A Compact Dispersive Refocusing Rowland Circle X-ray Emission Spectrometer for Laboratory, Synchrotron, and XFEL Applications

TL;DR

This paper introduces a compact, high-resolution dispersive refocusing Rowland circle x-ray emission spectrometer suitable for laboratory and large-scale x-ray facilities, enabling efficient electronic state analysis with portability and high count rates.

Contribution

The design of a compact, portable x-ray emission spectrometer with high energy resolution using a dispersive refocusing Rowland geometry for 2-2.5 keV applications.

Findings

Achieves high energy resolution for unfocused x-ray sources.

Provides high count rates comparable to synchrotron beamlines.

Demonstrates higher efficiency than previous systems.

Abstract

X-ray emission spectroscopy is emerging as an important complement to x-ray absorption fine structure spectroscopy, providing a characterization of the occupied electronic density of states local to the species of interest. Here, we present details of the design and performance of a compact x-ray emission spectrometer that uses a dispersive refocusing Rowland (DRR) circle geometry to achieve excellent performance for the 2 - 2.5 keV energy range. The DRR approach allows high energy resolution even for unfocused x-ray sources. This property enables high count rates in laboratory studies, comparable to those of insertion-device beamlines at third-generation synchrotrons, despite use of only a low-powered, conventional x-ray tube. The spectrometer, whose overall scale is set by use of a 10-cm diameter Rowland circle and a new small-pixel CMOS x-ray camera, is easily portable to synchrotron or x-ray free electron beamlines. Photometrics from measurements at the Advanced Light Source show somewhat higher overall instrumental efficiency than prior systems based on less tightly curved analyzer optics. In addition, the compact size of this instrument lends itself to future multiplexing to gain large factors in net collection efficiency, or its implementation in controlled gas gloveboxes either in the lab or in an endstation.