X-ray transmission measurements of high-temperature Al plasma by using Z-pinch dynamic hohlraum on 10 MA facility

Abstract

Measurements of x-ray transmission in a high-temperature Al plasma over the 1.4–2.1 keV photon energy range are reported, which is driven by axial x-ray radiation from Z-pinch–driven dynamic hohlraum on 10 MA facility in China. Two identical bent convex cylindrical KAP crystal spectrometers are deployed at ±8° along two directions, enabling simultaneous acquisition of the absorption spectrum and the radiation source spectrum from a ‘half-moon’ target within a single shot. The x-ray transmission is subsequently obtained by taking the ratio of these two spectra. By comparing the experimental transmission with calculated results, the radiatively heated Al plasma is inferred to reach a temperature of ∼122 eV and an electron density of ∼1.1 × 1022 cm−3. In addition, a time-resolved diagnostic system based on an elliptical concave KAP crystal spectrometer with a temporal resolution of 1.3 ns has been developed to measure the x-ray spectra of the sample plasma at different times. Compared with time-integrated measurements, the signal-to-noise ratio is significantly improved, enabling the observation of Al plasma spectra at temperature below 100 eV.