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X-ray scattering experiments at synchrotron sources are characterized by large and constantly increasing amounts of data. The great number of files generated during a synchrotron experiment is often a limiting factor in the analys...
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X-ray scattering experiments at synchrotron sources are characterized by large and constantly increasing amounts of data. The great number of files generated during a synchrotron experiment is often a limiting factor in the analysis of the data, since appropriate software is rarely available to perform fast and tailored data processing. Furthermore, it is often necessary to perform online data reduction and analysis during the experiment in order to interactively optimize experimental design. This article presents an open-source software package developed to process large amounts of data from synchrotron scattering experiments. These data reduction processes involve calibration and correction of raw data, one-or two-dimensional integration, as well as fitting and further analysis of the data, including the extraction of certain parameters. The software, DPDAK (directly programmable data analysis kit), is based on a plug-in structure and allows individual extension in accordance with the requirements of the user. The article demonstrates the use of DPDAK for on-and offline analysis of scanning small-angle X-ray scattering (SAXS) data on biological samples and microfluidic systems, as well as for a comprehensive analysis of grazing-incidence SAXS data. In addition to a comparison with existing software packages, the structure of DPDAK and the possibilities and limitations are discussed.
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A small-angle X-ray scattering beamline BioMUR has been constructed and is now in operation at the Kurchatov synchrotron radiation source (Moscow Russian Federation). Using X-ray optic elements and equipment of the former beamline...
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A small-angle X-ray scattering beamline BioMUR has been constructed and is now in operation at the Kurchatov synchrotron radiation source (Moscow Russian Federation). Using X-ray optic elements and equipment of the former beamlines DICSY (Kurchatov source) and X33 (EMBL c/o DESY) Hamburg, Germany, BioMUR has been commissioned to deliver an optimized configuration that provides a significant improvement in the quality of small-angle scattering patterns at the Kurchatov synchrotron radiation source. It allows one to study a wide spectrum of samples at different conditions using the automated control software.
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In this paper, we present the generalities of the Compton interaction process; we analyse the different paradigms of Inverse Compton Sources, implemented or in commissioning phase at various facilities, or proposed as future proje...
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In this paper, we present the generalities of the Compton interaction process; we analyse the different paradigms of Inverse Compton Sources, implemented or in commissioning phase at various facilities, or proposed as future projects. We present an overview of the state of the art, with a discussion of the most demanding challenges.
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The brilliance of undulator X-ray sources can be used to develop microfocusing optics for wide-angle (WAXS) and small-angle (SAXS) X-ray scattering. At the ESRF microfocus beamline, a beam size of 10 mu m is obtained by a pinhole ...
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The brilliance of undulator X-ray sources can be used to develop microfocusing optics for wide-angle (WAXS) and small-angle (SAXS) X-ray scattering. At the ESRF microfocus beamline, a beam size of 10 mu m is obtained by a pinhole collimating system coupled to a double focusing mirror. This allows resolving the first order of collagen (67 nm). Glass capillary optics provides a beam size close to one micron, however, with a more limited resolution. A high resolution CCD detector allows combined SAXS/WAXS experiments for one detector setting. [References: 19]
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We present a detailed synchrotron x-ray scattering study of the charge-density-wave (CDW) order in simple tetragonal HgBa_2CuO_(4+δ) (Hg1201). Resonant soft x-ray scattering measurements reveal that short-range order appears at a...
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We present a detailed synchrotron x-ray scattering study of the charge-density-wave (CDW) order in simple tetragonal HgBa_2CuO_(4+δ) (Hg1201). Resonant soft x-ray scattering measurements reveal that short-range order appears at a temperature that is distinctly lower than the pseudogap temperature and in excellent agreement with a prior transient reflectivity result. Despite considerable structural differences between Hg1201 and YBa_2Cu_3O_(6+δ) , the CDWcorrelations exhibit similar doping dependencies, and we demonstrate a universal relationship between the CDWwave vector and the size of the reconstructed Fermi pocket observed in quantum oscillation experiments. The CDWcorrelations in Hg1201 vanish already below optimal doping, once the correlation length is comparable to the CDWmodulation period, and they appear to be limited by the disorder potential from unit cells hosting two interstitial oxygen atoms. A complementary hard x-ray diffraction measurement, performed on an underdoped Hg1201 sample in magnetic fields along the crystallographic c axis of up to 16 T, provides information on the form factor of the CDW order. As expected from the single-CuO_2-layer structure of Hg1201, the CDW correlations vanish at half-integer values of L and appear to be peaked at integer L. We conclude that the atomic displacements associated with the short-range CDW order are mainly planar, within the CuO_2 layers.
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Narrow bandwidth, high energy photon sources can be generated by Thomson scattering of laser light from energetic electrons, and detailed control of the interaction is needed to produce high quality sources. We present analytic ca...
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Narrow bandwidth, high energy photon sources can be generated by Thomson scattering of laser light from energetic electrons, and detailed control of the interaction is needed to produce high quality sources. We present analytic calculations of the energy-angular spectra and photon yield that parametrize the influences of the electron and laser beam parameters to allow source design. These calculations, combined with numerical simulations, are applied to evaluate sources using conventional scattering in vacuum and methods for improving the source via laser waveguides or plasma channels. We show that the photon flux can be greatly increased by using a plasma channel to guide the laser during the interaction. Conversely, we show that to produce a given number of photons, the required laser energy can be reduced by an order of magnitude through the use of a plasma channel. In addition, we show that a plasma can be used as a compact beam dump, in which the electron beam is decelerated in a short distance, thereby greatly reducing radiation shielding. Realistic experimental errors such as transverse jitter are quantitatively shown to be tolerable. Examples of designs relevant to nuclear resonance fluorescence and photofission are provided.
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This paper compares very different physical principles of X-ray production to spur ideation. Since more than 120 years, bremsstrahlung from X-ray tubes has been the workhorse of medical diagnostics. Generated by X-ray segments com...
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This paper compares very different physical principles of X-ray production to spur ideation. Since more than 120 years, bremsstrahlung from X-ray tubes has been the workhorse of medical diagnostics. Generated by X-ray segments comprised of X-ray tubes and high-voltage generators in the various medical systems, X-ray photons in the spectral range between about 16 keV and 150 keV deliver information about anatomy and function of human patients and in pre-clinical animal studies. Despite of strides to employ the wave nature of X-rays as phase sensitive means, commercial diagnostic X-ray systems available until the time of writing still rely exclusively on measuring the attenuation and scattering of X-rays by matter. Significant activities in research aim at building highly brilliant short pulse X-ray sources, based on e.g. synchrotron radiation, free electron lasers and/or laser wake-field acceleration of electrons followed by wiggling with magnetic structures or Thomson scattering in bunches of light. While both approaches, non-brilliant and brilliant sources, have different scope of application, we speculate that a combination may expand the efficacy in medical application. At this point, however, severe technical and commercial difficulties hinder closing this gap. This article may inspire further development and spark innovation in this important field.
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Ion beam sputtering (IBS) can induce the formation of ordered nanostructures, whose properties depend on ion flux, sputtering angle, sample temperature, sample structure, surface symmetry, etc. For the comprehension of the time ev...
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Ion beam sputtering (IBS) can induce the formation of ordered nanostructures, whose properties depend on ion flux, sputtering angle, sample temperature, sample structure, surface symmetry, etc. For the comprehension of the time evolution of the formed nanostructure morphology it is necessary to perform in situ real time studies. In this review we shall describe results obtained using x-ray based techniques at synchrotron facilities to study in situ the time and temperature evolution of metal surfaces nanopatterned by ion sputtering. Different techniques, such as x-ray reflectivity, grazing incidence small angle x-ray scattering and x-ray surface diffraction have been used, each of them providing complementary information for the determination of the surface structure and morphology. In this review, we present some experiments done in recent years to show how these methods contributed to our understanding of the IBS process on metal surfaces.
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There are two beamlines (BLs), 4C1 and 4C2, at the Pohang Accelerator Laboratory that are dedicated to small angle X-ray scattering (S AXS). The 4C1 BL was constructed in early 2000 and is open to public users, including both dome...
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There are two beamlines (BLs), 4C1 and 4C2, at the Pohang Accelerator Laboratory that are dedicated to small angle X-ray scattering (S AXS). The 4C1 BL was constructed in early 2000 and is open to public users, including both domestic and foreign researchers. In 2003, construction of the second SAXS BL, 4C2, was complete and commissioning and user support were started. The 4C2 BL uses the same bending magnet as its light source as the 4C1 BL. The 4C1 BL uses a synthetic double multilayer, monochromator, whereas the 4C2 BL uses a Si(111) double crystal monochromator for both small angle and wide angle X-ray scattering. In the 4C2 BL, the collimating mirror is positioned behind the monochromator in order to enhance the beam flux and energy resolution. A toroidal focusing mirror is positioned in front of the monochromator to increase the beam flux and eliminate higher harmonics. The 4C2 BL also contains a digital cooled charge coupled detector, which has a wide dynamic range and good sensitivity to weak scattering, thereby making it suitable for a range of SAXS and wide angle X-ray scattering experiments. The general performance of the 4C2 BL was initially tested using standard samples and further confirmed by the experience of users during three years of operation. In addition, several grazing incidence X-ray scattering measurements were carried out at the 4C2BL.
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