Single-shot structural analysis by high-energy X-ray diffraction using an ultrashort all-optical source

Abstract

High-energy X-rays (HEX-rays) with photon energies on order of 100 keV have attractive characteristics, such as comparably low absorption, high spatial resolution and the ability to access inner-shell states of heavy atoms. These properties are advantageous for many applications ranging from studies of bulk materials to the investigation of materials in extreme conditions. Ultrafast X-ray diffraction allows the direct imaging of atomic dynamics simultaneously on its natural time and length scale. However, using HEX-rays for ultrafast studies has been limited due to the lack of sources that can generate pulses of sufficiently short (femtosecond) duration in this wavelength range. Here we show single-crystal diffraction using ultrashort ~90 keV HEX-ray pulses generated by an all-optical source based on inverse Compton scattering. We also demonstrate a method for measuring the crystal lattice spacing in a single shot that contains only ~105 photons in a spectral bandwidth of ~50% full width at half maximum (FWHM). Our approach allows us to obtain structural information from the full X-ray spectrum. As target we use a cylindrically bent Ge crystal in Laue transmission geometry. This experiment constitutes a first step towards measurements of ultrafast atomic dynamics using femtosecond HEX-ray pulses.

HEXITEC: A High-Energy X-ray Spectroscopic Imaging Detector for Synchrotron Applications

“…For the majority of experiments carried out at synchrotrons using the HEXITEC system, a pinhole camera setup has been used to provide geometric magnification. This technique has been applied to both X-ray florescence and X-ray diffraction imaging modalities as well as simultaneous measurements of both [2]- [4]. The following results are an example of a simple XRF measurement that was made as part of the setup and alignment of a HEXITEC system on the ID19 beamline at ESRF.…”

“…The system has been used at synchrotrons in applications which wish to discern mechanical, structural or chemical information from within thick samples or to determine the chemical composition of samples containing multiple high Z materials which, typically, have closely spaced K-line X-ray emissions. While originally developed for materials science applications [2], [3], the system has been successfully used across a diverse range of fields including pure science [4], [5], solar physics [6], medical imaging [7] and security applications [8]. This article will review the current status of the technology, the performance of the latest system and demonstrates the use of the system on a synchrotron beamline.…”

X-ray detector requirements for laser–plasma accelerators

“…Additionally, we include a dashed line at 1 count/px to indicate the relative threshold for single-photon spectroscopy techniques. Current detector systems, at reasonable distances (< 100 m), cannot operate in the single-photon mode in the direct beam, leading to secondary scattering techniques to utilise such detectors [65]. Reducing the pixel size can, in principle, work; however, this approach is fundamentally limited since the charge cloud, the energy deposition volume, and lateral diffusion through the substrate will start to dominate as the pixel size is reduced.…”