Energy-Dispersive X-ray Absorption Spectroscopy with an Inverse Compton Source

Juanjuan Huang,Martin Dierolf,Bernhard Gleich,Yi-Tao Cui,Franz Pfeiffer,Benedikt Günther,Klaus Achterhold

doi:10.1038/s41598-020-65225-4

Abstract

Novel compact x-ray sources based on inverse Compton scattering can generate brilliant hard x-rays in a laboratory setting. Their collimated intense beams with tunable well-defined x-ray energies make them well suited for x-ray spectroscopy techniques, which are typically carried out at large facilities. Here, we demonstrate a first x-ray absorption spectroscopy proof-of-principle experiment using an inverse Compton x-ray source with a flux of >1010 photons/s in <5% bandwidth. We measured x-ray absorption near edge structure and extended x-ray absorption fine structure at the silver K-edge (~25.5 keV) for a series of silver samples. We propose an energy-dispersive geometry specifically adapted to the x-ray beam properties of inverse Compton x-ray sources together with a fast concentration correction method that corrects sample inhomogeneities very effectively. The combination of our setup with the inverse Compton source generates x-ray absorption spectra with high energy resolution in exposure times down to one minute. Our results unravel the great benefit of inverse Compton scattering sources for x-ray absorption techniques in a laboratory environment, especially in the hard x-ray regime, which allows to probe absorption edges of high Z materials.

Highlights

X-ray absorption spectroscopy (XAS) is an element-selective spectroscopic method which can probe the chemical surroundings around an atom of interest
The limited access to and high cost of large-scale synchrotron facilities inhibit the wide-spread use of XAS as part of standard laboratory workflows on a daily basis. These days the performance of XAS implemented with x-ray tubes has greatly improved[5,6,7], the low brilliance when using bremsstrahlung results in long acquisition times, restricting its applications to only a few certain samples and research subjects. This limitation can be overcome by recent developments in novel compact x-ray sources based on laserproduced plasma (LPP)[8], high-harmonic generation (HHG)[9,10], betatron radiation[11] or inverse Compton scattering[12,13,14]
We carried out x-ray absorption near-edge structure (XANES) and extended x-ray absorption fine structure (EXAFS) measurements at the silver K-edge with a series of different silver compounds, which yield spectra with a quality comparable to synchrotron data

Summary

Introduction

X-ray absorption spectroscopy (XAS) is an element-selective spectroscopic method which can probe the chemical surroundings around an atom of interest. The limited access to and high cost of large-scale synchrotron facilities inhibit the wide-spread use of XAS as part of standard laboratory workflows on a daily basis These days the performance of XAS implemented with x-ray tubes has greatly improved[5,6,7], the low brilliance when using bremsstrahlung results in long acquisition times, restricting its applications to only a few certain samples and research subjects. This limitation can be overcome by recent developments in novel compact x-ray sources based on laserproduced plasma (LPP)[8], high-harmonic generation (HHG)[9,10], betatron radiation[11] or inverse Compton scattering ( called Thomson scattering)[12,13,14]. This facilitates the measurement of inhomogeneous samples such as a typical XAS pellet, which is very difficult to handle both at synchrotrons and in laboratories using energy-dispersive geometries[6,33]

Methods

Results

Conclusion