Application of a transmission crystal x-ray spectrometer to moderate-intensity laser driven sources

Abstract

In the pursuit of novel, laser-produced x-ray sources for medical imaging applications, appropriate instrumental diagnostics need to be developed concurrently. A type of transmission crystal spectroscopy has previously been demonstrated as a survey tool for sources produced by high-power and high-energy lasers. The present work demonstrates the extension of this method into the study of medium-intensity laser driven hard x-ray sources with a design that preserves resolving power while maintaining high sensitivity. Specifically, spectroscopic measurements of characteristic Kα and Kβ emissions were studied from Mo targets irradiated by a 100 fs, 200 mJ, Ti: sapphire laser with intensity of 10(17) W/cm(2) to 10(18) W∕cm(2) per shot. Using a transmission curved crystal spectrometer and off-Rowland circle imaging, resolving powers (E/ΔE) of around 300 for Mo Kα(2) at 17.37 keV were obtained with an end-to-end spectrometer efficiency of (1.13 ± 0.10) × 10(-5). This sensitivity is sufficient for registering x-ray lines with high signal to background from targets following irradiation by a single laser pulse, demonstrating the utility of this method in the study of the development of medium-intensity laser driven x-ray sources.