Femtosecond Thermal Diffuse Scattering from Laser-Shocked Tantalum

Measurements of the absolute intensity of the Thermal Diffuse Scattering (TDS) in shocked copper have recently been used to obtain single-shot femtosecond measurements of the temperature along the Hugoniot [J.S. Wark et al, arXiv:2501.02940 (2025)]. Excellent agreement was found between the experimental data and classic TDS models presented by Warren, which allowed direct measurements of the Debye-Waller (DW) factor. This, in combination with an assumed Debye temperature at each compression, can provide a temperature measurement. For the case of copper it was found that the TDS intensity is insensitive to the texture of our target, this is not the case for the elastic Bragg peaks. Here we present similar analysis the BCC metal tantalum. These experiments were performed at the High Energy Density (HED) endstation of the European X-Ray Free-Electron-Laser (EuXFEL). Targets were laser shocked with the DiPOLE 100-X laser, with simultaneous 50fs 18keV x-ray pulses projecting azimuthally resolved x-ray diffraction on two VAREX detectors. The TDS signal is sufficiently large that, with consideration of Compton scattering, and elastic scattering from th ablator material, its absolute intensity can be measured relative to the intensity of the x-ray beam.