K-shell radiation characteristics of neon gas puff z-pinches imploded on Qiangguang-I facility

The K-shell radiation characteristics of neon z-pinch plasma with different annular, gas puff nozzles were investigated for implosion times from 70 to 170ns. The experiments were conducted at the 1.6-MA level with a ~60ns risetime on Qiangguang-I facility, whose primary stored electrical energy was about 230 kJ. Assuming a nominal (~1 0:1) compression ratio, a maximum kinetic energy of 5kJ/cm could be reached according to the 0-D slug models, which would produce very high implosion velocities. For a representative load mass of 10μg/cm, this corresponded to η~20 neon imploding plasma, so that efficient K-shell emission could be expected. Several load configurations were tested, such as single shell gas puff nozzles with 20- and 25-mm outer diameter, double shell nozzles with 30-mm outer and 10-mm or 15-mm inner diameters. Filtered x-ray diodes, a time-resolved and integrated pinhole camera, and a four-frame gated spectrometer with TAP curved crystal were used to diagnose the liners. The maximum K-shell yield obtained in the experiments was up to ~7kJ with the radiation power of ~280GW and pulse width of 25ns through the use of double shell nozzle. Emission characteristics of all nozzles, including yields, peak powers, pulse widths, and sizes of emitting area, as a function of plenum pressures, would be analyzed and compared with theoretical predictions of the two-level model (D. Mosher, N. Qi et al. 1998). Temperatures and densities as well as mass fractions of K-shell emitting region were inferred from K-shelliine ratios, powers and images, which would provide further insight into how these quantities depended on load conditions.