Analysis of temperature measurement at material/LiF interface under moderate shock wave compression

Abstract
In the field of dynamic high-pressure physics of condensed materials, the accurate knowledge of the thermodynamic state of a material is fundamental to understand its dynamic behaviour under stress. The equation of state of materials is verified in terms of pressure, density and internal energy thanks to the measurements of pressure and velocity under shock wave compression with a satisfying precision. The theoretical temperature evaluated from EOS remains discussed. So; its accurate measurement is of great interest, in particular at low temperature. However, in this range, measurements appear more difficult to perform. Because of this, a high-speed infrared three-wavelength pyrometer has been modified at CEG to perform measurements at very low temperature (<500 K). Besides, an emissive layer has been designed to increase the emissivity of the shocked surface. To reduce the uncertainty of the temperature measurement, it appears necessary to limit its emissivity to a 0.9–1 range.