Simultaneous Raman And Pyrometric Temperature Measurements In Shock-Wave-Compressed Toluene

We fielded experiments to compare temperatures measured simultaneously by pyrometry and Raman spectroscopy in toluene shocked to 9GPa. A 0.5mm thick toluene sample was compressed between sapphire windows by plate impact from a gas gun. As the shock wave reverberated between the windows, the pressure increased stepwise to about 9GPa. While the sample was near its peak pressure, we measured the Raman spectrum and determined temperature from the ratio of the Stokes and anti-Stokes intensities. Simultaneously, we measured the sample thermal radiance from the C-H vibration bands that occur between 3.2 and 3.6m to determine temperature pyrometrically. The pyrometer used a biased indium antimonide detector paired with a custom transimpedance amplifier, a system capable of temperature measurements as low as about 400K. The Raman measurements gave a temperature of 530 +/- 25K in the bulk volume of toluene. Pyrometry gave a temperature of 496+15/-20K, which is in reasonable agreement with the Raman measurement. Comparisons of this type are necessary to validate pyrometry as a temperature diagnostic in dynamic experiments.