Spectroscopic Measurements from the X-ray bursts of 4-wire Manganin X-pinches

Dr. Katherine Chandler
Laboratory of Plasma Studies
Cornell University, Ithaca, NY

X-ray spectroscopy provides a non-invasive diagnostic to study the properties of dense plasma that emit X-rays. Experiments involving both time-integrated and time-resolved Cu and Mn spectra in the 1-8 keV photon energy range from 25 µm Manganin (84% Cu and 16% Mn) wire X-pinches were conducted using a 450 kA peak current, 100 ns (full width at half maximum) pulser. Our studies show that He-like (27 times ionized) Cu line radiation was emitted, revealing electron temperatures of up to 1.5 – 1.7 keV for the hottest regions of the plasma. Helium-like Mn radiation emitted from the same shot gives the same temperature, indicating that both of these constituents of the alloy were radiated from the same source. Time-integrated and time-resolved experiments have shown the same intensities and electron temperatures for Ne-like (19 times ionized) Cu radiation from two x-ray bursts emitted by the same X-pinch, which has not been true for X-pinches using other wire materials. The evolution of the Ne-like Cu line radiation from Manganin X-pinches, investigated using a streak camera with picosecond time resolution, shows evidence of Ne-like lines being emitted before the intense continuum radiation characteristic of an X-pinch x-ray burst. This is also at variance with previous experiments involving Mo, in which the Ne-like lines are emitted later than or at the same time as the continuum radiation. Also, the streak camera results show that the He-like Cu lines have a much shorter duration (<100 ps) than the Ne-like lines (~1 ns) from the Manganin X-pinches and there is no detectable intense continuum in this energy range. A simple Gabriel model has been implemented to extract the electron temperature from the experimental spectra. The results of the experiments as well as the application of the Gabriel model will be discussed.