Multi-color gated x-ray pinhole imaging of Z-pinch implosions on the Saturn and Z pulsed power generators

Magnetically driven implosions of wire array and gas puff loads on the 20 MA Z and 8 MA Saturn pulsed power drivers provide extremely intense x-ray sources. Each facility fields multi-frame, multi-color, x-ray pinhole cameras in order to assess source uniformity and study implosion dynamics. The instruments feature cameras filtered for >1 keV photons, as well as pinhole cameras in which <1 keV images are reflected from planar multilayer mirror (MLM) monochromators 1 . Microchannel plate cameras provide <1 ns time resolution, and spatial resolutions of 100–500 µm are typical when imaging >10-mm-scale z pinches. A Cr/C MLM on the Z machine is used routinely for 277 eV monochromatic imaging with <10 eV bandwidth, showing a broad shell of imploding wire array plasma which generates 1–10 keV K-shell x-rays when it stagnates on the axis of symmetry. After peak x-ray power, an m=1 instability is seen to grow rapidly, followed by the pinch column breaking and disrupting late in time. This 277 eV imager may also be used for hohlraum hole closure measurements on Z. A W/Si mirror reflecting 528 eV images corresponding to an L-shell emission line of Ar has been demonstrated in Saturn gas puff experiments. A zippered implosion is observed, with K line emission generated as the plasma arrives on axis, and L-shell radiation following as the plasma cools. Collisional radiative modeling may be employed to understand line and continuum contribution to the imaged signal, and to generate synthetic images.