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  • richardmitnick 12:44 pm on August 5, 2013 Permalink | Reply
    Tags: , , , , , , Stanford Synchrotron Radiation Lightsource (SSRL)   

    From Stanford: “Disorder can improve the performance of plastic solar cells, Stanford scientists say” 

    Stanford University Name
    Stanford University

    Instead of mimicking rigid solar cells made of silicon crystals, scientists should embrace the inherently disordered nature of plastic polymers, a Stanford study has found

    August 4, 2013
    Mark Shwartz

    “Scientists have spent decades trying to build flexible plastic solar cells efficient enough to compete with conventional cells made of silicon. To boost performance, research groups have tried creating new plastic materials that enhance the flow of electricity through the solar cell. Several groups expected to achieve good results by redesigning pliant polymers of plastic into orderly, silicon-like crystals, but the flow of electricity did not improve.

    Recently, scientists discovered that disorder at the molecular level actually improves the polymers’ performance. Now Stanford University researchers have an explanation for this surprising result. Their findings, published in the Aug. 4 online edition of the journal Nature Materials, could speed up the development of low-cost, commercially available plastic solar cells.

    cell
    These X-ray images reveal the microscopic structure of two semiconducting plastic polymers. The bottom image, with several big crystals stacked in a row, is from a highly ordered polymer sample. The top image shows a disordered polymer with numerous tiny crystals that are barely discernible.

    ‘People used to think that if you made the polymers more like silicon they would perform better,’ said study co-author Alberto Salleo, an associate professor of materials science and engineering at Stanford. ‘But we found that polymers don’t naturally form nice, well-ordered crystals. They form small, disordered ones, and that’s perfectly fine.’

    Instead of trying to mimic the rigid structure of silicon, Salleo and his colleagues recommend that scientists learn to cope with the inherently disordered nature of plastics.”

    X-ray analysis

    To observe the disordered materials at the microscopic level, the Stanford team took samples to the SLAC National Accelerator Laboratory for X-ray analysis. The X-rays revealed a molecular structure resembling a fingerprint gone awry. Some polymers looked like amorphous strands of spaghetti, while others formed tiny crystals just a few molecules long.

    ‘The crystals were so small and disordered you could barely infer their presence from X-rays,’ Salleo said. ‘In fact, scientists had assumed they weren’t there.’

    By analyzing light emissions from electricity flowing through the samples, the Stanford team determined that numerous small crystals were scattered throughout the material and connected by long polymer chains, like beads in a necklace. The small size of the crystals was a crucial factor in improving overall performance, Salleo said.

    Other authors of the study are postdoctoral scholar Koen Vandewal of Stanford; Felix Koch and Paul Smith of ETH Zurich; Natalie Stingelin of Imperial College London; and Michael Toney of the SLAC Stanford Synchrotron Radiation Lightsource.”

    See the full article here.

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

    Stanford University Seal


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  • richardmitnick 1:29 pm on July 8, 2013 Permalink | Reply
    Tags: , , , SLAC SPEAR, , Stanford Synchrotron Radiation Lightsource (SSRL)   

    From SLAC: “SPEAR-heading X-ray Science for 40 Years” 

    July 8, 2013
    Manuel Gnida

    “Last Saturday marked the 40th anniversary of an historic event: In 1973, a team of research pioneers extracted hard X-rays for the first time from SLAC’s SPEAR accelerator. Like X-rays from an X-ray tube, the radiation generated by SPEAR can deeply penetrate a large variety of materials and probe their inner structures. However, SPEAR’s X-rays are significantly more intense and unlock the possibility for brand new science.

    spear

    Forty years later, SPEAR has matured into SPEAR3 and is running stronger than ever, providing X-rays to SLAC’s Stanford Synchrotron Radiation Lightsource (SSRL). And accelerator-based X-ray research at more than 60 facilities around the world has led to numerous breakthroughs in the materials, life, environmental and other sciences.

    SPEAR was originally built for electron-positron collisions, from which particle physicists gained insights into nature’s fundamental particles and forces. However, it was quickly realized that particle racetracks like SPEAR also produce a byproduct called synchrotron radiation – an intense light with a large spectral range that includes X-rays. Consequently, in 1968, SLAC’s Burton Richter and Wolfgang “Pief” Panofsky granted Stanford University researcher William Spicer’s request to consider the possibility of using SPEAR’s X-rays for experiments, and added a tangential spout to the accelerator’s design as an outlet for this synchrotron radiation.

    ssrl
    Stanford Synchrotron Radiation Project pilot project beamline inside SPEAR, 07/06/1973. (SLAC Archives)

    See the full article here.

    SLAC Campus
    SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.
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  • richardmitnick 9:10 am on November 28, 2012 Permalink | Reply
    Tags: , , , , , , Stanford Synchrotron Radiation Lightsource (SSRL)   

    From Brookhaven Lab: “X-rays Illuminate Nitrogen’s Role in Single-layer Graphene” 


    Brookhaven Lab

    Laura Mgrdichian

    “Researchers using x-rays to study a single-atom-thick layer of carbon, called graphene, have learned new information about its atomic bonding and electronic properties when the material is “doped” with nitrogen atoms. They show that synchrotron x-ray techniques can be excellent tools to study and better understand the behavior of doped graphene, which is being eyed for use as a promising contact material in electronic devices due to its many desirable traits, including a high conductivity and, most notably, tunable electronic properties.

    gr
    Graphene is an atomic-scale honeycomb lattice made of carbon atoms. (Wikipedia)

    In this work, the researchers discovered that several bond types may be present between carbon and nitrogen atoms, even within the same graphene sheet. This results in profoundly different effects on the charge carrier concentration across the sheet, which is not ideal.

    The paper’s co-authors include colleagues at Columbia University as well as the Stanford Synchrotron Radiation Lightsource (SSRL), CNR-Nanoscience Institute (Italy), Sejong University (Korea), the National Institute of Standards and Technology, Stockholm University (Sweden), and Brookhaven National Laboratory [Brookhaven NSLS is referenced.].

    See the full article here.

    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. 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 11:22 am on November 20, 2012 Permalink | Reply
    Tags: , , , Stanford Synchrotron Radiation Lightsource (SSRL),   

    From SLAC Lab: “SSRL Users Have It Made in the Shade” 

    November 20, 2012
    Lori Ann White

    “Two major multi-year projects reached successful conclusions during the annual shutdown of the Stanford Synchrotron Radiation Lightsource. The projects, a wrapping of insulation over the SPEAR3 tunnel and the installation of new hardware and software at several beamlines, promise to provide many users with steadier X-ray beams that are easier to control.

    image
    The new detector installed at Beam Line 11-2 is constructed from a single piece of germanium. (Photo by Matt Beardsley)

    ‘SSRL has once more completed a busy shutdown with a range of important projects, focusing on improvements and new capabilities, making us ready to provide our user community enhanced capabilities for their research,’ said interim SSRL director Piero Pianetta.

    The insulation around the SPEAR3 storage ring, where circling electrons generate the X-rays that power scientific discoveries at SSRL’s many beamlines, is a cost-effective solution to an issue that has dogged the ring for several years. ‘It prevents temperature differences across the concrete blocks that make up the ring,’ said John Schmerge, head of the SPEAR3 accelerator division. In previous years such temperature differences would cause the floor of the ring to rise tens of microns, lifting the electron beam and ultimately throwing the X-rays off their targets in the experimental hutches.

    Had one part of the structure moved with respect to another, the differences could have given Schmerge’s team clues as to the source of the shift. But when the floor moved, the entire accelerator moved with it in concert. ‘The electron sensors said the beam wasn’t moving,’ even though the X-ray detectors along the experimental floor disagreed, Schmerge said. Although feedback mechanisms helped them correct the beam’s wanderings, they wanted to address the motion itself.”

    There is more too this story, read the whole article here.

    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 5:39 pm on October 23, 2012 Permalink | Reply
    Tags: , , , , , , Stanford Synchrotron Radiation Lightsource (SSRL)   

    From SLAC Today: “SSRL Yields Clues to Function of Vital Protein Family” 

    October 23, 2012
    Lori Ann White

    “A team of Stanford University researchers used the Stanford Synchrotron Radiation Lightsource. to gain a deeper understanding of a vital family of signaling proteins responsible for regulating an organism’s development and growth, as well as tissue regeneration and wound healing. The protein family, known by the collective name ‘Wnt,’ can cause havoc when their signals go astray; mistakes in Wnt signaling are associated with the development of many types of cancer, including colon cancer, breast cancer and melanoma, and degenerative diseases like multiple sclerosis, Alzheimer’s and type 2 diabetes.

    graph
    Overview of signal transduction pathways. On the upper right hand side of the cell, a Wnt signaling protein is shown to bind to a frizzled receptor. Wikipedia

    protein
    XWnt8, a member of the family of signaling proteins called “Wnt” proteins, has an unusual structure resembling a fist with an outstretched thumb and index finger. No image credit.

    See the full article here.

    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 11:24 am on March 5, 2012 Permalink | Reply
    Tags: , , , , , Stanford Synchrotron Radiation Lightsource (SSRL)   

    From SLAC Today: “X-rays Reveal How Soil Bacteria Carry Out Surprising Chemistry” 

    Discovery paves the way for new synthesis of antibiotics

    March 5, 2012
    Lori Ann White

    “Researchers working at SLAC have used powerful X-rays to help decipher how certain natural antibiotics defy a longstanding set of chemical rules – a mechanism that has baffled organic chemists for decades.

    Their result, reported today in Nature, details how five carbon atoms and one oxygen atom in the structure of lasalocid, a natural antibiotic produced by bacteria in soil, can link into a six-membered ring through an energetically unfavorable chemical reaction. Unlocking this chemical pathway could enable scientists to synthesize many important chemicals currently found only in nature.

    ‘Our study has a broad implication because the six-membered ring is a common structural feature found in hundreds of drug molecules produced by nature,’ said the study’s principal investigator, Chu-Young Kim of the National University of Singapore. ‘We have actually analyzed the genes of six other organisms that produce similar drugs and we are now confident that the chemical mechanism we have uncovered applies to these other organisms as well.’

    mo
    A ribbon diagram of the protein Lsd19, which catalyzes the formation of six-membered rings in lasalocid. Image by Kinya Hotta

    To determine the protein’s atomic structure, the researchers hit frozen crystals of Lsd19 with X-rays from SLAC’s Stanford Synchrotron Radiation Lightsource and observed how the crystals diffracted the X-rays passing through. ‘You need atomic-level detail of the crystal’s structure to understand what’s really happening,” said co-author Irimpan Mathews, a staff scientist at SLAC.”

    See the full article here.

    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. i1

     
  • richardmitnick 10:43 am on September 27, 2011 Permalink | Reply
    Tags: , , , Stanford Synchrotron Radiation Lightsource (SSRL)   

    From SLAC Today: “From Parchment to People: SLAC Invention Measures Stroke Damage in the Brain” 

    September 27, 2011
    by Glennda Chui

    “A technique SLAC scientists invented for scanning ancient manuscripts is now being used to probe the human brain, in research that could lead to new medical imaging methods and better treatments for stroke and other brain conditions.

    The studies, taking place at SLAC’s Stanford Synchrotron Radiation Lightsource, are led by cell biologist Helen Nichol, of the University of Saskatchewan, with $2.5 million in funding from the Canadian government and the Heart and Stroke Foundation of Canada.

    Her team, which includes a Stanford neurosurgeon and stem cell expert, other medical doctors and experts in stroke research and medical imaging, reflects the broad ambitions of this research: to give doctors a better understanding of what they’re seeing in MRI scans of stroke patients; to improve diagnosis and guide treatments; and maybe even to develop new ways to peer inside the living brain. What all these goals have in common is that they depend on the ability to track movements and deposits of tiny traces of metal in human tissue. That’s a job the SSRL technique, known as rapid-scanning XRF, is exquisitely suited to do.”

    i1
    Damage from a stroke is visible about midway down this slice of human brain, on the far right. A technique invented at SLAC allows researchers to rapidly scan brain tissue and identify areas where bleeding has occurred. Photo courtesy Helen Nichol

    i2
    From left: Team leader Helen Nichol of the University of Saskatchewan with postdoctoral researchers Angela Auriat of Stanford School of Medicine, Weili Zheng of Wayne State University and Zhouping Wei of the University of Saskatchewan, during an experimental run at SLAC’s Stanford Synchrotron Radiation Lightsource.

    See the full article here.

    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. i1

     
  • richardmitnick 8:54 am on August 31, 2011 Permalink | Reply
    Tags: , , , , , Stanford Synchrotron Radiation Lightsource (SSRL)   

    From Brookhaven Lab: “A Material’s Magnetic Surprise Could Mean New Technologies” 

    By Laura Mgrdichian
    August 28, 2011

    “Scientists working at the National Synchrotron Light Source have discovered an unusually fragile, unstable magnetic state in a member of a class of materials known for its robust magnetic behaviors. Their discovery could lead to applications in the emerging field of spintronics – electronics based not on electric charge but on electron spin, a property that is very closely linked to magnetism.

    The research was published on July 15, 2011, in the online edition of Physical Review Letters. It was performed by researchers from NSLS, the Stanford Synchrotron Radiation Lightsource at SLAC National Accelerator Laboratory, Pohang University of Science and Technology (Korea), Rutgers University, and the University of Illinois.

    i1
    The layered structure of the bilayer manganite.

    The material under study is a compound of the elements manganese (Mn), lanthanum (La), and strontium (Sr), and belongs to a family of materials called bilayer manganites.

    ‘We clearly demonstrate that the interplay among charge, orbitals, spin, and lattice degrees of freedom leads to exotic phenomena in these materials, said SLAC researcher Jun-Sik Lee, who led the study. ‘Moreover, this finding demonstrates the rich variety of spin couplings in these materials, which may be useful in engineering spintronic devices for our future.’”

    See the full article here.

    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. 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 3:53 pm on June 7, 2011 Permalink | Reply
    Tags: , , Stanford Synchrotron Radiation Lightsource (SSRL)   

    At SLAC Today: “Hydrogen Storage Goes Nano” 

    “A team of Stanford and SLAC researchers recently investigated the interaction of hydrogen with such single-walled carbon nanotubes coated with platinum nanoparticles. Experiments at Beamline 13-2 of the Stanford Synchrotron Radiation Lightsource [SSRL] revealed that the addition of platinum as a catalyst made it possible for hydrogen to bond with the carbon nanotubes at realistic conditions (<10 atmospheric pressure at room temperature). This research shows that carbon nanotubes doped with a suitable metal catalyst, such as platinum, represent viable materials for hydrogen storage. However, much work remains before these nanotubes can achieve the Department of Energy goal of 6 percent weight efficiency.

    To expand the use of hydrogen in mobile applications-such as hydrogen-powered buses and cars-researchers will need to design lightweight, compact means of storing it. One possible method is to store hydrogen inside carbon nanotubes. Theoretical predictions suggest that, through a mechanism that forms stable carbon-hydrogen bonds, it would be possible to store one hydrogen atom for every carbon atom inside single-walled carbon nanotubes."

    i1
    Schematic of the “spillover” mechanism by which platinum nanoparticles (tan) helps make it possible to store hydrogen (purple) in single-walled carbon nanotubes (gray).

    Visit SLAC Today for the news from this D.O.E. lab

     
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