity. Moments later, the material returns to its native state.”

    In this work, the scientists used a strontium-iridium-oxygen compound (Sr2IrO4), selected for its strong magnetic interactions. Manipulating spin in the material was relatively easy—the real challenge was catching it in motion.

    Bright, fast flashes

    The collaboration turned to two powerful photon sources: the LCLS and SACLA, both uniquely capable of illuminating a quantum spin wave mid-stride. Both facilities can produce x-ray pulses with extremely short duration and high brightness.

    “Knowing that these facilities could produce fast and accurate enough laser pulses inspired this entire collaboration,” said study coauthor John Hill, the director of Brookhaven Lab’s National Synchrotron Light Source II, another DOE Office of Science User Facility.

    BNL NSLS-II Interior
    BNL NSLS-II

    For the experiment, an initial infrared laser pulse struck the layered Sr2IrO4 compound, destroying the native magnetic state. For a brief moment, the electrons inside the material formed spin waves that rippled through the material and radically changed its electronic and magnetic properties. Trillionths of a second later, an x-ray pulse followed and bounced off those emergent waves. By measuring the change in both momentum and the angles of diffraction, the scientists could deduce the transient electronic and magnetic qualities.

    This specific process of bouncing and tracking x-rays, called resonant inelastic x-ray scattering (RIXS), was also pioneered by members of this collaboration to explore similar phenomena in condensed matter systems. The new research builds on that to include time-resolved data points.

    “Beyond the remarkable capabilities of LCLS and SACLA to supply ultra-short femtosecond x-ray pulses, the challenge we were facing was how to detect the response of the spins,” said study coauthor Xuerong Liu from the Institute of Physics in Beijing. “That is, we needed a specialized x-ray detection system or ‘camera.'”

    The scientists developed a highly specialized RIXS spectrometer, which used millimeter-sized silicon crystals to measure the exact energy of the rebounding x-rays.

    The data revealed a clear difference in the propagation and timescale of the magnetic phenomena, with the inter-layer correlations taking hundreds of times longer to recover than those within each layer.

    “The findings match theoretical expectations, which is encouraging, but more importantly they demonstrate the strength and precision of this technique,” said collaborator Michael Först of the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg, Germany. “We can now dive deeper into the mechanism and think of strategies to fine-tune the control of magnetic properties with light.”

    Next, the scientists plan to explore optical pulses at even longer wavelengths, which will shift atoms within the material without directly exciting the electrons and spins. That work may help reveal the native magnetic coupling within the material, which in turn will clarify how to best break that coupling and toggle between different electronic and magnetic states.

    The research was funded in part by the DOE’s Office Science (BES), which supported experimentation at LCLS.

    *Science paper:
    Ultrafast energy- and momentum-resolved dynamics of magnetic correlations in the photo-doped Mott insulator Sr2IrO4

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition
    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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  • richardmitnick 10:09 am on May 6, 2016 Permalink | Reply
    Tags: , , Supercooled Cavities for Particle Acceleration, X-ray Technology   

    From BNL: “Supercooled Cavities for Particle Acceleration” 

    Brookhaven Lab

    May 3, 2016
    Ariana Tantillo

    Very low temperatures support research at Brookhaven National Laboratory’s National Synchrotron Light Source II

    BNL NSLS-II Building
    BNL NSLS-II Building

    BNL NSLS-II Interior
    BNL NSLS-II Interior

    1
    A superconducting radio-frequency cryomodule installed in the NSLS-II ring. No image credit.

    When you think about the coldest places on Earth, the National Synchrotron Light Source II (NSLS-II), a U.S. Department of Energy (DOE) Office of Science User Facility located at the DOE’s Brookhaven National Laboratory, probably doesn’t come to mind. But accelerating electrons around the half-mile-long ring of NSLS-II at nearly the speed of light requires some extremely cold temperatures, hundreds of degrees below the freezing point of water.

    Supercool temperatures mean super cool science research can go on.

    A continuous flow of electrons

    As electrons circle around NSLS-II’s ring, they emit extremely bright X-rays that scientists use to image materials, such as soil samples, batteries, and biological proteins. “The images are not necessarily photographs, but spectrum, absorption lines, or diffraction patterns,” explained James Rose, head of the Radio Frequency Systems Group for NSLS-II.

    By studying the fluorescence, diffraction, scattering, and absorption of X-rays, scientists can uncover a material’s atomic structure, which gives rise to its chemical, electronic, and structural properties. From examining soil samples to understand the uptake of chemical runoff, to watching in real time as batteries operate to discover where and how materials inside break down, to examining the structure of biological proteins to help design new drugs for treating disease, scientists at NSLS-II probe the inner workings of various kinds of materials.

    In producing these X-rays, the electrons lose energy and slow down. For the electrons to continue generating the high-power X-ray beams used by scientists from around the world to image materials, this energy must be replenished.

    At NSLS-II, electrons gain this energy by passing through two hollow metal (niobium) chambers called radio-frequency (RF) cavities that contain an electromagnetic field. The electric field transfers energy to the electrons, propagating them along the ring. “An RF cavity is a resonator like an organ pipe or guitar string,” said Rose. “Our cavities are tuned to a particular frequency such that an electron traveling around the ring passes through the cavity at the same phase each trip, and gains the same energy per pass as it loses energy to synchrotron radiation, or light. Giving energy to the electron at just the right time increases its energy, much like someone pushing a child on a swing.”

    When cooled to an extremely low, or cryogenic, temperature, the niobium in the RF cavity becomes superconducting—that is, it loses nearly all resistance to an electric current. As a result, electrons can flow freely through the cavities. If niobium were conducting electricity as it would at room temperature, there would be a large resistance to the flow of electrons. When electron flow is resisted, the electrical energy that moves the electrons is converted into heat energy—a waste product. Without this resistance, electricity can be delivered to the cavity much more efficiently.

    “If the cavities were not superconducting, almost seven times more energy would be required to keep the electrons flowing to produce high-intensity X-ray beams,” said Rose.

    The superconductivity not only reduces energy loss in the cavities but it also provides for electron beam stability.

    “Because we don’t need to worry about keeping resistive losses low, we can design the cavities with a large aperture that allows resonant frequencies above the cavity’s tuned frequency to leak out of the cavity into absorbers that damp, or reduce the amplitude of, the higher-frequency oscillations. If these higher frequencies were not damped, they would add and subtract energy from the beam out of sequence. That’s like pushing the child on the swing randomly, causing the swing to slow down or stopping the child short at the highest speed,” explained Rose.

    Supercooled cavities

    At NSLS-II, the RF cavities are continuously immersed in liquid helium, which, with the help of liquid nitrogen, cools niobium to its superconducting state. The cavities are installed within cryomodules, which are essentially vacuum-insulated containers like thermos bottles that maintain the ultra-cold temperatures of the liquid helium to allow for near-zero electrical resistance within the RF cavity.

    2
    Brookhaven Lab staff members (left to right) James Rose, John Gosman, and William Gash with one of the two electron bunch–lengthening radio-frequency cavities that will be installed at the National Synchrotron Light Source II (NSLS-II). By reducing the number and intensity of collisions between electrons circling the NSLS-II electron storage ring, these cavities will help prevent electron beam loss and thus extend the lifetime of the beams used to conduct experiments.

    “The only way to make liquid helium from gaseous helium is to cool it down,” explained Rose. “Because nitrogen is inexpensive as compared to helium, we use liquid nitrogen to precool the helium from room temperature down to liquid nitrogen’s boiling point of 321 degrees below zero. From there, we cool the helium down to approximately minus 450 degrees Fahrenheit.”

    Cooling helium gas into a liquid is a multistep process. First, the gas is squeezed in compressors. As the gas molecules are forced into a smaller volume, the pressure and temperature of the gas rise. The gas is then fed into an insulated enclosure called a cold box, where three fast-moving expansion turbines liquefy the gas by reducing its pressure, causing the gas molecules to spread apart. This rapid expansion causes the gas to cool and a portion of it to liquefy.

    “The cold box is the heart of the cryogenic plant,” said William Gash, a cryogenics engineer in Brookhaven’s Utilities Group. “Its turbines rotate at many thousands of revolutions per second, as compared to a car, which operates in revolutions per minute.”

    Once liquefied, the helium is stored in a large vacuum-insulated container and distributed through insulated piping and control valves directly into the cryomodules to surround the RF cavities.

    The remaining cooled gas is returned to the cold box, where it flows through heat exchangers to precool the incoming high-pressure gas before being sent to the compressor to start the cycle again.

    “The cryogenics plant is a closed-loop system,” explained Gash. “All of the helium is recovered. Even in the event of an emergency, we have a recovery system in place to ensure the supply is retrieved.”

    Longer-lived beams

    In the next five years or so, additional superconducting RF cavities and valves will be installed.

    “This installation will provide the RF power needed to support more beams and thus more experiments at NSLS-II,” said Rose.

    Two of the cavities will be electron bunch–lengthening cavities, which “lengthen” the bunches, or groups, of electrons traveling around the ring.

    In dense bunches, electrons circling the ring undergo collisions with other electrons in the bunch. “Imagine dancers that bump into one another on a crowded dance floor,” said Rose.

    These collisions scatter the electrons, causing some electrons to be ejected from the bunch. Eventually, these ejected electrons hit the beam pipe and lose their energy to radiation. “Some dancers leave the dance floor and go home,” said Rose. “By lengthening the electron bunches (increasing the size of the dance floor), we can reduce the density of electrons (spreading people out on the dance floor), thereby reducing the number and intensity of the collisions. Ultimately, these new cavities will extend the lifetime of the beams.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

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    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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  • richardmitnick 8:38 am on May 6, 2016 Permalink | Reply
    Tags: , , , X-ray Technology   

    From DESY: “High-speed camera snaps biosensor’s rapid reaction to light” 

    DESY
    DESY

    X-ray study reveals ultrafast dynamics of photoactive yellow protein

    1
    Inner structure of the photactive yellow protein 800 femtoseconds after the trans-to-cis isomerisation has been initiated by an ultrafast blue laser. The chromophore binding pocket is cut open and the chromophore itself is highlighted by the bulls eye. Credit: Marius Schmidt/University of Wisconsin-Milwaukee

    Using a high-speed X-ray camera, an international team of scientist including researchers from DESY has revealed the ultrafast response of a biosensor to light. The study, published* in the US journal Science, shows light-driven atomic motions lasting just 100 quadrillionths of a second (100 femtoseconds). The technique promises insights into the ultrafast dynamics of various light sensitive biomolecules responsible for important biological processes like photosynthesis or vision.

    The team lead by Marius Schmidt from the University of Wisconsin, Milwaukee used the LCLS X-ray laser at SLAC National Accelerator Laboratory in the U.S. to look at the light-sensitive part of a protein called photoactive yellow protein, or PYP.

    SLAC/LCLS
    SLAC/LCLS

    It functions as an “eye” in purple bacteria, helping them sense blue light and stay away from light that is too energetic and potentially harmful.

    For their investigation, the scientists sent a stream of tiny PYP crystals into a sample chamber. There, each crystal was struck by a flash of optical laser light and then, almost immediately after, an X-ray pulse was used to interrogate the protein’s structural response to the light at the atomic level. The structure is determined indirectly from the intricate pattern of X-ray light scattered from the crystal. By varying the time between the two pulses, scientists were able to see how the protein morphed over time. “By placing the various obtained molecular structures in order of the time delay between the optical and X-ray flashes we obtain a molecular movie of the reaction as it evolves from the first step at 100 femtoseconds to several thousand femtoseconds,” explained the first author of the paper, Kanupriya Pande, also from the University of Wisconsin and now at the Center for Free-Electron Laser Science CFEL at DESY.

    “The absorption of light leaves PYP in an excited state from which it relaxes very quickly,” explained Schmidt, the study’s principal investigator. “It does so by rearranging its atomic structure in what is known as trans-to-cis isomerisation. We’re the first to succeed in taking real-time snapshots of this type of reaction.” This type of isomerisation is also what gives vision – in that case the retinal chromophore undergoes a cis-to-trans isomerisation that ultimately leads to neuronal excitation in the eye.

    “We were able to obtain detailed structures at incredibly short time points after the initial absorption event by taking flash X-ray snapshots with the world’s brightest X-ray source,” said co-author Henry Chapman from CFEL at DESY. But, as Pande pointed out, “these are very challenging experiments, where we needed considerable innovation to assign the correct time stamps to hundreds of thousands of X-ray patterns.”

    The researchers had already studied light-induced structural changes in PYP at LCLS before, revealing atomic motions as fast as 10 billionths of a second (10 nanoseconds). By tweaking their experiment with a faster optical laser and better timing tools and sorting, they were now able to improve their speed limit 100,000 times and capture reactions in the protein that are 1,000 times faster than any seen in an X-ray experiment before.

    “The new data show for the first time how the bacterial sensor reacts immediately after it absorbs light,” says co-author Andy Aquila from SLAC. “The initial response, which is almost instantaneous, is absolutely crucial because it creates a ripple effect in the protein, setting the stage for its biological function.”

    The technique could prove valuable to unveil a number of other important ultrafast light-driven processes, for instance how visual pigments in the human eye respond to light, and how absorbing too much of it damages them; how photosynthetic organisms turn light into chemical energy, a process that could serve as a model for the development of new energy technologies; or how atomic structures respond to light pulses of different shape and duration, an important first step toward controlling chemical reactions with light.

    Together with the University of Wisconsin, Milwaukee, SLAC and DESY, the following institutions were involved in this study: Imperial College London, the University of Jyväskylä in Finland, Arizona State University, Max Planck Institute for Structure and Dynamics of Matter in Hamburg, State University of New York at Buffalo, University of Chicago, Lawrence Livermore National Laboratory and University of Hamburg.

    *Science paper:
    Femtosecond structural dynamics drives the trans/cis isomerization in photoactive yellow protein

    See the full article here .

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    desi

    DESY is one of the world’s leading accelerator centres. Researchers use the large-scale facilities at DESY to explore the microcosm in all its variety – from the interactions of tiny elementary particles and the behaviour of new types of nanomaterials to biomolecular processes that are essential to life. The accelerators and detectors that DESY develops and builds are unique research tools. The facilities generate the world’s most intense X-ray light, accelerate particles to record energies and open completely new windows onto the universe. 
That makes DESY not only a magnet for more than 3000 guest researchers from over 40 countries every year, but also a coveted partner for national and international cooperations. Committed young researchers find an exciting interdisciplinary setting at DESY. The research centre offers specialized training for a large number of professions. DESY cooperates with industry and business to promote new technologies that will benefit society and encourage innovations. This also benefits the metropolitan regions of the two DESY locations, Hamburg and Zeuthen near Berlin.

     
  • richardmitnick 8:31 am on May 3, 2016 Permalink | Reply
    Tags: , , X-ray Technology   

    From XFEL: “World’s most precise mirror arrives in Hamburg” 

    XFEL bloc

    European XFEL

    03 May 2016

    The first of several ultraflat mirrors is a milestone of a rigorous research and development effort.

    A 95-cm long mirror that is more precise than any other yet built was delivered to European XFEL, an X-ray laser research facility that is under construction in the Hamburg area of Germany. The mirror is superflat and does not deviate from its surface quality by more than one nanometre, or a billionth of a metre. It is the first of several of its kind needed for the European XFEL. Each will be essential to the facility’s operation, enabling scientists from around the globe to reliably use the world’s brightest X-ray laser light for research into ultrafast chemical processes, complex molecular structures, and extreme states of matter. The precision of the European XFEL mirror is equivalent to a 40-km long road not having any bumps larger than the width of a hair. The mirror’s production is the culmination of a long research and development process involving several institutes and companies in Japan, France, Italy, and Germany.

    The mirror body, with a 95 cm long and 5.2 cm wide reflective face, is made from a single crystal of silicon that was crafted by industrial partners in France and Italy. In order to polish a mirror of the required length to European XFEL’s nanometre specification, the optics company JTEC in Osaka, Japan, used a new polishing method using a pressurized fluid bath capable of stripping atom-thick layers off of the crystal. This development required the construction of a brand-new facility that would be able to meet the exceptional demands from the European XFEL, while also expanding the company’s ability to serve other, similar facilities, such as the LCLS in the U.S. and SwissFEL in Switzerland.

    SLAC/LCLS
    SLAC/LCLS

    SwissFEL Paul Sherrer Institute
    SwissFEL Paul Sherrer Institute

    The polishing technique alone took nearly a year to develop to a point where the extreme quality could be reached.

    1
    European XFEL scientist Maurizio Vannoni inspects the delivered superflat mirror, which does not deviate from a perfect surface by more than a billionth of a metre. European XFEL

    “When we first started working on these optics, we were looking for something that simply didn’t exist at anywhere near this precision”, says Harald Sinn, who leads the European XFEL X-Ray Optics group. “Now we have the first ever mirror at this extreme specification.”

    The mirrors have to be so precise because of the laser properties of the X-rays at the European XFEL. These properties are essential to clearly image matter at the atomic level. Previously, European XFEL simulations had shown that any distortions in the mirrors greater than one nanometre would cause the properties of the laser spot on the sample to be degraded.

    Mirrors of this series will be used to deflect the X-rays by up to a few tenths of a degree into the European XFEL’s six scientific instruments in its underground experiment hall in the town of Schenefeld. This is done because the instruments, which are parallel to each other, will eventually be able to operate in parallel, enabling scientists to have greater access to the facility and its unique X-ray light. Additionally, similar mirrors will focus the X-ray light within some of the facility’s instruments.

    However, the particular mirror that was delivered is needed for filtering the light generated by the facility to only the kind needed for experiments. Within the European XFEL’s X-ray laser light-generating structures, called undulators, some undesirable wavelengths of light are produced. A set of these superflat mirrors will be arranged after each undulator in the facility’s underground tunnels, and the position of each mirror allows for only the desired wavelength of laser light to continue towards the experiment hall. The undesirable wavelengths of light are more energetic and pass through the mirror instead of reflecting, ending up in an adjacent absorber made of boron carbide and tungsten.

    The mirror will now be measured at European XFEL and Helmholtz Zentrum Berlin for additional verification of its specifications. Three more mirrors of the same type are due to arrive at European XFEL in May.

    See the full article here .

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    XFEL Campus

    The Hamburg area will soon boast a research facility of superlatives: The European XFEL will generate ultrashort X-ray flashes—27 000 times per second and with a brilliance that is a billion times higher than that of the best conventional X-ray radiation sources.

    The outstanding characteristics of the facility are unique worldwide. Starting in 2017, it will open up completely new research opportunities for scientists and industrial users.

     
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