Pulse Generators with Nanosecond Leading Edge Duration Based on TPI-Type Pseudospark Switches for FEL Complex

Summary form only given. For the FEL (Free Electron Laser) complex in Duke University five pulse generators (kickers) were developed and built. As fast switches TPI-type thyratrons (pseudospark switches) are used. In contrast with other pseudospark switches TPI-thyratrons are capable of operating in circuitry with a grounded cathode which allows obtaining service life time up to 20 000 hours. The thyratrons can be considered as an alternative to well-known switches, including hot cathode hydrogen thyratrons and up-to-date power solid state switches, whereas being more compact and cost effective compared to the latter. The absence of a hot cathode provides for turn-on time for the thyratrons of about 3-5 ns in modes with thousands-amperes peak currents and sub-nanosecond jitter. Injection generator is built using compact TPI1-1k/20 thyratron, making in a load with impedance of 50 ohm square bi-polar pulses with duration of 100 ns, pulse leading edge of 5-10 ns and "forepart flattop" instability not greater than plusmn5% at the peak overall voltage on deflecting plates from 5 to 10 kV. Extraction generator is built also on TPI1-1k/20 thyratron. It provides in a load with impedance of 50 ohm pulses with duration at level 0.1 not more than 15 ns at the peak overall voltage on plates from 8 to 40 kV. Generator of injection into a big ring is built on power TPI1-10k/20 thyratrons. With plate impedance of 25 ohm it provides for pulse duration at level 0.1 not more than 100 ns at the peak overall voltage on plates from 10 to 50 kV. Results of pulse generators service within over 1.5 years are presented.