Pulse shape analysis of avalanche counters

It is well known that the response of gas-filled radiation detectors, operating under gas amplification, is adversely affected by the space-charge effect of positive ions created in electron avalanches. In this paper, we have analysed the reflection of the space-charge effect on the shape of output pulses from a parallel-plate avalanche counter. It is shown that, under the space-charge effect, the shape of output current pulses has a striking dependence on the amount of primary ionization, providing a means for the discrimination of particles of different energy deposition in the detector. A pulse-shape analysis method is described to exploit this property, and the method is verified in a simple experiment by using α-particles of different specific energy-loss. (author)