Differential Current Pulse Preamplifier for Fission Counters

A current-pulse preamplifier with a differential input was developed for use with fission counters where there might be severe electrical interference. Tests with a vacuum tester coil show only a slight alteration of the normal noise background curve by the differential preamplifier but a great alteration by a single-ended preamplifier. Additionally, measurements show that if a differential current signal is obtained from the fission counter, the differential preamplifier can improve the signal-to-noise ratio (for electronic noise) nearly a factor of ¿2 over that of a single-ended unit. Tests of five prototypes built by a commercial manufacturer to RDT standards show good uniformity of performance, including gain stability, rise time, and linearity, well within the specified requirements.