Coherent anti-Stokes Raman Spectroscopy and pyrometry for temperature measurement in ejecta

We demonstrate the use of Coherent Anti-Stokes Raman Spectroscopy (CARS) and pyrometry to measure temperature in dynamically compressed gases (D2, H2) and ejecta. CARS temperature measurements in pure gases (no ejecta present) are compared to predictions from basic 1-D shock theory which is found to accurately predict the break out properties of the gas shock, though in shocks driven by high explosives significant cooling can occur after breakout that is not accounted for in 1-D models. The gas temperature measurements were made to determine the ambient conditions for ejecta. Pyrometry was also used to measure the temperature of the ejecta. Time-resolved pyrometry measurements of ejecta in these gases show that temperature and emissivity tend to stabilize on a microsecond timescale and equilibrate to temperatures near that expected of the pure gas, except in cases where the metal ejecta is known to chemically react with the gas, in which case ejecta temperature appears hotter than the gas alone would be.