Here, a recently commissioned five-analyzer Johann spectrometer at the Inner Shell Spectroscopy beamline (8-ID) at the National Synchrotron Light Source II (NSLS-II) is presented. Designed for hard X-ray photon-in/photon-out spectroscopy, the spectrometer achieves a resolution in the 0.5-2 eV range, depending on the element and/or emission line, providing detailed insights into the local electronic and geometric structure of materials.
View Article and Find Full Text PDFJ Synchrotron Radiat
November 2024
Autonomous methods to align beamlines can decrease the amount of time spent on diagnostics, and also uncover better global optima leading to better beam quality. The alignment of these beamlines is a high-dimensional expensive-to-sample optimization problem involving the simultaneous treatment of many optical elements with correlated and nonlinear dynamics. Bayesian optimization is a strategy of efficient global optimization that has proved successful in similar regimes in a wide variety of beamline alignment applications, though it has typically been implemented for particular beamlines and optimization tasks.
View Article and Find Full Text PDFPhysical optics simulations for beamlines and experiments allow users to test experiment feasibility and optimize beamline settings ahead of beam time in order to optimize valuable beam time at synchrotron light sources like NSLS-II. Further, such simulations also help to develop and test experimental data processing methods and software in advance. The Synchrotron Radiation Workshop (SRW) software package supports such complex simulations.
View Article and Find Full Text PDFX-ray wavefront measurement is an important beam diagnostic tool, especially for the diffraction-limited X-ray beam. These in situ diagnostics give a better understanding of beam imperfections, and they enable feedback for possible corrections and/or optical alignment improvements. Hartmann wavefront sensing is one of the promising techniques to perform in situ X-ray wavefront measurements.
View Article and Find Full Text PDFThe Inner Shell Spectroscopy (ISS) beamline on the 8-ID station at the National Synchrotron Light Source II (NSLS-II), Upton, NY, USA, is a high-throughput X-ray absorption spectroscopy beamline designed for in situ, operando, and time-resolved material characterization using high monochromatic flux and scanning speed. This contribution discusses the technical specifications of the beamline in terms of optics, heat load management, monochromator motion control, and data acquisition and processing. Results of the beamline tests demonstrating the quality of the data obtainable on the instrument, possible energy scanning speeds, as well as long-term beamline stability are shown.
View Article and Find Full Text PDFSynchrotron X-ray footprinting (XF) is a growing structural biology technique that leverages radiation-induced chemical modifications via X-ray radiolysis of water to produce hydroxyl radicals that probe changes in macromolecular structure and dynamics in solution states of interest. The X-ray Footprinting of Biological Materials (XFP) beamline at the National Synchrotron Light Source II provides the structural biology community with access to instrumentation and expert support in the XF method, and is also a platform for development of new technological capabilities in this field. The design and implementation of a new high-throughput endstation device based around use of a 96-well PCR plate form factor and supporting diagnostic instrumentation for synchrotron XF is described.
View Article and Find Full Text PDFJ Synchrotron Radiat
July 2021
During the COVID-19 pandemic, synchrotron beamlines were forced to limit user access. Performing routine measurements became a challenge. At the Life Science X-ray Scattering (LiX) beamline, new instrumentation and mail-in protocols have been developed to remove the access barrier to solution scattering measurements.
View Article and Find Full Text PDFBackground: We introduced a video consultation (VC) during the coronavirus (COVID-19) pandemic in an ophthalmology practice with eight doctors to ensure continuous ophthalmological care, infection prophylaxis and to compensate a decreased number of patient presentations.
Objective: Evaluation of the most common reasons for patient presentations in the VC, the proportion of re-presentations in the practice despite VC, practical challenges associated with the introduction of VC and patient satisfaction.
Material And Methods: Patients with a recent acute visual deterioration and severe eye pain were excluded from the VC.
Background: Results from recent studies show that less intravitreal injections are often performed in everyday practice than in controlled trials, which subsequently leads to worse treatment success. In this study we analyzed the introduction of a more stringent organization of treatment using workflow optimization and new IT systems and analyzed the effect on treatment continuity.
Material And Methods: In the second quarter of 2019 a new medical practice management software and a software for automated injection planning were implemented.
Background: We introduced a video consultation (VC) during the coronavirus (COVID-19) pandemic in an ophthalmology practice with eight doctors to ensure continuous ophthalmological care, infection prophylaxis and to compensate a decreased number of patient presentations.
Objective: Evaluation of the most common reasons for patient presentations in the VC, the proportion of re-presentations in the practice despite VC, practical challenges associated with the introduction of VC and patient satisfaction.
Material And Methods: Patients with a recent acute visual deterioration and severe eye pain were excluded from the VC.
Sirepo, a browser-based GUI for X-ray source and optics simulations, is presented. Such calculations can be performed using SRW (Synchrotron Radiation Workshop), which is a physical optics computer code, allowing simulation of entire experimental beamlines using the concept of a `virtual beamline' with accurate treatment of synchrotron radiation generation and propagation through the X-ray optical system. SRW is interfaced with Sirepo by means of a Python application programming interface.
View Article and Find Full Text PDFNovel features of the longitudinal instability of a single electron bunch circulating in a low-emittance electron storage ring are discussed. Measurements and numerical simulations, performed both in time and frequency domain, show a non-monotonic increase of the electron beam energy spread as a function of single bunch current, characterized by the presence of local minima and maxima, where a local minimum of the energy spread is interpreted as a higher-order microwave instability threshold. It is also shown that thresholds related to the same zero-intensity bunch length depend linearly on the accelerating radio frequency voltage.
View Article and Find Full Text PDFWith the motivation of searching for new superconductors in the Mg-B system, we performed ab initio evolutionary searches for all the stable compounds in this binary system in the pressure range of 0-200 GPa. We found previously unknown, yet thermodynamically stable, compositions MgB and MgB. Experimentally known MgB is stable in the entire pressure range 0-200 GPa, while MgB and MgB are stable at pressures below 90 GPa and 35 GPa, respectively.
View Article and Find Full Text PDFWith the motivation of discovering high-temperature superconductors, evolutionary algorithm USPEX is employed to search for all stable compounds in the Sn-H system. In addition to the traditional SnH4, new hydrides SnH8, SnH12 and SnH14 are found to be thermodynamically stable at high pressure. Dynamical stability and superconductivity of tin hydrides are systematically investigated.
View Article and Find Full Text PDFA previously unknown thermodynamically stable high-pressure phase of BeF2 has been predicted using the evolutionary algorithm USPEX. This phase occurs in the pressure range 18-27 GPa. Its structure has C2/c space group symmetry and contains 18 atoms in the primitive unit cell.
View Article and Find Full Text PDFA study covering 277 psychopathic patients has been aimed at specifying the notion of psychopathy as well as the criteria of its diagnosis with the help of follow-up findings. Psychopathies are considered as a transient status of protracted adaptation due to retardation of the pubertal period. The study of "true" psychopathy has demonstrated that psychic disturbances are transitory and determined typologically by manifestations of neurosis or neurotic development.
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