High-resolution X-ray emission spectroscopy with transition-edge sensors: present performance and future potential

Abstract

X-ray emission spectroscopy (XES) is a powerful element-selective tool to analyze the oxidation states of atoms in complex compounds, determine their electronic configuration, and identify unknown compounds in challenging environments. Until now the low efficiency of wavelength-dispersive X-ray spectrometer technology has limited the use of XES, especially in combination with weaker laboratory X-ray sources. More efficient energy-dispersive detectors have either insufficient energy resolution because of the statistical limits described by Fano or too low counting rates to be of practical use. This paper updates an approach to high-resolution X-ray emission spectroscopy that uses a microcalorimeter detector array of superconducting transition-edge sensors (TESs). TES arrays are discussed and compared with conventional methods, and shown under which circumstances they are superior. It is also shown that a TES array can be integrated into a table-top time-resolved X-ray source and a soft X-ray synchrotron beamline to perform emission spectroscopy with good chemical sensitivity over a very wide range of energies.

Ultrafast Time-Resolved Hard X-Ray Emission Spectroscopy on a Tabletop

“…Additional details are given in Sec. IV C. The combination of a laser plasma source and microcalorimeter array has previously been proposed for time-resolved absorption spectroscopy [39] and used to obtain static absorption and emission spectra [31,32,34,39], but the results we present here are the first demonstration of time-resolved x-ray spectroscopy with this approach.…”

“…TRXES experiments with time resolution better than 60 ps have been performed only at the LCLS and SACLA free-electron laser facilities where sub-100-fs resolution is possible [7,[25][26][27][28]. In the laboratory, static XES measurements are possible [29][30][31][32], but measurements of ultrafast behavior have been stymied by the limited intensity of laboratory x-ray sources with suitable pulse duration and the limited collection efficiency of high-resolution x-ray spectrometers.…”

“…Only 70% of the x rays delivered to the sample in our experiment have sufficient It is useful to compare the factor of 660 advantage in photon collecting efficiency determined above to firstprinciples estimates based on detector properties such as solid angle and detection probability. Uhlig et al [32] performed a detailed comparison between microcalorimeter arrays and wavelength-dispersive spectrometers like the ones currently used at synchrotron and free-electron laser facilities. In this analysis, the x-ray collecting efficiency of a microcalorimeter array similar to the one we use here was estimated to be 170 and 730 times larger than two modern spectrometers with 16 and 5 dispersive crystals, respectively.…”

Beating Darwin-Bragg losses in lab-based ultrafast x-ray experiments

“…As with semiconductor detectors, X-ray emission examinations have an extended history in the development of X-ray microcalorimeters, 77,111 yet demonstrations using fast ions 139,171 and at chemical resolution using lab-based femtosecond laser-driven X-rays 142,172 are now greatly expanding the prospects. Resonant inelastic X-ray scattering (RIXS) measurements 161,173 are also a potential target.…”

Microcalorimeters for X-Ray Spectroscopy of Highly Charged Ions at Storage Rings

“…In terms of detection efficiency, this feature places microcalorimeters between germanium detectors with their large active detector areas and crystal spectrometers with their rather small angular acceptance. In [33], Uhlig et al have given an extensive comparison of microcalorimeters and crystal spectrometers with respect to energy resolution and detection efficiency. Although the discussion focuses on X-ray energies below 10 keV, the same arguments apply for microcalorimeters for high X-ray energies as presented here.…”