A Transistorized Particle Identifier

The particle identifier described is based on an approximation of Bethe's calculation, which is commonly used in nuclear reaction experiments. The outputs of two logarithmic amplifiers are added together and inverted, in an antilogarithmic circuit, to form the inherent product. The logarithmic amplifiers are operational amplifiers with two parallel, inverted, feedback silicon diodes. The logarithmic inverter, being symmetrical to the amplifiers, provides temperature compensation of the logarithmic elements. The circuit is designed to handle bipolar pulses of 1 μs width, like those obtained from common double line differentiated amplifiers. Curves showing actual identifier spectra are provided.