Characterization of laser-produced bremsstrahlung for x-ray radiography of pulsed-power driven mm diameter metal rods

A Mega Ampere current pulsed power system with a ~ 100 ns rise time can quasi-isentropically compress a millimeter diameter solid metal rod to strongly coupled plasma. To develop an x-ray source for probing such a plasma, we carried out a short-pulse laser experiment at University of Nevada Reno's Nevada Terawatt Facility using a 50 TW Leopard laser to characterize high energy bremsstrahlung both in a laser and Zebra pulsed power chamber. Bremsstrahlung and fast electrons generated in the laser interaction with silver foils (10, 20 and 100 μm thickness) and a 25 μm diameter silver wire were recorded with a Image plate-based filter stack bremsstrahlung spectrometer and a magnetic electron spectrometer. The x-ray sources were used to obtain x-ray images of undriven Al rods with 0.5, 1.0 and 1.6 mm diameters. Among the targets we studied, the highest x-ray yields were observed with the 10 μm thick foil while the better spatial resolution of the image was obtained with the wire target. The experiment and analysis of the source using hybrid Particle-in-cell simulations will be presented.