A 44 Joule 2 kHz pulse repetition frequency excimer laser PFL charging system

Research to produce an excimer laser with a mean output power of 1 kW is critically dependent on the concurrent development of pulse power systems which are capable of sustaining laser gas discharges at pulse powers in excess of 100 MW, over pulse duration of a few hundred nanoseconds and at pulse repetition frequencies (PRF) above 1 kHz. Such pulses are generated by magnetically-switched pulse forming lines (PFL) which must be charged to peak voltages above 10 kV in around 1 μs. This necessitates switching on the PFL charging circuit at kA power levels and at mean powers approaching 100 kW. Hydrogen thyratrons incorporating hollow anode designs have proven to be a reliable switching element in circuits of this type, with reverse conduction characteristics which ensure prolonged lifetime operation at multi-kilohertz pulse repetition frequencies even under extreme conditions of current reversal. The development of a thyratron switched, multi-stage resonant charging system capable of delivering 44 Joules in 1 μs at a PRF of 2 kHz is discussed. In particular the author discusses the development of a PFL charging system