Plane-grating flat-field soft x-ray spectrometer

Abstract

We describe a soft x-ray spectrometer covering the 120–800 eV range. It is intended for resonant inelastic x-ray scattering experiments performed at third generation synchrotron radiation (SR) facilities and has been developed with SOLEIL, the future French national SR source in mind. The Hettrick–Underwood principle is at the heart of the design using a combination of varied line-spacing plane grating and spherical-mirror to provide a flat-field image. It is slitless for optimum acceptance. This means the source size determines the resolving power. A spot size of ⩽5μm is planned at SOLEIL which, according to simulations, should ensure a resolving power ⩾1000 over the whole energy range. A 1024×1024 pixel charge-coupled device (CCD) with a 13μm×13μm pixel size is used. This is an improvement on the use of microchannel-plate detectors, both as concerns efficiency and spatial resolution. Additionally spectral line curvature is avoided by the use of a horizontal focusing mirror concentrating the beam in the nondispersing direction. It allows for readout using a binning mode to reduce the intrinsically large CCD readout noise. Preliminary results taken at beamlines at Elettra (Trieste) and at BESSY (Berlin) are presented.

Gaining efficiency and resolution in soft X-ray emission spectrometers thanks to directly illuminated CCD detectors

“…1 we show the optical scheme of our spectrometer, called advanced X-ray emission spectrograph (AXES) [6], currently installed at the beam line ID08 of the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. The general layout is shared by the majority of the soft X-ray spectrometers [7][8][9][10]: the radiation coming from the sample (illuminated by monochromatic X-ray beam) is dispersed in energy by the grating and a two-dimensional position sensitive detector allows the parallel acquisition of the emitted spectrum during periods of time of tens to hundreds of seconds. In some cases [10] one or two mirrors are also used to refocus the radiation before the detector, but this detail does not change the way the detector is used.…”

“…The general layout is shared by the majority of the soft X-ray spectrometers [7][8][9][10]: the radiation coming from the sample (illuminated by monochromatic X-ray beam) is dispersed in energy by the grating and a two-dimensional position sensitive detector allows the parallel acquisition of the emitted spectrum during periods of time of tens to hundreds of seconds. In some cases [10] one or two mirrors are also used to refocus the radiation before the detector, but this detail does not change the way the detector is used. During the acquisition everything remains fixed, included the incident photon energy.…”

Resonant X-ray emission spectroscopy of liquid water: Novel instrumentation, high resolution, and the “map” approach

“…While a variety of different new designs have been developed over the last few years [27][28][29][30][31], our VLS spectrometer exhibits a significantly higher transmission than current state-of-the-art spectrometers. A direct comparison with the permanently installed "SXF" spectrometer at Beamline 8.0 of the Advanced Light Source (ALS) [31] (note that this is an outstanding spectrometer with comparable spectral resolution, e.g., at the oxygen K edge [19]) showed an efficiency gain of about two orders of magnitude over the whole photon energy range.…”

High-resolution, high-transmission soft x-ray spectrometer for the study of biological samples

“…[1][2][3][4][5] ), we use a back-illuminated charge coupled device (CCD) detector from Andor Technology PLC. Comparable detectors were used in the instruments described in 8,10,11,17,18,20 . This choice, together with the optimized detector geometry (normal incidence compared to grazing incidence for Rowland circle spectrometers) increases the overall spectrometer efficiency further.…”

“…[1][2][3][4][5] ) are based on a grazing incidence spherical grating Rowland circle design 6 . Novel concepts often make use of variable line-space (VLS) gratings [7][8][9][10][11][12][13][14][15][16][17][18] . In order to enable XES/RIXS studies of organic and biological samples, we have designed a VLS spectrometer based on the work of Hettrick and Underwood [12][13][14][15][16] .…”