Techniques for improved surface discharge switch performance

Summary form only given, as follows. Several techniques have been developed to improve the performance of surface discharge switches (i.e., SDS). These improvements will be reported in this investigation and are planned for the development of a prototype switch for the Atlas experimental facility at Los Alamos National Laboratory. One performance improvement technique consists of implanting graphite inserts in the insulator substrate to form capacitively-coupled field emission points with the underlying trigger electrode. These capacitively-coupled field emission points have reduced the trigger risetime normally required for efficient multi-channeling from 1000 V/ns to 60 V/ns. The resulting discharge has many channels and appears nearly sheet-like in nature. The improved multi-channeling allows the electrodes, which normally rest directly on the insulator surface, to be raised off the insulator surface thereby extending the lifetime of the insulator. Lifetime tests for the improved SDS has been done for 5000 commutations at 15 kV switch holdoff voltages, 750 kA peak currents, and 70 /spl mu/s wide pulses. The switch was in good condition at the end of this test and had recorded only 10 prefires during this test. To meet the switch performance requirements for the Atlas facility, further improvements in switch prefire and jitter performance can be accomplished.