1 MV repetition-rated modulator

The design of a 1 MV, repetition-rated modulator capable of switching 20 kJ into an 80 Ω load is presented. The design utilizes two recently developed 100 kV hollow-anode thyratrons to discharge four parallel lumped-constant Blumleins composed of two 1.0-2.0 Ω, 6-stage, type E pulse-forming networks (PFNs). The Blumleins are to be command-resonantly charged from a capacitive energy storage bank to 100 kV and then discharged through a 10:1 step-up iron core transformer to 1 MV. The primary switch thyratrons in the modulator must be able to hold off 100 kV and conduct currents up to 200 kA with as di/dt approaching 10¹² A/s total. Preliminary work has shown that the main switch tube, with PFNs, and the command charge circuits perform satisfactory at half their rated values (50 kV)