Monochromatic X-Ray Self-Emission Imaging of Imploding Wire Array Z-Pinches on the Z Accelerator

Summary form only given. A monochromatic X-ray self-emission imaging diagnostic has been developed for the Z accelerator, which drives 20 MA in 100 ns to implode wire array Z-pinches, generating 200 TW of soft X-ray radiation. This instrument reflects eight pinhole images from a flat Cr/C multilayer mirror (MLM) onto a 1 ns time-resolved microchannel plate detector. The MLM reflects 277 eV photons with 5 eV FWHM bandwidth and 20% peak reflectivity, and an aluminized parylene filter shields the detector from visible light. High-energy bremsstrahlung X-rays do not follow the reflected beam path, and so the background on the shielded detector is reduced compared to a standard pinhole camera. Additionally, the MLM-reflected images offer spectral resolution that filtration alone cannot. Adjacent to this instrument in the same beamline is a second eight-frame standard pinhole camera filtered to image keV photons simultaneously. Initial data on Z from W, Cu, and stainless steel wire arrays will be presented. Observed phenomena including implosion instabilities, zippering and hollow features in the plasma column during the onset of stagnation, accretion of trailing colder mass, and cathode re-emission will be discussed. Future work will extend monochromatic imaging to higher photon energies, including several-keV K-shell sources