10 keV to 100 keV non-thermal radiation from high-Z exploding wires

Summary form only given. There is an interest in 10 keV to 100 keV radiation sources for some types of radiation-interaction studies. The approach presented here uses non-thermal radiation from single-wire radiators (SWRs). An SWR is a high-Z exploding wire that produces many small, bright radiation sources along its length during a fast (<; 100 ns) high-current (~ MA) discharge. In previous experiments, tungsten wires produced spectra with 60 J above 10 keV with an effective endpoint of about 100 keV. An array of many, non-interacting SWRs is proposed to generate a higher yield in this energy range. SWRs were investigated in the 1970s on the Gamble II generator (~ 1 TW, 60 ns) at the Naval Research Laboratory. The wire is connected between the negative-high-voltage center conductor (cathode) and the grounded outer conductor (anode). The current pulse causes the wire to explode then the self-magnetic field compresses the resulting plasma. The typical peak current was 0.7 MA with 1.4 MV developed across the wire. SWRs produce copious thermal radiation in the XUV to several-keV region, and nonthermal x-rays in the 10 to 100 keV region, primarily as bremsstrahlung, and line radiation from inner-shell vacancies in high-atomic-number plasmas. Modern, higher-current drivers produce far more thermal radiation with energies typically less than 10 keV, from imploding gas-puff and wire-array z-pinches. Now, there is renewed interest in the SWR technique for producing higher-energy radiation in the roughly 10 keV to 100 keV regime. For recent experiments on Gamble II, tungsten wires of 50 Pm diameter and 35 mm length are used, optimized conditions based on experiments in the 1970s. The radiation is detected using various diagnostics, including: thermoluminescent-dosimeters, a scintillator-photodiode, a PIN-diode array, a pinhole camera, multiple-filter x-ray transmission measurements and curved-crystal spectroscopy. Results from initial experiments using these diagnostics will be reported.