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Storage Ring (storage + ring)
Selected AbstractsSynchrotron-Based Micro-CT and Refraction-Enhanced Micro-CT for Non-Destructive Materials Characterisation,ADVANCED ENGINEERING MATERIALS, Issue 6 2009Bernd R. Müller Abstract X-ray computed tomography is an important tool for non-destructively evaluating the 3-D microstructure of modern materials. To resolve material structures in the micrometer range and below, high brilliance synchrotron radiation has to be used. The Federal Institute for Materials Research and Testing (BAM) has built up an imaging setup for micro-tomography and -radiography (BAMline) at the Berliner storage ring for synchrotron radiation (BESSY). In computed tomography, the contrast at interfaces within heterogeneous materials can be strongly amplified by effects related to X-ray refraction. Such effects are especially useful for materials of low absorption or mixed phases showing similar X-ray absorption properties that produce low contrast. The technique is based on ultra-small-angle scattering by microstructural elements causing phase-related effects, such as refraction and total reflection. The extraordinary contrast of inner surfaces is far beyond absorption effects. Crack orientation and fibre/matrix debonding in plastics, polymers, ceramics and metal-matrix-composites after cyclic loading and hydro-thermal aging can be visualized. In most cases, the investigated inner surface and interface structures correlate to mechanical properties. The technique is an alternative to other attempts on raising the spatial resolution of CT machines. [source] A dedicated small-angle X-ray scattering beamline with a superconducting wiggler source at the NSRRCJOURNAL OF SYNCHROTRON RADIATION, Issue 1 2009Din-Goa Liu At the National Synchrotron Radiation Research Center (NSRRC), which operates a 1.5,GeV storage ring, a dedicated small-angle X-ray scattering (SAXS) beamline has been installed with an in-achromat superconducting wiggler insertion device of peak magnetic field 3.1,T. The vertical beam divergence from the X-ray source is reduced significantly by a collimating mirror. Subsequently the beam is selectively monochromated by a double Si(111) crystal monochromator with high energy resolution (,E/E, 2 × 10,4) in the energy range 5,23,keV, or by a double Mo/B4C multilayer monochromator for 10,30 times higher flux (,1011,photons,s,1) in the 6,15,keV range. These two monochromators are incorporated into one rotating cradle for fast exchange. The monochromated beam is focused by a toroidal mirror with 1:1 focusing for a small beam divergence and a beam size of ,0.9,mm × 0.3 mm (horizontal × vertical) at the focus point located 26.5,m from the radiation source. A plane mirror installed after the toroidal mirror is selectively used to deflect the beam downwards for grazing-incidence SAXS (GISAXS) from liquid surfaces. Two online beam-position monitors separated by 8,m provide an efficient feedback control for an overall beam-position stability in the 10,µm range. The beam features measured, including the flux density, energy resolution, size and divergence, are consistent with those calculated using the ray-tracing program SHADOW. With the deflectable beam of relatively high energy resolution and high flux, the new beamline meets the requirements for a wide range of SAXS applications, including anomalous SAXS for multiphase nanoparticles (e.g. semiconductor core-shell quantum dots) and GISAXS from liquid surfaces. [source] IKNO, a user facility for coherent terahertz and UV synchrotron radiationJOURNAL OF SYNCHROTRON RADIATION, Issue 6 2008Fernando Sannibale IKNO (Innovation and KNOwledge) is a proposal for a multi-user facility based on an electron storage ring optimized for the generation of coherent synchrotron radiation (CSR) in the terahertz frequency range, and of broadband incoherent synchrotron radiation ranging from the IR to the VUV. IKNO can be operated in an ultra-stable CSR mode with photon flux in the terahertz frequency region up to nine orders of magnitude higher than in existing third-generation light sources. Simultaneously to the CSR operation, broadband incoherent synchrotron radiation up to VUV frequencies is available at the beamline ports. The main characteristics of the IKNO storage and its performance in terms of CSR and incoherent synchrotron radiation are described in this paper. The proposed location for the infrastructure facility is Sardinia, Italy. [source] Comparison of calculated brightness and flux of radiation from a long-period wiggler and a short-period undulatorJOURNAL OF SYNCHROTRON RADIATION, Issue 4 2008T. Shaftan In this article the calculation of brightness and flux for two insertion devices of the 2.8,GeV X-ray storage ring at the NSLS is discussed. The radiation properties from the X25 linearly polarized wiggler and the new X25 short-period undulator are compared at a fixed photon energy (11.3,keV) corresponding to emission from the fifth harmonic of the short-period undulator. For this computation, three commonly available synchrotron radiation programs are used. The capabilities of each of these codes are briefly discussed, and their range of applicability are commented on. It is concluded that special care is needed when modeling the radiation of the classes of insertion devices considered here. [source] X-ray beam-position monitoring in the sub-micrometre and sub-second regimeJOURNAL OF SYNCHROTRON RADIATION, Issue 6 2005Oliver Bunk It is demonstrated that X-ray beam positions can be extracted from two-dimensional profiles with sub-pixel resolution. Beam-position measurements utilizing a self-designed low-cost two-dimensional detector have been performed at two synchrotron radiation beamlines of the Swiss Light Source. The effective detector pixel size was 4.8,µm and the resolution achieved for the beam position was about 5,nm. At a data rate of 25 frames per second, periodic variations of the beam position could be detected with a frequency resolution below 0.1,Hz. This allowed, for example, the influence of a turbo-pump in the X-ray optics hutch on the beam position to be quantified, and even minute variations related to the electron beam in the storage ring could be detected. [source] Small-gap insertion-device development at the National Synchrotron Light Source , performance of the new X13 mini-gap undulatorJOURNAL OF SYNCHROTRON RADIATION, Issue 2 2004J. M. Ablett The National Synchrotron Light Source (NSLS) 2.8,GeV electron storage ring continues to set high standards in insertion-device research and development. The Chasman,Green NSLS lattice design provides for dispersion-free long straight sections in addition to a very small vertical , function. As the electron beam size is proportional to the square root of this function, a program to exploit this feature was undertaken more than a decade ago by implementing short-period small-gap insertion devices in the NSLS storage ring. The possibility of utilizing existing moderate-energy synchrotron radiation electron storage rings to produce high-brightness photon beams into the harder X-ray region have been realised using in-vacuum undulators. In this article the operation of a 1.25,cm-period mini-gap undulator, operating down to a gap of 3.3,mm within the NSLS X13 straight section, is reported. It is the brightest source of hard X-rays in the energy range ,3.7,16,keV at the NSLS, and replaces an in-vacuum undulator which had a more limited tunability. [source] Two-dimensional visible synchrotron light interferometry for transverse beam-profile measurement at the SPring-8 storage ringJOURNAL OF SYNCHROTRON RADIATION, Issue 4 2003Mitsuhiro Masaki A two-dimensional visible synchrotron light interferometer has been developed to measure the transverse profile of an electron beam at the SPring-8 storage ring. The new interferometer enables the simultaneous measurement of beam sizes along the major and minor axes and the beam-tilt angle of an assumed elliptical Gaussian distribution. The principle of the interferometer is explained through basic formulae. To calibrate the point-spread function of the interferometer, a simple error model was assumed for disturbances in the amplitude and phase of the light; these disturbances were presumably caused by optical elements, such as mirrors and lenses. The experimental method to determine the parameters in the error model is shown. To verify the two-dimensional profiling capabilities of the interferometer, an electron beam stored in the SPring-8 storage ring operated at various working points was observed. A beam broadening from 20 to 120,µm in the vertical direction and changes in the beam-tilt angle were clearly observed at working points close to the differential resonance. However, the vertical spatial resolution is limited by the available vertical separation of the apertures of the diffracting mask because of the narrow aperture of the upstream vacuum duct. [source] Synchrotron X-ray topography of electronic materialsJOURNAL OF SYNCHROTRON RADIATION, Issue 3 2002T. Tuomi Large-area transmission, transmission section, large-area back-reflection, back-reflection section and grazing-incidence topography are the geometries used when recording high-resolution X-ray diffraction images with synchrotron radiation from a bending magnet, a wiggler or an undulator of an electron or a positron storage ring. Defect contrast can be kinematical, dynamical or orientational even in the topographs recorded on the same film at the same time. In this review article limited to static topography experiments, examples of defect studies on electronic materials cover the range from voids and precipitates in almost perfect float-zone and Czochralski silicon, dislocations in gallium arsenide grown by the liquid-encapsulated Czochralski technique, the vapour-pressure controlled Czochralski technique and the vertical-gradient freeze technique, stacking faults and micropipes in silicon carbide to misfit dislocations in epitaxic heterostructures. It is shown how synchrotron X-ray topographs of epitaxic laterally overgrown gallium arsenide layer structures are successfully explained by orientational contrast. [source] A new high-speed beam chopper for time-resolved X-ray studiesJOURNAL OF SYNCHROTRON RADIATION, Issue 1 2000Armon McPherson A new high-speed X-ray beam chopper, which can be phase locked to the temporal structure of the Advanced Photon Source (APS) storage ring, has been developed and tested. The open window time of the chopper is 2450,ns, which corresponds to ,67% of the revolution time of the APS storage ring. By phase locking the rotation of the beam chopper to the storage-ring orbital frequency, any portion of the storage-ring fill pattern can be positioned within the beam-chopper transmission-time window. [source] SB7: the new bending-magnet double-headed dragon beamline at SuperACOJOURNAL OF SYNCHROTRON RADIATION, Issue 1 2000Fausto Sirotti A new beamline is now operational at LURE on bending-magnet 7 of the SuperACO storage ring in Orsay. The monochromator is of the `dragon' type, designed to work in the energy range 150,1500,eV, and is equipped with a double vertical focusing mirror in order to allow for fast switching of light polarization. In this paper the results of photoion-yield experiments performed on N2, Ar and Ne gases are presented. The observed resonance structures enable us to determine the available energy resolution: a resolving power higher than 8500 is obtained at the Ar,2p, N,1s and Ne,K -edges when using all the optical elements at full aperture. The total flux as a function of the measured photon energy resolution and the characterization of the double-head behaviour in delivering circularly polarized light are reported. [source] Cloning, purification, crystallization and preliminary X-ray analysis of the receiver domain of the histidine kinase CKI1 from Arabidopsis thalianaACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 5 2009Klumpler The receiver domain (RD) of a sensor histidine kinase (HK) catalyses the transphosphorylation reaction during the action of HKs in hormonal and abiotic signalling in plants. Crystals of the recombinant RD of the Arabidopsis thaliana HK CYTOKININ-INDEPENDENT1 (CKI1RD) have been obtained by the hanging-drop vapour-diffusion method using ammonium sulfate as a precipitant and glycerol as a cryoprotectant. The crystals diffracted to approximately 2.4,Å resolution on beamline BW7B of the DORIS-III storage ring. The diffraction improved significantly after the use of a non-aqueous cryoprotectant. Crystals soaked in Paratone-N diffracted to at least 2.0,Å resolution on beamline BW7B and their mosaicity decreased more than tenfold. The crystals belonged to space group C2221, with unit-cell parameters a = 54.46, b = 99.82, c = 79.94,Å. Assuming the presence of one molecule of the protein in the asymmetric unit gives a Matthews coefficient VM of 2.33,Å3,Da,1. A molecular-replacement solution has been obtained and structure refinement is in progress. [source] Small-gap insertion-device development at the National Synchrotron Light Source , performance of the new X13 mini-gap undulatorJOURNAL OF SYNCHROTRON RADIATION, Issue 2 2004J. M. Ablett The National Synchrotron Light Source (NSLS) 2.8,GeV electron storage ring continues to set high standards in insertion-device research and development. The Chasman,Green NSLS lattice design provides for dispersion-free long straight sections in addition to a very small vertical , function. As the electron beam size is proportional to the square root of this function, a program to exploit this feature was undertaken more than a decade ago by implementing short-period small-gap insertion devices in the NSLS storage ring. The possibility of utilizing existing moderate-energy synchrotron radiation electron storage rings to produce high-brightness photon beams into the harder X-ray region have been realised using in-vacuum undulators. In this article the operation of a 1.25,cm-period mini-gap undulator, operating down to a gap of 3.3,mm within the NSLS X13 straight section, is reported. It is the brightest source of hard X-rays in the energy range ,3.7,16,keV at the NSLS, and replaces an in-vacuum undulator which had a more limited tunability. [source] Variable-period undulators as synchrotron radiation sourcesJOURNAL OF SYNCHROTRON RADIATION, Issue 3 2003G. K. Shenoy A concept for variable-period undulators for the production of synchrotron radiation from both medium- and high-energy storage rings is described. This concept is based on a staggered array of permeable poles placed in a magnetic solenoid that produces a longitudinal field. The concept permits variations in the short magnetic period of the undulator of as much as 100%. The unique capabilities of such undulators will allow them to be tuned by the variation of the period length and of the solenoid field. The device can be operated at either constant flux or constant power, independent of X-ray energy. It is expected that the new concept will have a major impact on the production and applications of X-rays because of the inherent simplicity and flexibility of the design and the absence of radiation damage. Analyses of the magnetic and mechanical design concepts are presented. [source] The historical development of cryogenically cooled monochromators for third-generation synchrotron radiation sourcesJOURNAL OF SYNCHROTRON RADIATION, Issue 2 2000Donald H. Bilderback In the period of the late-1980s, before the construction of multi-GeV third-generation storage rings with their intense insertion-device sources, the perceived number one problem for X-ray instrumentation was proper cooling of the first optical element in the beamline. This article, first given as an acceptance speech for the Compton Award ceremony at the Advanced Photon Source, presents a somewhat historical and anecdotal overview of how cryogenically cooled monochromator optics have been developed to provide a monochromator cooling solution adequate for today's power levels. A series of workshops and international collaborations were the key components for the progress and final success of this development. [source] Mass and lifetime measurements of exotic nuclei in storage ringsMASS SPECTROMETRY REVIEWS, Issue 5 2008Bernhard Franzke Abstract Mass and lifetime measurements lead to the discovery and understanding of basic properties of matter. The isotopic nature of the chemical elements, nuclear binding, and the location and strength of nuclear shells are the most outstanding examples leading to the development of the first nuclear models. More recent are the discoveries of new structures of nuclides far from the valley of stability. A new generation of direct mass measurements which allows the exploration of extended areas of the nuclear mass surface with high accuracy has been opened up with the combination of the Experimental Storage Ring ESR and the FRragment Separator FRS at GSI Darmstadt. In-flight separated nuclei are stored in the ring. Their masses are directly determined from the revolution frequency. Dependent on the half-life two complementary methods are applied. Schottky Mass Spectrometry SMS relies on the measurement of the revolution frequency of electron cooled stored ions. The cooling time determines the lower half-life limit to the order of seconds. For Isochronous Mass Spectrometry IMS the ring is operated in an isochronous ion-optical mode. The revolution frequency of the individual ions coasting in the ring is measured using a time-of-flight method. Nuclides with lifetimes down to microseconds become accessible. With SMS masses of several hundreds nuclides have been measured simultaneously with an accuracy in the 2,×,10,7 -range. This high accuracy and the ability to study large areas of the mass surface are ideal tools to discover new nuclear structure properties and to guide improvements for theoretical mass models. In addition, nuclear half-lives of stored bare and highly charged ions have been measured. This new experimental development is a significant progress since nuclear decay characteristics are mostly known for neutral atoms. For bare and highly charged ions new nuclear decay modes become possible, such as bound-state beta decay. Dramatic changes in the nuclear lifetime have been observed in highly charged ions compared to neutral atoms due to blocking of nuclear decay channels caused by the modified atomic interaction. High ionization degrees prevail in hot stellar matter and thus these experiments have great relevance for the understanding of the synthesis of elements in the universe and astrophysical scenarios in general. © 2008 Wiley Periodicals, Inc., Mass Spec Rev 27: 428,469, 2008 [source] | ||||||||||