Mixed gas Z pinch experiments using a shell-on-shell nozzle on Double-EAGLE

A series of Z pinch experiments using argon and krypton was conducted on the Double-EAGLE pulse power driver at 3.5 to 4.0 MA peak current and 170-190 ns implosion time. A shell-on-shell nozzle provided the opportunity to separate the two gases and to control which was driven more strongly (by virtue of being in the inner plenum). With argon in the inner plenum, 12 to 16±3 kJ krypton L-shell and 8 to 10±3 kJ of argon K-shell radiation was produced. With krypton in the inner plenum, 23.6 ±2.5 kJ of krypton L-shell and 2.5±2.3 kJ of argon K-shell radiation were produced. Since the optimum implosion times for the two gases were different, changing the mass of the z pinch varied the ratio of the yields. Using a streak spectrograph and PCDs with a Ross filter pair, the time history of the krypton and the argon radiation could be distinguished and seen to be simultaneous. Spectroscopic measurements of a chlorine dopant in the inner shell gas demonstrated that the implosions with krypton achieved lower density and electron temperature than with argon whether the krypton was in the inner or outer plenum.