<title>Pseudospark switches for excimer-lasers and pulsed CO<formula><inf><roman>2</roman></inf></formula> lasers</title>

Abstract

Sealed-off, metal-ceramic pseudospark switches are currenfly developed as a replacement of conventional thyratrons in pulsed gas discharge lasers. The gross performance of pseudospark switches exceeds that of thyratrons in many facts, like peak current, current reversal capability and rate of current rise. One of the major problems which has to be solved is the increase of lifetime of the pseudospark switch which should be comparable to that of conventional thyratrons. In this contribution the performance of different type of pseudospark switches at different load conditions typical for pulsed gas discharge lasers will be discussed. Experiments were performed at a low inductive 1 Q water pulse line at holdoff voltages of up to 32 kV with a dJ/dt of 6* 1 A/s (10% -90 %) and a maximum current of 30 kA. Switch parameters like delay, jitter, misfiring rate and current rise were continuously recorded at repetition rates of up to 100 Hz. By adjusting the reservoir current and herewith the gas pressure of the switch to the applied voltage a jitter of less than 5ns can be achieved. The delay is dependent on the rise time of the trigger pulse and is 650 ns at a voltage rise of 5 kV/600 ns and has a minimum of 200 ns with a trigger pulse of 5 kV/18 ns voltage rise. By biasing an auxiliary electrode, which is mounted inside of the hollow cathode, the jitter can be decreased to values below 1 ns. SPIE Vol. 2206/219Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/24/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx