An alternative scheme of angular-dispersion analyzers for high-resolution medium-energy inelastic X-ray scattering

TL;DR

This paper analyzes the limitations of current angular-dispersion analyzers in high-resolution medium-energy inelastic X-ray scattering and proposes a simple four-bounce scheme to improve efficiency and feasibility.

Contribution

It introduces a novel four-bounce analyzer design that avoids multiple-beam diffraction and absorption effects, enhancing IXS spectroscopy resolution.

Findings

Multiple-beam diffraction reduces diffraction efficiency but is not fatal.

The four-bounce analyzer scheme effectively avoids adverse effects.

The new scheme is feasible for high-resolution IXS applications.

Abstract

The development of medium-energy inelastic X-ray scattering (IXS) optics with meV and sub-meV resolution has attracted considerable efforts in recent years. Meanwhile, there are also concerns or debates about the fundamental and feasibility of the involved schemes. Here the central optical component, the back-reflection angular-dispersion monochromator or analyzer, is analyzed. The results show that the multiple-beam diffraction effect together with transmission-induced absorption can noticeably reduce the diffraction efficiency, although it may not be a fatal threat. In order to improve the efficiency, a simple four-bounce analyzer is proposed that completely avoids these two adverse effects. The new scheme is illustrated to be a feasible alternative approach for developing meV- to sub-meV-resolution IXS spectroscopy.