PFNs switched with stacked SCRs at 20 kV, 500 J, and 100 Hz REP-rate

Abstract

Innovations in high power stacked SCRs, employed for switching high voltage and high di/dt current pulses, show applications in high power laser systems. The use of stacked SCRs opens the field for the replacement of thyratrons or spark gaps by high current thyristors (HCTs). At the DLR, the development of a pulsed, high power CO/sub 2/-laser (electron beam sustained) with an average output power of more than 15 kW has been accomplished. The operation of the electron beam sustained CO/sub 2/-laser system has been done by the use of a cold cathode electron beam accelerator (transformer 1:10, 200 kV). This paper presents the experimental results of a stack of 8 SCRs (HCT 2003-45: forward blocking voltage 4.5 kV, ABB Research Laboratory) used as the electrical switch for the electron beam accelerator of the high power CO/sub 2/-laser. The requirements for the switch of the electron beam accelerator are: 20 kV loading voltage, 500 J stored PFN pulse energy, time dependent electron beam accelerator load from k/spl Omega/ to a few 100 /spl Omega/, 2-10 /spl mu/s pulse duration, bursts of a couple of hundred pulses, and 100 Hz repetition rate. Two seven-section PFNs were connected in parallel to generate a 2-10 us long pulse into two different test loads R/sub load/: (1) ohmic load and (2) and (3) dynamic electron beam accelerator load.