Enhanced X-Ray Angular Dispersion and X-ray Spectrographs with Resolving Power Beyond 10$^{8}$

TL;DR

This paper demonstrates that multi-crystal x-ray optics can achieve extremely high angular dispersion rates, enabling the development of high-resolution x-ray spectrographs with resolving power exceeding 10^8.

Contribution

The study introduces a multi-crystal arrangement approach that significantly enhances angular dispersion rates, making ultra-high-resolution x-ray spectrographs feasible.

Findings

Multi-crystal arrangements yield over tenfold increase in angular dispersion rates.

Hard x-ray spectrographs with resolving power beyond 10^8 are achievable.

Potential for faster, more precise x-ray spectral analysis.

Abstract

Spectrograph is an optical device that is used to disperse photons of different energies $E$ into distinct directions and space locations, and to take a snapshot of the whole spectrum of photon energies with a spatially sensitive photon detector. Substantial advantage of a spectrograph over an ordinary spectral analyzer, is its ability to deal with many photon energies simultaneously, thus reducing exposure time per spectrum considerably. To realize a spectrograph, dispersing elements with large angular dispersion rate are required. Here we show, on the example of CDW x-ray optics [1-3], that multi-crystal arrangements may feature cumulative angular dispersion rates more than an order of magnitude larger than those attainable in single Bragg reflections. This makes, first, hard x-ray spectrographs feasible, and, secondly, a resolving power beyond $E/\Delta E \gtrsim 10^{8}$ achievable.