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  • richardmitnick 9:03 am on October 14, 2016 Permalink | Reply
    Tags: Crystal Clear Imaging: Infrared Brings to Light Nanoscale Molecular Arrangement, CU Boulder STROBE for Science and Technology Center on Real-Time Functional Imaging, Infrared imaging, , , Scattering-type scanning near-field optical microscopy, X-ray Technology   

    From LBNL- “Crystal Clear Imaging: Infrared Brings to Light Nanoscale Molecular Arrangement” 

    Berkeley Logo

    Berkeley Lab

    October 13, 2016
    Glenn Roberts Jr.

    Infrared light (pink) produced by Berkeley Lab’s Advanced Light Source synchrotron (upper left) and a conventional laser (middle left) is combined and focused on the tip of an atomic force microscope (gray, lower right), where it is used to measure nanoscale details in a crystal sample (dark red). (Credit: Berkeley Lab, CU-Boulder)

    Detailing the molecular makeup of materials—from solar cells to organic light-emitting diodes (LEDs) and transistors, and medically important proteins—is not always a crystal-clear process.

    To understand how materials work at these microscopic scales, and to better design materials to improve their function, it is necessary to not only know all about their composition but also their molecular arrangement and microscopic imperfections.

    Now, a team of researchers working at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) has demonstrated infrared imaging of an organic semiconductor known for its electronics capabilities, revealing key nanoscale details about the nature of its crystal shapes and orientations, and defects that also affect its performance.

    To achieve this imaging breakthrough, researchers from Berkeley Lab’s Advanced Light Source (ALS) and the University of Colorado-Boulder (CU-Boulder) combined the power of infrared light from the ALS and infrared light from a laser with a tool known as an atomic force microscope.

    LBNL Advanced Light Source
    LBNL Advanced Light Source

    The ALS, a synchrotron, produces light in a range of wavelengths or “colors”—from infrared to X-rays—by accelerating electron beams near the speed of light around bends.

    The researchers focused both sources of infrared light onto the tip of the atomic force microscope, which works a bit like a record-player needle—it moves across the surface of a material and measures the subtlest of surface features as it lifts and dips.

    The technique, detailed in a recent edition of the journal Science Advances, allows researchers to tune the infrared light in on specific chemical bonds and their arrangement in a sample, show detailed crystal features, and explore the nanoscale chemical environment in samples.

    This image shows the crystal shape and height of a material known as PTCDA, with height represented by the shading (white is taller, darker orange is lowest). The scale bar represents 500 nanometers. The illustration at bottom is a representation of the crystal shape. (Credit: Berkeley Lab, CU-Boulder)

    “Our technique is broadly applicable,” said Hans Bechtel an ALS scientist. “You could use this for many types of material—the only limitation is that it has to be relatively flat” so that the tip of the atomic force microscope can move across its peaks and valleys.

    Markus Raschke, a CU-Boulder professor who developed the imaging technique with Eric Muller, a postdoctoral researcher in his group, said, “If you know the molecular composition and orientation in these organic materials then you can optimize their properties in a much more straightforward way.

    “This work is informing materials design. The sensitivity of this technique is going from an average of millions of molecules to a few hundred, and the imaging resolution is going from the micron scale (millionths of an inch) to the nanoscale (billionths of an inch),” he said.

    The infrared light of the synchrotron provided the essential wide band of the infrared spectrum, which makes it sensitive to many different chemicals’ bonds at the same time and also provides the sample’s molecular orientation. The conventional infrared laser, with its high power yet narrow range of infrared light, meanwhile, allowed researchers to zoom in on specific bonds to obtain very detailed imaging.

    “Neither the ALS synchrotron nor the laser alone would have given us this level of microscopic insight,” Raschke said, while the combination of the two provided a powerful probe “greater than the sum of its parts.”

    Raschke a decade ago first explored synchrotron-based infrared nano-spectroscopy using the BESSY synchrotron in Berlin. With his help and that of ALS scientists Michael Martin and Bechtel, the ALS in 2014 became the first synchrotron to offer nanoscale infrared imaging to visiting scientists.

    The technique is particularly useful for the study and understanding of so-called “functional materials” that possess special photonic, electronic, or energy-conversion or energy-storage properties, he noted.

    In principle, he added, the new advance in determining molecular orientation could be adapted to biological studies of proteins. “Molecular orientation is critical in determining biological function,” Raschke said. The orientation of molecules determines how energy and charge flows across from cell membranes to molecular solar energy conversion materials.

    Bechtel said the infrared technique permits imaging resolution down to about 10-20 nanometers, which can resolve features up to 50,000 times smaller than a grain of sand.

    The imaging technique used in these experiments, known as “scattering-type scanning near-field optical microscopy,” or s-SNOM, essentially uses the atomic force microscope tip as an ultrasensitive antenna, which transmits and receives focused infrared light in the region of the tip. Scattered light, captured from the tip as it moves over the sample, is recorded by a detector to produce high-resolution images.

    “It’s non-invasive, and it provides information about molecular vibrations,” as the microscope’s tip moves over the sample, Bechtel said. Researchers used the technique to study the crystalline features of an organic semiconductor material known as PTCDA (perylenetetracarboxylic dianhydride).

    Researchers reported that they observed defects in the orientation of the material’s crystal structure that provide a new understanding of the crystals’ growth mechanism and could aid in the design molecular devices using this material.

    Researchers measured the molecular orientation of crystals (light gray and white) in samples of a semiconductor material known as PTCDA. The scale bar is 500 nanometers. The colored dots correspond to the orientation of the crystals in the color bar to the left. The figures at far left show the tip of the atomic force microscope in relation to different crystal orientations. (Credit: Berkeley Lab, CU-Boulder)

    The new imaging capability sets the stage for a new National Science Foundation Center, announced in late September, that links CU-Boulder with Berkeley Lab, UC Berkeley, Florida International University, UC Irvine, and Fort Lewis College in Durango, Colo. The center will combine a range of microscopic imaging methods, including those that use electrons, X-rays, and light, across a broad range of disciplines.

    This center, dubbed STROBE for Science and Technology Center on Real-Time Functional Imaging, will be led by Margaret Murnane, a distinguished professor at CU-Boulder, with Raschke serving as a co-lead.

    At Berkeley Lab, STROBE will be served by a range of ALS capabilities, including the infrared beamlines managed by Bechtel and Martin and a new beamline dubbed COSMIC (for “coherent scattering and microscopy”). It will also benefit from Berkeley Lab-developed data analysis tools.

    Other contributors to the work include Benjamin Pollard and Peter van Blerkom, both members of Raschke’s group at CU-Boulder.

    The work was supported by the National Science Foundation. The ALS is a DOE Office of Science User Facility.

    See the full article here .

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  • richardmitnick 12:46 pm on October 3, 2016 Permalink | Reply
    Tags: ALS-U, , , , X-ray Technology   

    From LBNL: “Transformational X-ray Project Takes a Step Forward” 

    Berkeley Logo

    Berkeley Lab

    October 3, 2016
    Glenn Roberts Jr.

    A time-lapse view of the Advanced Light Source building at night. (Credit: Haris Mahic/Berkeley Lab)

    The U.S. Department of Energy (DOE) has confirmed the need for a unique source of X-ray light that would produce beams up to 1,000 times brighter than are now possible at Lawrence Berkeley National Laboratory’s (Berkeley Lab) Advanced Light Source (ALS), enabling new explorations of chemical reactions, battery performance, biological processes and exotic materials.


    The proposed Advanced Light Source Upgrade project, also known as ALS-U, has cleared the first step in the DOE approval process. On Sept. 27 it received “critical decision zero,” also known as CD-0, which approves the scientific need for the project. This initial step sets in motion a process of additional planning and reviews, and the laboratory will begin the upgrade’s conceptual design.

    This rendering shows the existing equipment at Berkeley Lab’s Advanced Light Source (lower right) that forms the storage ring where accelerated electrons give off energy in the form of light. A planned upgrade, ALS-U (left and upper right), would replace this storage ring with a denser array of magnets, known as an MBA lattice, that would produce far brighter, steadier beams of so-called “soft” X-ray light. A unique secondary ring along the ALS’s inner wall, called an “accumulator” ring, would rapidly replenish the energy in the main ring. (Credit: Berkeley Lab)

    If ultimately advanced, the ALS-U would feature a new, circular array of powerful, compact magnets. This state-of-the-art array, known as a “multibend achromat (MBA) lattice,” and other improvements would allow the ALS to achieve far brighter, steadier beams of so-called “soft” or low-energy X-ray light to probe matter with unprecedented detail.

    MBA systems have been demonstrated successfully at a light source in Sweden known as MAX IV, and will be put to use in a planned upgrade to Argonne National Laboratory’s Advanced Photon Source [AS]facility in Illinois that specializes in a range of energies known as “hard” X-ray light that is complementary to the separate range of X-ray energies produced at the ALS.

    MAX IV Lund, Sweden
    MAX IV Lund, Sweden

    ANL APS interior

    “This upgrade project is a very high priority for the laboratory and builds upon the lab’s long legacy of building and operating particle accelerators,” said Berkeley Lab Director Michael Witherell. “The ALS-U project will benefit from our expertise in many disciplines here, from engineering to accelerator and beam physics, and computer modeling and simulation.”

    Dave Robin, who is leading the ALS-U effort, said, “We’re excited by this development. ALS-U is designed to be the world’s brightest soft X-ray synchrotron light source. It will enable a generational leap, surpassing any soft X-ray storage-ring-based light source operating, under construction, or planned.”

    The electron beam profile of Berkeley Lab’s Advanced Light Source today (left), compared to the brighter, highly focused beam (right) that is possible with an upgrade known as ALS-U. (Credit: Berkeley Lab).

    The present-day ALS is already a premier destination for thousands of scientists from around the nation and world each year to conduct soft X-ray experiments. Soft X-rays are particularly suited to studies of chemical, electronic, and magnetic properties of materials. The upgrade would deliver light to experiments in nearly continuous waves that are more uniform, or highly “coherent” and laser-like, which would allow scientists to resolve nanoscale properties in a range of samples and to observe real-time chemical processes and material functions.

    “ALS now is the world leader in science that utilizes soft X-rays. ALS-U will allow us to continue to lead the world in measuring and understanding new materials and chemical systems for the 21st century,” said Roger Falcone, ALS director. “With this brighter source, we can move from where we take high-resolution static images to making movies. We can look at things in finer detail and see how they are functioning in real time.”

    The MERLIN X-ray beamline at Berkeley Lab’s Advanced Light Source, pictured here, specializes in studies of electronic structure in materials with exotic electronic and magnetic properties. (Credit: Roy Kaltschmidt/Berkeley Lab)

    In particular, the brighter, more coherent beams, which would approach the fundamental limits in performance for soft X-rays, will be useful for exploring materials at the nanoscale to map out their physical, chemical, and electronic structure as they evolve. Modern materials are complex and inherently varied, so their functionality can only be understood by measuring this non-uniformity in their properties.

    Scientists could use these beams to produce 3-D maps of battery and fuel cell chemistry at work, for example, which could ultimately provide clues to improving their performance.

    The brighter, more coherent, beams could also be used to explore exotic materials phenomena like superconductivity, in which materials can carry electrical current with nearly zero loss; and to study unusual quantum properties that are poorly understood and defy explanation by classical physics.

    The ALS is a synchrotron light source that can produce a wide spectrum of light, from infrared and ultraviolet light to X-rays. Synchrotrons accelerate electrons to nearly the speed of light, then direct them into curving paths that cause the electrons to give off some energy in the form of photons—fundamental particles of light. The electron storage ring at ALS is approximately 200 meters in circumference.

    ALS-U would utilize and preserve the existing ALS building, an iconic domed structure designed in the 1930s by Arthur Brown Jr., the architect who also designed Coit Tower, a San Francisco landmark.

    The upgrade would incorporate most of the 40 beamlines and supporting equipment that now allow simultaneous experiments across a wide range of scientific disciplines. Also, three new beamlines are planned that will be optimized for the new capabilities of ALS-U.

    A panoramic view of the interior of the Advanced Light Source. (Credit: Roy Kaltschmidt/Berkeley Lab)

    About 200 scientific and engineering staff work at the ALS, which draws thousands of scientist “users” per year from around the world. In fiscal year 2015, the ALS hosted more than 2,500 of these visiting scientists from 43 U.S. states and Washington, D.C., and 33 other nations. In collaboration with ALS staff experts, these scientists produce more than 900 peer-reviewed articles per year featuring work performed at the ALS.

    “For over 20 years the ALS has grown in its number of users and the breadth of publications,” Falcone said. “This upgrade will ensure that in the next 20 years we will continue on that growth path, serving even more scientists and doing more science at emerging frontiers.”

    The ALS dome was originally built in the 1940s to house an early particle accelerator known as the 184-inch cyclotron, a brainchild of Berkeley Lab founder Ernest O. Lawrence. Construction to convert the facility into the ALS began in 1988 and was completed in 1993. The ALS has undergone several improvements since startup—the latest was a four-year brightness improvement project, completed in 2013 and which recently received the Energy Secretary’s Achievement Award, that as much as tripled the brightness of X-ray light at some of its beamlines.

    ALS-U represents the largest new project at the lab since the ALS was completed, and takes advantage of a more than half-billion-dollar investment in the existing ALS, said Robin. ALS-U could conceivably be up and running within a decade, he added. The next stage of DOE project review and approval, known as CD-1, would confirm site selection for the proposed transformational soft-X-ray synchrotron project.

    The Advanced Light Source is a DOE Office of Science User Facility.

    For more information about the ALS-U project, visit: http://als.lbl.gov/als-u/overview.

    See the full article here .

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  • richardmitnick 2:33 pm on September 26, 2016 Permalink | Reply
    Tags: , , , , , , , uperconducting part of the European XFEL accelerator ready, X-ray Technology   

    From European XFEL: “Superconducting part of the European XFEL accelerator ready” 

    XFEL bloc

    European XFEL

    26 September 2016
    No writer credit found

    Ninety-six modules fully installed in 1.7-km long tunnel section.

    An important milestone in the construction of the X-ray laser European XFEL has been reached: The 1.7-km long superconducting accelerator is installed in the tunnel. The linear accelerator will accelerate bunches of free electrons flying at near-light speed to the extremely high energy of 17.5 gigaelectronvolts. The bunches are accelerated in devices called resonators, which are cooled to a temperature of -271°C. In the next part of the facility, the electron bunches are used to generate the flashes of X-ray light that will allow scientists new insights into the nanocosmos. The European XFEL accelerator will be put into operation step by step in the next weeks. It will be the largest and most powerful linear accelerator of its type in the world. On 6 October, the German Minister for Education and Research, Prof. Johanna Wanka, and the Polish Vice Minister of Science and Education Dr Piotr Dardziński, will officially initiate the commissioning of the X-ray laser, including the accelerator. User operation at the European XFEL is anticipated to begin in mid-2017.

    Responsible for the construction of the accelerator was an international consortium of 17 research institutes under the leadership of Deutsches Elektronen-Synchrotron (DESY), which is also the largest shareholder of the European XFEL.


    The central section consists of 96 accelerator modules, each 12 metres long, which contain almost 800 resonators made from ultrapure niobium surrounded by liquid helium. The electrons are accelerated inside of these resonators. The modules, which were industrially produced in cooperation with several partners, are on average about 16% more powerful than specified, so the original goal of 100 modules in the accelerator could be reduced to 96.

    Using a small box as a clean area, technicians make connections between two accelerator modules in the European XFEL tunnel in April.
    Heiner Müller-Elsner / European XFEL

    “I congratulate the accelerator team for this milestone and thank all partners for their perseverance and their tireless efforts”, said the Chairman of the DESY Board of Directors Helmut Dosch. “The individual teams involved meshed like the gears of a clock to build the world’s most powerful and modern linear accelerator. That all was delivered within a tight budget deserves the utmost respect.”

    “We are excited that the installation of the accelerator modules has been successfully completed”, said European XFEL Managing Director and Chairman of the Management Board Massimo Altarelli. “This is an important step on the way to user operation next year. On this path there were numerous challenges that, in the past months and years, we faced together successfully. I thank DESY and our European partners for their enormous effort, and we look together with excitement towards the next weeks and months, when the accelerator goes into operation.”

    The European XFEL accelerator tunnel. European XFEL

    The French project partner CEA in Saclay assembled the modules. Colleagues from the Polish partner institute IFJ-PAN in Kraków performed comprehensive tests of each individual module at DESY before it was installed in the 2-km long accelerator tunnel. Magnets for focusing and steering the electron beam inside the modules came from the Spanish research centre CIEMAT in Madrid. The niobium resonators were manufactured by companies in Germany and Italy, supervised by research centres DESY and INFN in Rome. Russian project partners such as the Efremov Institute in St. Petersburg and the Budker Institute in Novosibirsk delivered the different parts for vacuum components for the accelerator, within which the electron beam will be directed and focused in the non-superconducting portions of the facility at room temperature. Many other components were manufactured by DESY and their partners, including diagnostics and electron beam stabilization mechanisms, among others.

    In October, the accelerator is expected to move towards operation in several steps. As soon as the system for access control is installed, the interior of the modules can be slowly cooled to the operating temperature of two degrees above absolute zero—colder than outer space. Then DESY scientists can send the first electrons through the accelerator. At first, the electrons will be stopped in an “electron dump” at the end of the accelerator, until all of the beam properties are optimized. Then the electron beam will be sent further towards the X-ray light-generating magnetic structures called undulators. Here, the alternating poles of the undulator’s magnets will force the electron bunches to move in a tight, zigzagging “slalom” course for a 210-m stretch. In a self-amplifying intensification process, extremely short and bright X-ray flashes with laser-like properties will be generated. Reaching the conditions needed for this process is a massive technical challenge. Among other things, the electron bunches from the accelerator must meet precisely defined specifications. But the participating scientists have reason for optimism. All foundational principles and techniques have been proven at the free-electron laser FLASH at DESY, the prototype for the European XFEL. At European XFEL itself, the commissioning of the 30-m long injector has been complete since July. The injector generates the electron bunches for the main accelerator and accelerates them in an initial section to near-light speed.

    The beginning of user operation, the final step in the transition from the construction phase to the operation phase, is foreseen for summer 2017.

    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 8:06 am on September 18, 2016 Permalink | Reply
    Tags: , , , X-ray Technology   

    From Science Alert: “Here’s how physicists accelerate particles to 99.99% the speed of light” 


    Science Alert


    Business Insider

    15 SEP 2016

    NSLS II. Brookhaven National Laboratory

    By now, you might be familiar with the concept of particle accelerators through the work of the Large Hadron Collider (LHC), the monstrous accelerator that enabled scientists to detect the Higgs boson.

    CERN/LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    But the LHC is not alone – the world is equipped with more than 30,000 particle accelerators that are used for a seemingly endless variety of tasks.

    Some of these machines, like the LHC, accelerate particles to nearly the speed of light to smash them together and probe the fundamental building blocks of our universe. Others are used to seal milk cartons and bags of potato chips.

    Brookhaven National Laboratory in New York is home to one of the world’s most advanced particle accelerators: the National Synchrotron Light Source II (NSLS II).

    The NSLS II will allow researchers to do a wide range of science varying from developing better drug treatments, to building more advanced computer chips, to analysing everything from the molecules in your body to the soil you walk on.

    When scientists accelerate particles to these crazy speeds in the NSLS II, they force them to release energy which they can manipulate to do a mind-boggling array of different experiments.

    As electrons moving at nearly the speed of light go around turns, they lose energy in the form of radiation, such as X-rays. The X-rays produced at the NSLS II are extremely bright – a billion times brighter than the X-ray machine at your dentist’s office.

    When scientists focus this extremely bright light onto a very small spot, it allows them to probe matter at an atomic scale. It’s kind of like a microscope on steroids.

    Here’s how the NSLS II pushes particles to 99.99 percent the speed of light – all in the name of science.

    First, the electron gun generates electron beams and feeds them into the linear accelerator, or linac.

    In the linac, electromagnets and microwave radio-frequency fields are used to accelerate the electrons, which must travel in a vacuum to ensure they don’t bump into other particles and slow down.

    Next, the electrons enter a booster ring, where magnets and radio-frequency fields accelerate them to approximately 99.9 percent percent the speed of light.

    Then they are injected into a circular ring called a storage ring.

    Ali Sundermier

    In the storage ring, the electrons are steered by an assortment of magnets.

    The blue magnets bend the motion of the electrons, the yellow magnets focus and defocus the path of the electrons, and the red and orange magnets take outlying electrons and bring them into a closer path.

    The smaller magnets are corrector magnets, which keep the beam in line.

    Ali Sundermier

    This is an insertion device in the storage ring. Insertion devices are magnetic structures that wiggle the electron beam as it passes through the device. This produces an extremely bright and focused beam.

    Ali Sundermier

    As the electrons go around turns in the storage ring, they decelerate slightly, losing energy.

    The lost energy can be converted into different forms of electromagnetic radiation, such as X-rays, that are directed down beamlines running in straight lines tangential to the storage ring.

    At the end of the beamline, the X-rays crash into samples of whatever material is the subject of the experiment.

    Ali Sundermier

    This is an X-ray spectroscopy beamline, where scientists analyse the chemical composition of materials by exciting the electrons in an atom.

    Ali Sundermier

    The circumference of the NSLS-II is so big, nearly half a mile, that many people working there travel around on tricycles.

    The NSLS II is still in the early stages of its development, having just taken over for its successor (the NSLS), in 2014. When it’s complete, it will be able to accommodate about 70 different beamlines.

    Ali Sundermier

    This article was originally published by Business Insider.

    See the full article here .

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  • richardmitnick 11:15 am on September 9, 2016 Permalink | Reply
    Tags: , , Snapshots of molecules, X-ray Technology   

    From ANL: “Seeing energized light-active molecules proves quick work for Argonne scientists” 

    ANL Lab

    News from Argonne National Laboratory

    September 8, 2016
    Jared Sagoff

    For people who enjoy amusement parks, one of the most thrilling sensations comes at the top of a roller coaster, in the split second between the end of the climb and the rush of the descent. Trying to take a picture at exactly the moment that the roller coaster reaches its zenith can be difficult because the drop happens so suddenly.

    For chemists trying to take pictures of energized molecules, the dilemma is precisely the same, if not trickier. When certain molecules are excited – like a roller coaster poised at the very top of its run – they often stay in their new state for only an instant before “falling” into a lower energy state.

    To understand how molecules undergo light-driven chemical transformations, scientists need to be able to follow the atoms and electrons within the energized molecule as it rides on the energy “roller coaster.”

    In a recent study, a team of researchers at the U.S. Department of Energy’s (DOE’s) Argonne National Laboratory, Northwestern University, the University of Washington and the Technical University of Denmark used the ultrafast high-intensity pulsed X-rays produced by the Linac Coherent Light Source (LCLS), a DOE Office of Science User Facility at SLAC National Accelerator Laboratory, to take molecular snapshots of these molecules.


    By using the LCLS, the researchers were able to capture atomic and electronic arrangements within the molecule that had lifetimes as short as 50 femtoseconds – which is about the amount of time it takes light to travel the width of a human hair.

    “We can see changes in these energized molecules which happen incredibly quickly,” said Lin Chen, an Argonne senior chemist and professor of chemistry at Northwestern University who led the research.

    Chen and her team looked the structure of a metalloporphyrin, a molecule similar to important building blocks for natural and artificial photosynthesis. Metalloporphyrins are of interest to scientists who seek to convert solar energy into fuel by splitting water to generate hydrogen or converting carbon dioxide into sugars or other types of fuels.

    Specifically, the research team examined how the metalloporphyrin changes after it is excited with a laser. They discovered an extremely short-lived “transient state” that lasted only a few hundred femtoseconds before the molecule relaxed into a lower energy state.

    “Although we had previously captured the molecular structure of a longer-lived state, the structure of this transient state eluded our detection because its lifetime was too short,” Chen said.

    When the laser pulse hits the molecule, an electron from the outer ring moves into the nickel metal center. This creates a charge imbalance, which in turn creates an instability within the whole molecule. In short order, another electron from the nickel migrates back to the outer ring, and the excited electron falls back into the lower open orbital to take its place.

    “This first state appears and disappears so quickly, but it’s imperative for the development of things like solar fuels,” Chen said. “Ideally, we want to find ways to make this state last longer to enable the subsequent chemical processes that may lead to catalysis, but just being able to see that it is there in the first place is important.”

    The challenge, Chen said, is to prolong the lifetime of the excited state through the design of the metalloporphyrin molecule. “From this study, we gained knowledge of which molecular structural element, such as bond length and planarity of the ring, can influence the excited state property,” Chen said. “With these results we might be able to design a system to allow us to harvest much of the energy in the excited state.”

    A paper based on the research, “Ultrafast excited state relaxation of a metalloporphyrin revealed by femtosecond X-ray absorption spectroscopy,” was published in the June 10 online edition of the Journal of the American Chemical Society.

    The research was funded by the DOE’s Office of Science and by the National Institute of Health.

    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 4:35 pm on August 31, 2016 Permalink | Reply
    Tags: , , X-ray Technology   

    From LBNL: “Researchers Peel Back Another Layer of Chemistry with ‘Tender’ X-rays” 

    Berkeley Logo

    Berkeley Lab

    August 31, 2016
    Glenn Roberts Jr.

    Berkeley Lab’s Ethan Crumlin, working with other researchers, found a new way to study chemical processes at work in batteries and in other chemical reactions using a specialized X-ray toolkit developed at the lab’s Advanced Light Source, an X-ray source. The technique was pioneered at the ALS’s Beam Line 9.3.1. (Credit: Marilyn Chung/Berkeley Lab)

    Scientists can now directly probe a previously hard-to-see layer of chemistry thanks to a unique X-ray toolkit developed at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab). The X-ray tools and techniques could be extended, researchers say, to provide new insight about battery performance and corrosion, a wide range of chemical reactions, and even biological and environmental processes that rely on similar chemistry.

    In a first-of-its-kind experiment at Berkeley Lab’s Advanced Light Source [ALS], an X-ray source known as a synchrotron, researchers demonstrated this new, direct way to study the inner workings of an activity center in chemistry known as an “electrochemical double layer” that forms where liquids meets solids—where battery fluid (the electrolyte) meets an electrode, for example (batteries have two electrodes: an anode and a cathode).

    LBL Advanced Light Source

    A key breakthrough enabling the latest experiment was in tailoring “tender” X-rays—which have an energy range tuned in a middle ground between the typical high-energy (or “hard”) and low-energy (or “soft”) X-rays used in research—to focus on chemistry within the double layer of a sample electrochemical system. The related study was published Aug. 31 in Nature Communications.

    Drilling down on the double layer

    In a battery, this electrochemical double layer describes the layer of charged atoms or molecules in the battery’s fluid that are drawn in and cling to the surface of the electrode because of their opposite electrical charge—an essential step in battery operation—and a second and closely related zone of chemical activity that is affected by the chemistry at the electrode’s surface. The complex molecular-scale dance of charge flow and transfer within a battery’s double layer is central to its function.

    This stylized representation shows an electrochemical double layer, the heart of solid/liquid chemical interactions such as those occurring around a battery’s electrode. An experiment at Berkeley Lab used X-rays to study the properties of the double layer that formed as positively or negatively charged particles (ions, shown as plus and minus symbols) were drawn to a gold electrode (left). The experiment featured neutrally charged pyrazine molecules (dark blue) suspended in a water-based electrolyte, composed of potassium hydroxide. Researchers precisely measured changes in the charge properties of molecules caused by changes to the electric charge applied to the electrode and to the ion concentration of the electrolyte in the double-layer region. (Credit: Zosia Rostomian/Berkeley Lab)

    The latest work shows changes in the electric “potential” in this double layer. This potential is a location-based measure of the effect of an electric field on an object—an increased potential would be found in an electric charge moving toward a lightbulb, and flows to a lower potential after powering on the lightbulb.

    “To be able to directly probe any attribute of the double layer is a significant advancement,” said Ethan Crumlin, a research scientist at Berkeley Lab’s ALS who led the experiment. “Essentially, we now have a direct map, showing how potential within the double layer changes based on adjustments to the electrode charge and electrolyte concentration. Independent of a model, we can directly see this—it’s literally a picture of the system at that time.”

    He added, “This will help us with guidance of theoretical models as well as materials design and development of improved electrochemical, environmental, biological, and chemical systems.”

    New technique confronts decades-old problem

    Zahid Hussain, division deputy for scientific support at the ALS, who participated in the experiment, added, “The problem of understanding solid/liquid interfaces has been known for 50-plus years—everybody has been using simulations and modeling to try to conceive of what’s at work.” The latest work has narrowed the list of candidate models that explain what’s at work in the double layer.

    Hussain more than a decade ago had helped to pioneer X-ray tools and techniques at the ALS, which dozens of other research sites have since adopted, that allow researchers to study another important class of chemical reactions: those that occur between solids and gases.

    There was a clear need to create new study tools for solid/liquid reactions, too, he said. “Solid/liquid interfaces are key for all kinds of research, from batteries to fuel cells to artificial photosynthesis,” the latter which seeks to synthesize plants’ conversion of sunlight into energy.

    Hubert Gasteiger, a chemistry professor at the Technical University of Munich and the university’s chair of technical electrochemistry who is familiar with the latest experiment, said, “This work is already quite applicable to real problems,” as it provides new insight about the potential distribution within the double layer.

    “No one has been able to look into this roughly 10-nanometer-thin region of the electrochemical double layer in this way before,” he said. “This is one of the first papers where you have a probe of the potential distribution here. Using this tool to validate double-layer models I think would give us insight into many electrochemical systems that are of industrial relevance.”

    Probing active chemistry in changing conditions

    In the experiment, researchers from Berkeley Lab and Shanghai studied the active chemistry of a gold electrode and a water-containing electrolyte that also contained a neutrally charged molecule called pyrazine. They used a technique called ambient pressure X-ray photoelectron spectroscopy (APXPS) to measure the potential distribution for water and pyrazine molecules across the solid/liquid interface in response to changes in the electrode potential and the electrolyte concentration.

    A view inside the experimental chamber used in a chemistry experiment at Berkeley Lab’s Advanced Light Source. Researchers used ‘tender’ X-rays to explore a nanometers-thick region known as the electrochemical double layer at ALS Beam Line 9.3.1. (Credit: Marilyn Chung)

    The experiment demonstrated a new, direct way to precisely measure a potential drop in the stored electrical energy within the double layer’s electrolyte solution. These measurements also allowed researchers to determine associated charge properties across the interface (known as the “potential of zero charge” or “pzc”).

    Upgrade, new beamline will enhance studies

    Importantly, the technique is well-suited to active chemistry, and there are plans to add new capabilities to make this technique more robust for studying finer details during the course of chemical reactions, and to bring in other complementary X-ray study techniques to add new details, Hussain said.

    An upgrade to the X-ray beamline where the experiment was conducted is now in progress and is expected to conclude early next year. Also, a brand new beamline that will marry this and several other X-ray capabilities for energy-related research, dubbed AMBER (Advanced Materials Beamline for Energy Research) is under construction at the ALS and is scheduled to begin operating in 2018.

    “What’s absolutely key to these new experiments is that they will be carried out in actual, operating conditions—in a working electrochemical cell,” Hussain said. “Ultimately, we will be able to understand how a material behaves down to the level of electrons and atoms, and also to understand charge-transfer and corrosion,” a key problem in battery longevity.

    Researchers from the Joint Center for Artificial Photosynthesis, the Joint Center for Energy Storage Research, the Gwangju Institute of Science and Technology in the Republic of Korea, the Shanghai Institute of Microsystem and Information Technology in China, and the School of Physical Science and Technology in China participated in this research. The work was supported by the U.S. Department of Energy Office Science, the National Natural Science Foundation of China, and the Chinese Academy of Sciences-Shanghai Science Research Center.

    The Advanced Light Source is a DOE Office of Science User Facility.

    See the full article here .

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  • richardmitnick 7:39 pm on August 29, 2016 Permalink | Reply
    Tags: , , X-ray Technology   

    From SLAC: “Poof! The Weird Case of the X-ray that Came Out Blank” 

    SLAC Lab

    August 29, 2016

    A ‘Nonlinear’ Effect that Seemingly Turns Materials Transparent is Seen for the First Time in X-rays at SLAC’s LCLS

    An illustration shows what happens in a typical experiment with SLAC’s LCLS X-ray laser, top, versus what happened in this study with an especially intense X-ray pulse. Normally the X-ray pulses — which are shown coming in from the right — scatter off electrons in a sample and produce a pattern in a detector. But when researchers cranked up the intensity of the X-ray pulses, the pulses seemed to go straight through the sample, as if it were not there, and the pattern in the detector vanished. Two recent papers describe and explain this surprising result, which is due to a ‘nonlinear’ effect where particles of X-ray light team up to cause unexpected things to happen. (SLAC National Accelerator Laboratory)

    Imagine getting a medical X-ray that comes out blank – as if your bones had vanished. That’s what happened when scientists cranked up the intensity of the world’s first X-ray laser, at the Department of Energy’s SLAC National Accelerator Laboratory, to get a better look at a sample they were studying: The X-rays seemed to go right through it as if it were not there.

    This result was so weird that the leader of the experiment, SLAC Professor Joachim Stöhr, devoted the next three years to developing a theory that explains why it happened. Now his team has published a paper in Physical Review Letters describing the 2012 experiment for the first time.

    What they saw was a so-called nonlinear effect where more than one photon, or particle of X-ray light, enters a sample at the same time, and they team up to cause unexpected things to happen.

    “In this case, the X-rays wiggled electrons in the sample and made them emit a new beam of X-rays that was identical to the one that went in,” said Stöhr, who is an investigator with the Stanford Institute for Materials and Energy Sciences at SLAC. “It continued along the same path and hit a detector. So from the outside, it looked like a single beam went straight through and the sample was completely transparent.”

    This effect, called “stimulated scattering,” had never been seen in X-rays before. In fact, it took an extremely intense beam from SLAC’s Linac Coherent Light Source (LCLS), which is a billion times brighter than any X-ray source before it, to make this happen.


    A Milestone in Understanding How Light Interacts with Matter

    The observation is a milestone in the quest to understand how light interacts with matter, Stöhr said.

    “What will we do with it? I think we’re just starting to learn. This is a new phenomenon and I don’t want to speculate,” he said. “But it opens the door to controlling the electrons that are closest to the core of atoms ­– boosting them into higher orbitals, and driving them back down in a very controlled manner, and doing this over and over again.”

    Nonlinear optical effects are nothing new. They were discovered in the1960s with the invention of the laser – the first source of light so bright that it could send more than one photon into a sample at a time, triggering responses that seemed all out of proportion to the amount of light energy going in. Scientists use these effects to shift laser light to much higher energies and focus optical microscopes on much smaller objects than anyone had thought possible.

    The 2009 opening of LCLS as a DOE Office of Science User Facility introduced another fundamentally new tool, the X-ray free-electron laser, and scientists have spent a lot of time since then figuring out exactly what it can do. For instance, a SLAC-led team recently published [Nature Physics] the first report of nonlinear effects produced by its brilliant pulses.

    “The X-ray laser is really a quantum leap, the equivalent of going from a light bulb to an optical laser,” Stöhr said. “So it’s not just that you have more X-rays. The interaction of the X-rays with the sample is very different, and there are effects you could never see at other types of X-ray light sources.”

    “The X-ray laser is really a quantum leap, the equivalent of going from a light bulb to an optical laser,” Stöhr said. “So it’s not just that you have more X-rays. The interaction of the X-rays with the sample is very different, and there are effects you could never see at other types of X-ray light sources.”

    A Most Puzzling Result

    Stöhr stumbled on this latest discovery by accident. Then director of LCLS, he was working with Andreas Scherz, a SLAC staff scientist, who is now with the soon-to-open European XFEL in Hamburg, Germany, and Stanford graduate student Benny Wu to look at the fine structure of a common magnetic material used in data storage.

    To enhance the contrast of their image, they tuned the LCLS beam to a wavelength that would resonate with cobalt atoms in the sample and amplify the signal in their detector. The initial results looked great. So they turned up the intensity of the laser beam in the hope of making the images even sharper.

    That’s when the speckled pattern they’d been seeing in their detector went blank, as if the sample had disappeared.

    “We thought maybe we had missed the sample, so we checked the alignment and tried again,” Stöhr said. “But it kept happening. We knew this was strange – that there was something here that needed to be understood.”

    Stöhr is an experimentalist, not a theorist, but he was determined to find answers. He and Scherz dove deeply into the scientific literature. Meanwhile Wu finished his PhD thesis, which described the experiment and its unexpected result, and went on to a job in industry. But the team held off on publishing their experimental results in a scientific journal until they could explain what happened.

    Stöhr and Scherz published their explanation last fall in Physical Review Letters.

    “We are developing a whole new field of nonlinear X-ray science, and our study is just one building block in this field,” Stöhr said. “We are basically opening Pandora’s box, learning about all the different nonlinear effects, and eventually some of those will turn out to be more important than others.”

    The study included other collaborators from SLAC and Stanford, and was funded by the DOE Office of Science.

    See the full article here .

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  • richardmitnick 10:18 am on August 18, 2016 Permalink | Reply
    Tags: , New X-Ray Matter Interaction Observed at Ultra-High Intensity, , X-ray Technology   

    From SLAC via DOE: “New X-Ray Matter Interaction Observed at Ultra-High Intensity” 

    SLAC Lab


    Basic Energy Sciences

    Previously unobserved scattering shows unexpected sensitivity to bound electrons, providing new insights into x-ray interactions with matter and opening the door to new probes of matter.

    David A. Reis
    Stanford PULSE Institute

    Artistic rendering of an intense x-ray beam interacting with metallic beryllium. In the central part of the image, two photons (white lines) interact simultaneously with a single electron of one of the beryllium atoms (sphere), emitting the electron (red streak) and a single higher energy photon (wavy blue line), while leaving the atom in an excited state (purple-blue color). Researchers found that the spectrum of the emitted high-energy photon disagreed with theoretical predictions. Image courtesy of Joel Brehm.

    The Science

    For the first time, researchers explored an extremely rare, but fundamental, process, in which two packets of light called photons scatter simultaneously from a single electron—in this case, from individual atoms in a beryllium metal target. Using the extremely high intensity x-ray laser at the Linac Coherent Light Source, they found that the details of this process deviated dramatically from expectations based on the usual assumption that the electrons behaved as quasi-free in the x-ray interaction.


    The researchers explain this anomaly in terms of a new x-ray matter interaction that they predict to have unprecedented specificity for light elements, like beryllium.

    The Impact

    In addition to providing new fundamental insights about x-ray interactions, this discovery has broad implications for understanding and controlling the fastest processes in chemical reactivity and energy conversion. The work may lead to powerful new probe techniques at x-ray free electron laser facilities to provide fundamental understanding of ultrafast chemical processes.


    The basis for atomic‐scale structure determination involves the scattering of single x‐ray photons, one at a time, from the electrons that make up all materials. Spatial resolution is achieved through a combination of the short wavelength of x-rays and the concentration of the electron density around the individual atoms. For x-ray interactions, these atomic electrons generally behave almost as if they were free. In special cases involving heavy atoms, researchers can achieve simultaneously a level of chemical specificity and spatial resolution, but this is not the case for the lighter atoms that are ubiquitous in most biological and energy-relevant materials. Thus, new methods to achieve chemical specificity for light atoms in structure determination would be revolutionary. In the current work, the researchers used the unprecedented x-ray intensity produced by the Linac Coherent Light Source x-ray laser to observe the concerted nonlinear Compton scattering of two identical hard x-ray photons from the light element beryllium to produce a single higher-energy photon. Not only did the researchers make the first observation of this fundamental process, they also observed an anomalously large shift toward longer wavelengths for the scattered photon. The large wavelength shift is indicative of an interaction that shows properties of scattering from bound (non-free) electrons, which implies that this process could be used as a chemically specific probe. Furthermore, because the nonlinear interaction requires the x-rays to coincide at precisely the same location in time and space, the mechanism is also applicable to studying the fastest processes involving electron motion in chemical reactivity and energy conversion.


    This work was supported primarily by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences (BES) and the Volkswagen Foundation. Portions of this research were carried out at the Linac Coherent Light Source (LCLS) at the SLAC National Accelerator Laboratory. Preparatory measurements were carried out at the Stanford Synchrotron Radiation Light Source (SSRL). Both LCLS and SSRL are Office of Science user facilities operated for the U.S. Department of Energy’s Office of Science by Stanford University.

    M. Fuchs, et al., Anomalous nonlinear x-ray Compton scattering. Nature Physics 11, 964 (2015). [DOI: 10.1038/nphys3452]

    See the full article here .

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  • richardmitnick 12:00 pm on August 13, 2016 Permalink | Reply
    Tags: , , , Light sources, , , X-ray Technology   

    From CERN Courier: “MAX IV paves the way for ultimate X-ray microscope” 

    CERN Courier

    Sweden’s MAX IV facility is the first storage ring to employ a multi-bend achromat. Mikael Eriksson and Dieter Einfeld describe how this will produce smaller and more stable X-ray beams, taking synchrotron science closer to the X-ray diffraction limit.

    Aug 12, 2016

    Mikael Eriksson, Maxlab, Lund, Sweden,
    Dieter Einfeld, ESRF, Grenoble, France.


    Since the discovery of X-rays by Wilhelm Röntgen more than a century ago, researchers have striven to produce smaller and more intense X-ray beams. With a wavelength similar to interatomic spacings, X-rays have proved to be an invaluable tool for probing the microstructure of materials. But a higher spectral power density (or brilliance) enables a deeper study of the structural, physical and chemical properties of materials, in addition to studies of their dynamics and atomic composition.

    For the first few decades following Röntgen’s discovery, the brilliance of X-rays remained fairly constant due to technical limitations of X-ray tubes. Significant improvements came with rotating-anode sources, in which the heat generated by electrons striking an anode could be distributed over a larger area. But it was the advent of particle accelerators in the mid-1900s that gave birth to modern X-ray science. A relativistic electron beam traversing a circular storage ring emits X-rays in a tangential direction. First observed in 1947 by researchers at General Electric in the US, such synchrotron radiation has taken X-ray science into new territory by providing smaller and more intense beams.

    Generation game

    First-generation synchrotron X-ray sources were accelerators built for high-energy physics experiments, which were used “parasitically” by the nascent synchrotron X-ray community. As this community started to grow, stimulated by the increased flux and brilliance at storage rings, the need for dedicated X-ray sources with different electron-beam characteristics resulted in several second-generation X-ray sources. As with previous machines, however, the source of the X-rays was the bending magnets of the storage ring.

    The advent of special “insertion devices” led to present-day third-generation storage rings – the first being the European Synchrotron Radiation Facility (ESRF) in Grenoble, France, and the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory in Berkeley, California, which began operation in the early 1990s.

    ESRF. Grenoble, France
    ESRF. Grenoble, France


    Instead of using only the bending magnets as X-ray emitters, third-generation storage rings have straight sections that allow periodic magnet structures called undulators and wigglers to be introduced. These devices consist of rows of short magnets with alternating field directions so that the net beam deflection cancels out. Undulators can house 100 or so permanent short magnets, each emitting X-rays in the same direction, which boosts the intensity of the emitted X-rays by two orders of magnitude. Furthermore, interference effects between the emitting magnets can concentrate X-rays of a given energy by another two orders of magnitude.

    Third-generation light sources have been a major success story, thanks in part to the development of excellent modelling tools that allow accelerator physicists to produce precise lattice designs. Today, there are around 50 third-generation light sources worldwide, with a total number of users in the region of 50,000. Each offers a number of X-ray beamlines (up to 40 at the largest facilities) that fan out from the storage ring: X-rays pass through a series of focusing and other elements before being focused on a sample positioned at the end station, with the longest beamlines (measuring 150 m or more) at the largest light sources able to generate X-ray spot sizes a few tens of nanometres in diameter. Facilities typically operate around the clock, during which teams of users spend anywhere between a few hours to a few days undertaking experimental shifts, before returning to their home institutes with the data.

    Although the corresponding storage-ring technology for third-generation light sources has been regarded as mature, a revolutionary new lattice design has led to another step up in brightness. The MAX IV facility at Maxlab in Lund, Sweden, which was inaugurated in June, is the first such facility to demonstrate the new lattice. Six years in construction, the facility has demanded numerous cutting-edge technologies – including vacuum systems developed in conjunction with CERN – to become the most brilliant source of X-rays in the world.

    Iron-block magnets

    Initial ideas for the MAX IV project started at the end of the 20th century. Although the flagship of the Maxlab laboratory, the low-budget MAX II storage ring, was one of the first third-generation synchrotron radiation sources, it was soon outcompeted by several larger and more powerful sources entering operation. Something had to be done to maintain Maxlab’s accelerator programme.

    The dominant magnetic lattice at third-generation light sources consists of double-bend achromats (DBAs), which have been around since the 1970s.

    MAX IV undulator

    A typical storage ring contains 10–30 achromats, each consisting of two dipole magnets and a number of magnet lenses: quadrupoles for focusing and sextupoles for chromaticity correction (at MAX IV we also added octupoles to compensate for amplitude-dependent tune shifts). The achromats are flanked by straight sections housing the insertion devices, and the dimensions of the electron beam in these sections is minimised by adjusting the dispersion of the beam (which describes the dependence of an electron’s transverse position on its energy) to zero. Other storage-ring improvements, for example faster correction of the beam orbit, have also helped to boost the brightness of modern synchrotrons. The key quantity underpinning these advances is the electron-beam emittance, which is defined as the product of the electron-beam size and its divergence.

    Despite such improvements, however, today’s third-generation storage rings have a typical electron-beam emittance of between 2–5 nm rad, which is several hundred times larger than the diffraction limit of the X-ray beam itself. This is the point at which the size and spread of the electron beam approaches the diffraction properties of X-rays, similar to the Abbe diffraction limit for visible light. Models of machine lattices with even smaller electron-beam emittances predict instabilities and/or short beam lifetimes that make the goal of reaching the diffraction limit at hard X-ray energies very distant.

    Although it had been known for a long time that a larger number of bends decreases the emittance (and therefore increases the brilliance) of storage rings, in the early 1990s, one of the present authors (DE) and others recognised that this could be achieved by incorporating a higher number of bends into the achromats. Such a multi-bend achromat (MBA) guides electrons around corners more smoothly, therefore decreasing the degradation in horizontal emittance. A few synchrotrons already employ triple-bend achromats, and the design has also been used in several particle-physics machines, including PETRA at DESY, PEP at SLAC and LEP at CERN, proving that a storage ring with an energy of a few GeV produces a very low emittance.

    DESY Petra III interior
    DESY Petra III

    PEP II at SLAC. http://www.sciencephoto.com/media/613/view


    To avoid prohibitively large machines, however, the MBA demands much smaller magnets than are currently employed at third-generation synchrotrons.

    In 1995, our calculations showed that a seven-bend achromat could yield an emittance of 0.4 nm rad for a 400 m-circumference machine – 10 times lower than the ESRF’s value at the time. The accelerator community also considered a six-bend achromat for the Swiss Light Source and a five-bend achromat for a Canadian light source, but the small number of achromats in these lattices meant that it was difficult to make significant progress towards a diffraction-limited source. One of us (ME) took the seven-bend achromat idea and turned it into a real engineering proposal for the design of MAX IV. But the design then went through a number of evolutions. In 2002, the first layout of a potential new source was presented: a 277 m-circumference, seven-bend lattice that would reach an emittance of 1 nm rad for a 3 GeV electron beam. By 2008, we had settled on an improved design: a 520 m-circumference, seven-bend lattice with an emittance of 0.31 nm rad, which will be reduced by a factor of two once the storage ring is fully equipped with undulators. This is more or less the design of the final MAX IV storage ring.

    In total, the team at Maxlab spent almost a decade finding ways to keep the lattice circumference at a value that was financially realistic, and even constructed a 36 m-circumference storage ring called MAX III to develop the necessary compact magnet technology. There were tens of problems that we had to overcome. Also, because the electron density was so high, we had to elongate the electron bunches by a factor of four by using a second radio-frequency (RF) cavity system.

    Block concept

    MAX IV stands out in that it contains two storage rings operated at an energy of 1.5 and 3 GeV. Due to the different energies of each, and because the rings share an injector and other infrastructure, high-quality undulator radiation can be produced over a wide spectral range with a marginal additional cost. The storage rings are fed electrons by a 3 GeV S-band linac made up of 18 accelerator units, each comprising one SLAC Energy Doubler RF station. To optimise the economy over a potential three-decade-long operation lifetime, and also to favour redundancy, a low accelerating gradient is used.

    The 1.5 GeV ring at MAX IV consists of 12 DBAs, each comprising one solid-steel block that houses all the DBA magnets (bends and lenses). The idea of the magnet-block concept, which is also used in the 3 GeV ring, has several advantages. First, it enables the magnets to be machined with high precision and be aligned with a tolerance of less than 10 μm without having to invest in aligning laboratories. Second, blocks with a handful of individual magnets come wired and plumbed direct from the delivering company, and no special girders are needed because the magnet blocks are rigidly self-supporting. Last, the magnet-block concept is a low-cost solution.

    We also needed to build a different vacuum system, because the small vacuum tube dimensions (2 cm in diameter) yield a very poor vacuum conductance. Rather than try to implement closely spaced pumps in such a compact geometry, our solution was to build 100% NEG-coated vacuum systems in the achromats. NEG (non-evaporable getter) technology, which was pioneered at CERN and other laboratories, uses metallic surface sorption to achieve extreme vacuum conditions. The construction of the MAX IV vacuum system raised some interesting challenges, but fortunately CERN had already developed the NEG coating technology to perfection. We therefore entered a collaboration that saw CERN coat the most intricate parts of the system, and licences were granted to companies who manufactured the bulk of the vacuum system. Later, vacuum specialists from the Budker Institute in Novosibirsk, Russia, mounted the linac and 3 GeV-ring vacuum systems.

    Due to the small beam size and high beam current, intra beam scattering and “Touschek” lifetime effects must also be addressed. Both are due to a high electron density at small-emittance/high-current rings in which electrons are brought into collisions with themselves. Large energy changes among the electrons bring some of them outside of the energy acceptance of the ring, while smaller energy deviations cause the beam size to increase too much. For these reasons, a low-frequency (100 MHz) RF system with bunch-elongating harmonic cavities was introduced to decrease the electron density and stabilise the beam. This RF system also allows powerful commercial solid-state FM-transmitters to be used as RF sources.

    When we first presented the plans for the radical MAX IV storage ring in around 2005, people working at other light sources thought we were crazy. The new lattice promised a factor of 10–100 increase in brightness over existing facilities at the time, offering users unprecedented spatial resolutions and taking storage rings within reach of the diffraction limit. Construction of MAX IV began in 2010 and commissioning began in August 2014, with regular user operation scheduled for early 2017.

    On 25 August 2015, an amazed accelerator staff sat looking at the beam-position monitor read-outs at MAX IV’s 3 GeV ring. With just the calculated magnetic settings plugged in, and the precisely CNC-machined magnet blocks, each containing a handful of integrated magnets, the beam went around turn after turn with proper behaviour. For the 3 GeV ring, a number of problems remained to be solved. These included dynamic issues – such as betatron tunes, dispersion, chromaticity and emittance – in addition to more trivial technical problems such as sparking RF cavities and faulty power supplies.

    As of MAX IV’s inauguration on 21 June, the injector linac and the 3 GeV ring are operational, with the linac also delivering X-rays to the Short Pulse Facility. A circulating current of 180 mA can be stored in the 3 GeV ring with a lifetime of around 10 h, and we have verified the design emittance with a value in the region of 300 pm rad. Beamline commissioning is also well under way, with some 14 beamlines under construction and a goal to increase that number to more than 20.

    Sweden has a well-established synchrotron-radiation user community, although around half of MAX IV users will come from other countries. A variety of disciplines and techniques are represented nationally, which must be mirrored by MAX IV’s beamline portfolio. Detailed discussions between universities, industry and the MAX IV laboratory therefore take place prior to any major beamline decisions. The high brilliance of the MAX IV 3 GeV ring and the temporal characteristics of the Short Pulse Facility are a prerequisite for the most advanced beamlines, with imaging being one promising application.

    Towards the diffraction limit

    MAX IV could not have reached its goals without a dedicated staff and help from other institutes. As CERN has helped us with the intricate NEG-coated vacuum system, and the Budker Institute with the installation of the linac and ring vacuum systems, the brand new Solaris light source in Krakow, Poland (which is an exact copy of the MAX IV 1.5 GeV ring) has helped with operations, and many other labs have offered advice. The MAX IV facility has also been marked out for its environmental credentials: its energy consumption is reduced by the use of high-efficiency RF amplifiers and small magnets that have a low power consumption. Even the water-cooling system of MAX IV transfers heat energy to the nearby city of Lund to warm houses.

    The MAX IV ring is the first of the MBA kind, but several MBA rings are now in construction at other facilities, including the ESRF, Sirius in Brazil and the Advanced Photon Source (APS) at Argonne National Laboratory [ANL] in the US.


    The ESRF is developing a hybrid MBA lattice that would enter operation in 2019 and achieve a horizontal emittance of 0.15 nm rad. The APS has decided to pursue a similar design that could enter operation by the end of the decade and, being larger than the ESRF, the APS can strive for an even lower emittance of around 0.07 nm rad. Meanwhile, the ALS in California is moving towards a conceptual design report, and Spring-8 in Japan is pursuing a hybrid MBA that will enter operation on a similar timescale.

    Indeed, a total of some 10 rings are currently in construction or planned. We can therefore look forward to a new generation of synchrotron storage rings with very high transverse-coherent X-rays. We will then have witnessed an increase of 13–14 orders of magnitude in the brightness of synchrotron X-ray sources in a period of seven decades, and put the diffraction limit at high X-ray energies firmly within reach.

    One proposal would see such a diffraction-limited X-ray source installed in the 6.3 km-circumference tunnel that once housed the Tevatron collider at Fermilab, Chicago. Perhaps a more plausible scenario is PETRA IV at DESY in Hamburg, Germany. Currently the PETRA III ring is one of the brightest in the world, but this upgrade (if it is funded) could result in a 0.007 nm rad (7 pm rad) emittance or even lower. Storage rings will then have reached the diffraction limit at an X-ray wavelength of 1 Å. This is the Holy Grail of X-ray science, providing the highest resolution and signal-to-noise ratio possible, in addition to the lowest-radiation damage and the fastest data collection. Such an X-ray microscope will allow the study of ultrafast chemical reactions and other processes, taking us to the next chapter in synchrotron X-ray science.

    Further reading

    E Al-Dmour et al. 2014 J. Synchrotron Rad. 21 878.
    D Einfeld et al. 1995 Proceedings: PAC p177.
    M Eriksson et al. 2008 NIM-A 587 221.
    M Eriksson et al. 2016 IPAC 2016, MOYAA01, Busan, Korea.
    MAX IV Detailed Design Report http://www.maxlab.lu.se/maxlab/max4/index.html.

    See the full article here .

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  • richardmitnick 2:40 pm on August 12, 2016 Permalink | Reply
    Tags: , , X-ray Technology   

    From BNL: “Slicing Through Materials with a New X-ray Imaging Technique” 

    Brookhaven Lab

    August 12, 2016
    Chelsea Whyte,
    (631) 344-8671

    Peter Genzer,
    (631) 344-3174

    Images reveal battery materials’ chemical reactions in five dimensions – 3D space plus time and energy

    The chemical phase within the battery evolves as the charging time increases. The cut-away views reveal a change from anisotropic to isotropic phase boundary motion. No image credit

    Researchers at the U.S. Department of Energy’s Brookhaven National Laboratory have created a new imaging technique that allows scientists to probe the internal makeup of a battery during charging and discharging using different x-ray energies while rotating the battery cell. The technique produces a three-dimensional chemical map and lets the scientists track chemical reactions in the battery over time in working conditions. Their work is published in the August 12 issue of Nature Communications.

    Getting an accurate image of the activity inside a battery as it charges and discharges is a difficult task. Often even x-ray images don’t provide researchers with enough information about the internal chemical changes in a battery material because two-dimensional images can’t separate out one layer from the next. Imagine taking an x-ray image of a multi-story office building from above. You’d see desks and chairs on top of one another, several floors of office spaces blending into one picture. But it would be difficult to know the exact layout of any one floor, let alone to track where one person moved throughout the day.

    Getting an accurate image of the activity inside a battery as it charges and discharges is a difficult task. Often even x-ray images don’t provide researchers with enough information about the internal chemical changes in a battery material because two-dimensional images can’t separate out one layer from the next. Imagine taking an x-ray image of a multi-story office building from above. You’d see desks and chairs on top of one another, several floors of office spaces blending into one picture. But it would be difficult to know the exact layout of any one floor, let alone to track where one person moved throughout the day.

    “It’s very challenging to carry out in-depth study of in situ energy materials, which requires accurately tracking chemical phase evolution in 3D and correlating it to electrochemical performance,” said Jun Wang, a physicist at the National Synchrotron Light Source II, who led the research.

    Using a working lithium-ion battery, Wang and her team tracked the phase evolution of the lithium iron phosphate within the electrode as the battery charged. They combined tomography (a kind of x-ray imaging technique that displays the 3D structure of an object) with X-ray Absorption Near Edge Structure (XANES) spectroscopy (which is sensitive to chemical and local electronic changes). The result was a “five dimensional” image of the battery operating: a full three-dimensional image over time and at different x-ray energies.

    To make this chemical map in 3D, they scanned the battery cell at a range of energies that included the “x-ray absorption edge” of the element of interest inside the electrode, rotating the sample a full 180 degrees at each x-ray energy, and repeating this procedure at different stages as the battery was charging. With this method, each three-dimensional pixel—called a voxel—produces a spectrum that is like a chemical-specific “fingerprint” that identifies the chemical and its oxidation state in the position represented by that voxel. Fitting together the fingerprints for all voxels generates a chemical map in 3D.

    The scientists found that, during charging, the lithium iron phosphate transforms into iron phosphate, but not at the same rate throughout the battery. When the battery is in the early stage of charging, this chemical evolution occurs in only certain directions. But as the battery becomes more highly charged, the evolution proceeds in all directions over the entire material.

    “Were these images to have been taken with a standard two-dimensional method, we wouldn’t have been able to see these changes,” Wang said.

    “Our unprecedented ability to directly observe how the phase transformation happens in 3D reveals accurately if there is a new or intermediate phase during the phase transformation process. This method gives us precise insight into what is happening inside the battery electrode and clarifies previous ambiguities about the mechanism of phase transformation,” Wang said.

    Wang said modeling will help the team explore the way the spread of the phase change occurs and how the strain on the materials affects this process.

    This work was completed at the now-closed National Synchrotron Light Source (NSLS), which housed a transmission x-ray microscope (TXM) developed by Wang using DOE funds made available through American Recovery and Reinvestment Act of 2009. This TXM instrument will be relocated to Brookhaven’s new light source, NSLS-II, which produces x-rays 10,000 times brighter than its predecessor. Both NSLS and NSLS-II are DOE Office of Science User Facilities.

    “At NSLS-II, this work can be done incredibly efficiently,” she said. “The stability of the beam lends itself to good tomography, and the flux is so high that we can take images more quickly and catch even faster reactions.”

    This work was supported by the DOE Office of Science.

    See the full article here .

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

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