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Several high priority subjects in astrophysics can be addressed by a state-of-the-art soft x-ray grating spectrometer (XGS). An Explorer-scale, large-area (> 1,000 cm2), high resolving power (R > 3,000) XGS is highly feasible based on Critical-Angle Transmission (CAT) gratings, even for telescopes with angular resolution of 5-10 arcsec. Significantly higher performance can be provided by a CAT XGS on an X-ray-Surveyor-type mission. CAT gratings combine the advantages of blazed reflection gratings (high efficiency, use of higher diffraction orders) with those of transmission gratings (low mass, relaxed alignment and temperature requirements, transparent at high energies) with minimal mission resource demands. They are high-efficiency blazed transmission gratings that consist of freestanding, ultra-high aspect-ratio grating bars made from SOI wafers using anisotropic dry and wet etch techniques. Blazing is achieved through reflection off grating bar sidewalls. Silicon is well matched to the soft x-ray band, and existing silicon CAT gratings exceed 30% absolute diffraction efficiency, with clear paths for improvement. CAT gratings coated with heavier elements allow extension of the CAT grating principle to higher energies and larger angles, enabling higher resolving power at shorter wavelengths. We show x-ray data from CAT gratings coated with platinum using atomic layer deposition, and demonstrate blazing to higher energies and much larger blaze angles than possible with silicon. We measure resolving power of a CAT XGS consisting of a Wolter-I focusing mirror pair from GSFC and CAT gratings, performed at the MSFC SLF. Measurement of the Al Ka doublet in 18th order shows resolving power > 10,000, based on preliminary analysis. This demonstrates that currently fabricated CAT gratings are compatible with the most advanced XGS designs for future soft x-ray spectroscopy missions.
We present measurements of the resolving power of a soft x-ray spectrometer consisting of 200 nm-period lightweight, alignment-insensitive critical-angle transmission (CAT) gratings and a lightweight slumped-glass Wolter-I focusing mirror pair. We me
High-resolution ($R = lambda /Delta lambda > 2000$) x-ray absorption and emission line spectroscopy in the soft x-ray band is a crucial diagnostic for the exploration of the properties of ubiquitous warm and hot plasmas and their dynamics in the cosm
The Mid-Infrared Instrument (MIRI) on-board JWST will provide imaging, coronagraphy, low-resolution spectroscopy and medium-resolution spectroscopy at unprecedented sensitivity levels in the mid-infrared wavelength range. The Medium-Resolution Spectr
A new type of hemispherical electron energy analyzer that permits angle and spin resolved photoelectron spectroscopy has been developed. The analyzer permits standard angle resolved spectra to be recorded with a two-dimensional detector in parallel w
We present the first X-ray spectrum obtained by the Low Energy Transmission Grating Spectrometer (LETGS) aboard the Chandra X-ray Observatory. The spectrum is of Capella and covers a wavelength range of 5-175 A (2.5-0.07 keV). The measured wavelength