Hard x ray spectroscopy and imaging by a reflection zone plate in the presence of astigmatism

The feasibility of an off axis x ray reflection zone plate to perform wavelength dispersive spectroscopy, on axis point focusing, and two dimensional imaging is demonstrated by means of one and the same diffractive optical element DOE at a synchrotron radiation facility. The resolving power varies between 30 and 400 in the range of 7.6 keV to 9.0 keV, with its maximum at the design energy of 8.3 keV. This result is verified using an adjustable entrance slit, by which horizontal H and vertical V focusing to 0.85 amp; 956;m H and 1.29 amp; 956;m V is obtained near the sagittal focal plane of the astigmatic configuration. An angular and axial scan proves an accessible field of view of at least 0.6 arcmin 0.8 arcmin and a focal depth of plus minus 0.86 mm. Supported by the grating efficiency of around 17.5 and a very short pulse elongation, future precision x ray fluorescence and absorption studies of transition metals at their K edge on an ultrashort timescale could benefit from our finding

Highly efficient soft X ray spectrometer based on a reflection zone plate for resonant inelastic X ray scattering measurements

We present a newly designed compact and flexible soft X-ray spectrometer for resonant inelastic X-ray scattering (RIXS) studies within an energy range from 380 eV to 410 eV, which would include the K alpha emission lines of vital elements like nitrogen. We utilized an off-axis reflection zone plate (RZP) as the wavelength selective element with a maximum line density of 10000 l/mm. A higher energy resolution over a broader range of +/- 15 eV around the designed energy was achieved by displacing the RZP. Additionally, for the first time, an actual optical side effect, the so-called comatic aberration was exploited to increase the energy resolution. First results show a resolving power in the order of 1300 for photon energy of 395 eV, which is comparable to a commercial varied line spacing grating (VLS)

The hard X-ray Photon Single-Shot Spectrometer of SwissFEL - Initial characterization

SwissFEL requires the monitoring of the photon spectral distribution at a repetition rate of 100 Hz for machine optimization and experiment online diagnostics. The Photon Single Shot Spectrometer has been designed for the photon energy range of 4 keV to 12 keV provided by the Aramis beamline. It is capable of measuring the spectrum in a non-destructive manner, with an energy resolution of Δ E/E = (2-5) × 10-5 over a bandwidth of 0.5% on a shot-to-shot basis. This article gives a detailed description about the technical challenges, structures, and considerations when building such a device, and to further enhance the performance of the spectrometer

X ray absorption spectroscopy using a self seeded soft X ray free electron laser

X ray free electron lasers XFELs enable unprecedented new ways to study the electronic structure and dynamics of transition metal systems. L edge absorption spectroscopy is a powerful technique for such studies and the feasibility of this method at XFELs for solutions and solids has been demonstrated. However, the required x ray bandwidth is an order of magnitude narrower than that of self amplified spontaneous emission SASE , and additional monochromatization is needed. Here we compare L edge x ray absorption spectroscopy XAS of a prototypical transition metal system based on monochromatizing the SASE radiation of the linac coherent light source LCLS with a new technique based on self seeding of LCLS. We demonstrate how L edge XAS can be performed using the self seeding scheme without the need of an additional beam line monochromator. We show how the spectral shape and pulse energy depend on the undulator setup and how this affects the x ray spectroscopy measurement

A compact and cost-effective hard X-ray free-electron laser driven by a high-brightness and low-energy electron beam

We present the first lasing results of SwissFEL, a hard X-ray free-electron laser (FEL) that recently came into operation at the Paul Scherrer Institute in Switzerland. SwissFEL is a very stable, compact and cost-effective X-ray FEL facility driven by a low-energy and ultra-low-emittance electron beam travelling through short-period undulators. It delivers stable hard X-ray FEL radiation at 1-Å wavelength with pulse energies of more than 500 μJ, pulse durations of ~30 fs (root mean square) and spectral bandwidth below the per-mil level. Using special configurations, we have produced pulses shorter than 1 fs and, in a different set-up, broadband radiation with an unprecedented bandwidth of ~2%. The extremely small emittance demonstrated at SwissFEL paves the way for even more compact and affordable hard X-ray FELs, potentially boosting the number of facilities worldwide and thereby expanding the population of the scientific community that has access to X-ray FEL radiation

Annual (2023) taxonomic update of RNA-directed RNA polymerase-encoding negative-sense RNA viruses (realm Riboviria: kingdom Orthornavirae: phylum Negarnaviricota)

55 Pág.In April 2023, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote on newly proposed taxa, the phylum Negarnaviricota was amended and emended. The phylum was expanded by one new family, 14 new genera, and 140 new species. Two genera and 538 species were renamed. One species was moved, and four were abolished. This article presents the updated taxonomy of Negarnaviricota as now accepted by the ICTV.This work was supported in part through the Laulima Government Solutions, LLC, prime contract with the U.S. National Institute of Allergy and Infec tious Diseases (NIAID) under Contract No. HHSN272201800013C. J.H.K. performed this work as an employee of Tunnell Government Services (TGS), a subcontractor of Laulima Government Solutions, LLC, under Contract No. HHSN272201800013C. U.J.B. was supported by the Division of Intramural Resarch, NIAID. This work was also funded in part by Contract No. HSHQDC15-C-00064 awarded by DHS S and T for the management and operation of The National Biodefense Analysis and Countermeasures Centre, a federally funded research and development centre operated by the Battelle National Biodefense Institute (V.W.); and NIH contract HHSN272201000040I/HHSN27200004/D04 and grant R24AI120942 (N.V., R.B.T.). S.S. acknowl edges support from the Mississippi Agricultural and Forestry Experiment Station (MAFES), USDA-ARS project 58-6066-9-033 and the National Institute of Food and Agriculture, U.S. Department of Agriculture, Hatch Project, under Accession Number 1021494. The funders had no role in the design of the study; in the collection, analysis, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Department of the Army, the U.S. Department of Defence, the U.S. Department of Health and Human Services, including the Centres for Disease Control and Prevention, the U.S. Department of Homeland Security (DHS) Science and Technology Directorate (S and T), or of the institutions and companies affiliated with the authors. In no event shall any of these entities have any responsibility or liability for any use, misuse, inability to use, or reliance upon the information contained herein. The U.S. departments do not endorse any products or commercial services mentioned in this publication. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S.Government retains a non-exclusive, paid up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for U.S. Government purposes.Peer reviewe

Hydrocarbon habitat of the Paleogene Nesvacilka Trough, Carpathian foreland basin, Czech Republic

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A case study of novel X-ray Optics for FEL sources

We suggest optical schemes for the European X-ray Free Electron Laser facility (XFEL.EU) in Hamburg: a single element X-ray spectrometer on the basis of a reflection zone plate (RZP) for single-shot diagnostics; and a two-element soft X-ray spectrometer on the basis of two RZPs to carry out Resonant Inelastic X-ray Scattering (RIXS) experiments. With this setup, a full map of the sample spectrum is obtainable in a single measurement. The main advantage of using zone plates is the possibility to enable dispersion and focusing in one step. Moreover, highest possible X-ray transmission is achieved by using the minimum number of optical elements. Taking into account the European XFEL beam parameters, our simulations, concerning the RIXS experiment, produced very promising results, reaching an energy resolution (E/ΔE) of up to 30,000 at photon energy of 1 keV. When applied as a single shot spectrometer the energy resolution for RZP is of the same order of magnitude