Development and Implementation of Broadband Optical Pyrometry on the UC Davis 2-Stage Gas Gun

Characterization of the thermodynamic history of silicate minerals upon shock and release is critical for understanding and modeling planetary impact processes. Accurate equations of state, including off-Hugoniot states, require absolute temperature measurements to constrain phase boundaries and other properties that shape the outcomes of collisional processes. We have developed a suite of optical pyrometry tools that can be fielded simultaneously to observe broadband thermal emission over a wide temperature range. This includes a temporally and spectrally-resolved streaked spectrometer which operates between 350-850nm with ~nm spectral resolution and a six-channel visible/near-infrared pyrometry system extending from 650nm to 5000nm. Both systems are coupled to the sample via a single, custom fiber-optic probe, eliminating open optics and permitting a compact diagnostic footprint on the sample as well as portability of the system between our lab’s two light gas guns. In this presentation, we present details of the system’s construction, absolute calibration, and benchmark experiments on the melting curve of SiO₂ and (Mg,Fe)₂SiO₄ hugoniot.