Spark-Gap-Trigger Amplifier

Short over-all time delay, low time jitter, and excellent long-term reliability are among the desirable features designed into a pulse generator that produces a 2-MW output pulse 30 nsec after the application of a 1-V signal at its 50-ohm input connector. The 10-kV output pulse can be used to trigger simultaneously several spark gaps of the type used in spark-chamber pulse modulators. The 10 power gain of the spark-gaptrigger amplifier is achieved by four stages of amplification packaged in a 5-1/4 in. rack-mount chassis that operates directly from a 117-V line. The individual stages, each selected to give minimum time delay for a given power gain at their respective power levels are: avalanche transistors, planar triode, grounded-grid planar triode, and a triggered-spark gap. The techniques used for the last stage, a spark gap triggered by a corona light, are of particular interest since the same techniques are applicable to obtaining short time delays and long-term reliability from the larger spark gaps that the amplifier was designed to trigger. During 10 months of operation, there have been no failures and no adjustments necessary in any of the seven spark-gap trigger amplifiers used in various spark-chamber experiments at the Lawrence Radiation Laboratory of the University of California (UCLRL) in Berkeley.