Demonstration of a “gas anode” current return for a z-pinch

Summary form only given. We have developed and successfully operated a "gas anode" for use with z-pinch plasma radiation x-ray sources (PRS). The gas anode replaces the multiple solid anode-current- return rods of a standard PRS with a cylindrical shell of low atomic number gas. Beginning at the start of current flow, either via pre-ionization by UV flashboards or via high voltage breakdown, the anode gas conducts the return current flow of the pinch for the duration of the implosion and beyond. The benefits of the gas anode are two-fold. First, it eliminates the solid anode posts as a source of particulate debris during and after the implosion. Second, the gas shell will attenuate the far UV and slow/stop some of the debris of the pinch, potentially eliminating or reducing the need for complex lithium filter systems. We will present the results of experiments using a gas anode on the 600 kA HAWK generator. The gas anode proved to be a viable replacement for the anode return posts. The performance of the neon z-pinch was not degraded. In addition, it was shown that the anode screen normally used with the PRS was not needed with the gas anode. The mass emitted by the gas anode on the HAWK shots did prove insufficient to attenuate few micron particle debris and UV, but debris reduction for particles larger than 10 microns was demonstrated. Additional testing is needed to more completely establish the quantitative benefit of the gas anode for debris and UV reduction.