Cryo scanning transmission X-ray microscope optimized for spectrotomography

TL;DR

This paper presents a cryo scanning transmission X-ray microscope optimized for spectrotomography, enabling high-resolution 3D chemical imaging of samples at cryogenic temperatures with improved data acquisition efficiency.

Contribution

The paper introduces a new cryo-STXM instrument capable of spectrotomography in the soft X-ray range with enhanced efficiency and resolution, suitable for detailed chemical and structural analysis.

Findings

Achieved 30 nm spatial resolution and 0.1 eV spectral resolution.

Demonstrated 3D tomograms and 4D chemical maps of fuel cell samples.

Enabled extended cryogenic imaging with minimal radiation damage.

Abstract

A cryo scanning transmission X-ray microscope, the cryo-STXM, has been designed and commissioned at the Canadian Light Source synchrotron. The instrument is designed to operate from 100 - 4000 eV (lambda = 12.4 - 0.31 nm). Users can insert a previously frozen sample, through a load lock, and rotate it plus minus 70 degrees in the beam to collect tomographic data sets. The sample can be maintained for extended periods at 92 K primarily to suppress radiation damage, and a pressure on the order of 10-9 Torr to suppress sample contamination. The achieved spatial resolution (30 nm) and spectral resolution (0.1 eV) are similar to other current soft X-ray STXMs, as demonstrated by measurements on known samples and test patterns. The data acquisition efficiency is significantly more favorable for both imaging and tomography. 2D images, 3D tomograms and 4D chemical maps of automotive hydrogen fuel cell thin sections are presented to demonstrate current performance and new capabilities, namely cryo-spectrotomography in the soft X-ray region.