An etched multilayer as a dispersive element in a curved-crystal spectrometer: implementation and performance

TL;DR

This paper presents the development and implementation of an etched multilayer dispersive element in a curved-crystal spectrometer, significantly enhancing spectral resolution for soft x-ray emission spectroscopy.

Contribution

It introduces a novel fabrication process for etched multilayers, demonstrating improved spectral resolution in a Johann-type spectrometer for chemical state analysis.

Findings

Diffraction pattern narrows by a factor of 4 compared to non-etched structures

Enhanced spectral resolution enables distinction of chemical states of carbon

Successful implementation in high-resolution x-ray emission spectroscopy

Abstract

Etched multilayers obtained by forming a laminar grating pattern within interferential multilayer mirrors are used in the soft x-ray range to improve the spectral resolution of wavelength dispersive spectrometers equipped with periodic multilayers. We describe the fabrication process of such an etched multilayer dispersive element, its characterization through reflectivity measurement and simulations, and its implementation in a high-resolution Johann-type spectrometer. The specially designed patterning of a Mo/B4C multilayer is found fruitful in the range of the C K emission as the diffraction pattern narrows by a factor 4 with respect to the non-etched structure. This dispersive element with an improved spectral resolution was successfully implemented for electronic structure study with an improved spectral resolution by x-ray emission spectroscopy. As first results we present the distinction between the chemical states of carbon atoms in various compounds, such as graphite, SiC and B4C, by the different shape of their C K emission band.