Dynamic radiance measurements at HEAF’s two-stage large gas gun

Collaborators from LLNL's shock physics group, JASPER, and NSTec conducted a series of experiments in September at the two-stage large gas gun in HEAF that involved the fielding of three new seven-channel pyrometry systems for measuring dynamic radiance. Radiance measurements are a critical step toward developing high-accuracy temperature measurements, which will enable significantly improved equation-of-state measurements and calculations in support of LLNL's Stockpile Stewardship Program . These systems, built by NSTec, have extended spectral coverage, spanning 350 nm to 1.3 μm, as well as improved detectors for better sensitivity and nanosecond time resolution. All three pyrometers successfully recorded the radiance from shocked water targets, completing LLNL's acceptance tests and satisfying a joint LLNL-NSTec FY14 L2 milestone. Future experiments will incorporate these pyrometry systems into full temperature measurements of dynamically compressed materials both at HEAF and ultimately at JASPER.