Pyrometric Measurement of the Temperature of Shocked Molybdenum

TL;DR

This study uses pyrometry and continuum dynamics modeling to accurately measure the temperature of shocked molybdenum, accounting for window contributions and revealing detailed thermal behavior during shock and release.

Contribution

It introduces a method to separate sample temperature from window effects in pyrometry measurements of shocked materials.

Findings

Shock-and release temperature of Mo was 762±40K.

LiF window shows non-thermal radiance with a bulk temperature of 624±112K.

Hot spots within the window reach about 2000K.

Abstract

Measurements of the temperature of Mo shocked to ~60 GPa and then released to ~28 GPa were previously attempted using high explosive driven flyer plates and pyrometry. Analysis of the radiance traces at different wavelengths indicates that the temporal evolution of the radiance can be explained by a contribution from the LiF window to the measured thermal radiation. Fitting the radiance traces with a simple model, supported by continuum dynamics studies which were able to relate structures in the radiance history to hydrodynamic events in the experiment, the contribution of the window was obtained and hence the temperature of the Mo sample. The shock-and release temperature obtained in the Mo was 762+/-40K which is consistent with calculations taking the contribution of plastic work to the heating into account. The radiance obtained for the LiF window shows a non thermal distribution which can be described by a bulk temperature of 624+/-112K and hot spots (less than 0.5% in total volume) within the window at a temperature of about 2000K.