X-ray Diagnostics for the Flow-Shear-Stabilized Z-Pinch

Two multi-foil X-ray probes for electron temperature measurements have been fielded on FuZE. The probes consist of 7 thick Si PIN photodiodes, each with separate foils, optimized for measuring temperatures of order 1 keV. The probes also contain paired filters that allow detection of the presence of higher-energy X-rays (10-20 keV). Relative calibration of the detector sensitivities & estimation of the error due to the imperfect overlap of each diodes’ field of view are provided by testing with uniform filters applied to all channels. A Bayesian analysis process is implemented using non-informative priors.



An X-ray pinhole camera has also been fielded to measure the spatial distribution of X-ray production. Initially a phosphor scintillator screen coupled with a visible-light camera was used to detect X-ray photons with single frames per shot. We observe localized emission from edges of in-vessel metal components, in addition to more diffuse emission presumed to be from the pinch plasma. A direct-detection X-ray image sensor, capable of 5 MHz frame rate for hundreds of frames, will be evaluated. The high efficiency of the sensor is expected to provide adequate signal-to-noise ratio at high temporal and spatial resolution.