A design of resonant inelastic X‐ray scattering (RIXS) spectrometer for spatial‐ and time‐resolved spectroscopy. (16th April 2020)

• Record Type: Journal Article
• Authors: Chuang, Yi-De; Feng, Xuefei; Glans-Suzuki, Per-Anders; Yang, Wanli; Padmore, Howard; Guo, Jinghua
• Is Part Of: Journal of synchrotron radiation. Volume 27:Part 3(2020)
• Page Start: 695
• Page End: 707
• Publication Date: 2020-04-16
• Subjects: Wolter type 1 mirrors -- soft X‐ray spectrometer -- resonant inelastic X‐ray scattering spectroscopy; Synchrotron radiation -- Periodicals; Free electron lasers -- Periodicals; 539.73505
• DOI: 10.1107/S1600577520004440
• Languages: English
• ISSNs: 0909-0495

Abstract

Abstract : The optical design of a soft X‐ray spectrometer that utilizes Wolter mirrors to enable imaging‐mode spectroscopy with a beam‐size independent spatial resolution in, for example, tandem catalysts in reaction is presented. When such a spectrometer is used in pump–probe experiments to study the transient electron dynamics, the imaging capability of the Wolter mirrors can offer femtosecond time delay between the pump and probe beams with non‐collinear wavefronts. Abstract : The optical design of a Hettrick–Underwood‐style soft X‐ray spectrometer with Wolter type 1 mirrors is presented. The spectrometer with a nominal length of 3.1 m can achieve a high resolving power (resolving power higher than 10000) in the soft X‐ray regime when a small source beam (<3 µm in the grating dispersion direction) and small pixel detector (5 µm effective pixel size) are used. Adding Wolter mirrors to the spectrometer before its dispersive elements can realize the spatial imaging capability, which finds applications in the spectroscopic studies of spatially dependent electronic structures in tandem catalysts, heterostructures, etc . In the pump–probe experiments where the pump beam perturbs the materials followed by the time‐delayed probe beam to reveal the transient evolution of electronic structures, the imaging capability of the Wolter mirrors can offer the pixel‐equivalent femtosecond time delay between the pump and probe beams when their wavefronts are not collinear. In combination with some special sample handing systems, such as liquid jets and droplets, the imaging capability can also be used to study the time‐dependent electronic structure of chemical transformation spanning multiple time domains from microseconds to nanoseconds. The proposed Wolter mirrors can also be adopted to the existing soft X‐ray spectrometers that use the Hettrick–Underwood optical scheme, expanding their capabilities in materials research.