Design and performance of two 100-GW linear transformer drivers

Abstract

Summary form only given. We have developed and tested two prototype linear transformer drivers (LTDs): LTD III [1], which is a single LTD cavity that generates a peak electrical power of 79 GW, and Mykonos II [2,3], which is a two-cavity 142 GW LTD module. LTD III is driven by 20 bricks, each of which includes an 85-nH gas switch and two 60-nF capacitors. LTD III has been successfully tested on 3,500 shots at a charge voltage of +100 kV / −100 kV. The first 1,500 shots were conducted with UV-illuminated gas switches; the last 2,000, with new three-electrode field-distortion switches. Over the course of the last 2,000 shots, the variation of the output power generated by LTD III was 0.9% (one sigma) and the switch pre-fire rate was 1 in 10,000 switch shots after conditioning. Mykonos II is driven by 72 bricks altogether, 36 in each of the module's two cavities. Each brick includes a 115-nH switch and two 40-nH capacitors. Mykonos II is the first LTD module to drive a water-insulated transmission line. Mykonos has been successfully tested on 1,500 shots at a charge voltage of +90 kV / −90 k V. Over the course of these shots, the variation in the output power was 2.3% (one sigma) and the switch pre-fire rate was 1 in 11,000 switch shots after conditioning. Measured output-pulse parameters of LTD III and Mykonos II are consistent with circuit-model predictions. The results obtained suggest that LTDs are a viable prime-power source for next-generation pulsed-power accelerators.