Low-Noise, Wide-Band, Current-Pulse Preamplifiers for Neutron Counters

An improved, low-noise, wide-band current preamplifier was developed for use with a fission counter having a 100-nsec electron collection time. The signal-to-noise ratio of the preamplifier and its insensitivity to component parameter variations and temperature changes exceed that of any commercially available unit. A differential version was developed to exploit the balanced configuration of the counter. A 20% improvement in signal-to-noise ratio was obtained with good common-mode rejection from 50 kHz to 30 MHz.