A clean radiation environment for opacity measurements of radiatively heated material

Abstract

A clean x-ray radiation environment is essential for detailed measurements of the opacity of high-temperature radiatively heated material. A lot of laser energy is usually needed to heat a large hohlraum to produce such a clean x-ray radiation environment. A type of target is proposed that uses low-density, low-Z foam to provide a passage to radiation while isolating the sample from the disturbance from laser produced, high-temperature, high-Z plasma and heating by reflected laser light. With a smaller hohlraum, less laser energy is needed to produce high-temperature x-ray radiation for sample heating. Experiments have been done to check the proposal. The recorded clean Al self-emission spectra proved there was no gold plasma in the view-way to disturb the measurement. This type of hohlraum can provide a high-quality work-table for opacity measurement even in a relatively small laser facility.