A LOW-NOISE FAST-ACTING AMPLIFIER WITH A CABLE AT ITS INPUT

The preamplifier is intended for operations with fast-acting fission c hambers. It can operate with a long connecting cable at its input. The preamplifier consists of differentiating and integrating assemblies. The duration of output pulses is 0.2 mu s, the maximum amplitude is ab out 5 V. The root-mean-square magnitude of the intrinsic noise (in uni ts of the number of electrons) is 3 x 10(3). When the preamplifier is connected by a 20-m cable to a fission chamber with a capacitance of 2 00-400 pF, the noise increases up to 15 x 10(3). When a 50-m cable is connected to the preamplifier input, the noise level does not exceed t he maximum amplitudes of signals from alpha-particles.