Measurement of hard x-rays at a staged Z-pinch using a 128-channel scintillator array

Z-pinch plasmas capable of sustaining nuclear fusion also generate X-rays with energies exceeding 5 keV. These X-rays can be generated by three different sources: the high average kinetic energy in the plasma, energetic particle beams, and as a secondary byproduct of fusion products scattering off of the environment. Each of these sources has characteristic spectra, timing, and origin, and their presence can be used to assess the suitability of a fusion concept for thermonuclear fusion. A scintillator-based, 128-channel, portable hard X-ray detector array with 40 ns time response has been built and deployed as one of ARPA-E’s fusion diagnostic capability teams. This array has been used to measure the hard X-rays from the staged Z-pinch driven by UCSD’s CESZAR linear transformer driver. The array has operated in three modes: a detector mode to correlate X-ray production with neutrons, a pinhole imaging mode to determine the X-ray origin, and a metal filter energy measurement mode. Measurements made using these three modes will be presented along with comparison to thermal and beam source X-ray models.