Parallel-Plate Counters and the Measurement of Very Short Time Intervals

The counter characteristics of a discharge tube using plane-parallel electrodes have been investigated, particularly with regard to the short time lags inherent in the streamer type of spark which occur with such a geometry at near-atmospheric pressure. Construction details for parallel-plate counters with good counter characteristics are given. Spurious counts were minimized by an argonxylene filling mixture and the use of a univibrator quench circuit. The uncertainty in the reaction time of the counters is ±5x10-9 sec. Also described is a timing circuit which, in conjunction with the new counters, makes possible the measurement of time intervals between ionizing events to a precision of ±5x10-9 sec.