Fast Coincidence System with Amplitude Discrimination and Accidentals Monitoring

A coincidence system with a short resolving time, variable up to 120 millimicroseconds, has been developed for use in (α, pγ) and (d, pγ) correlation investigations. The system is a ``slow‐fast'' one in that amplitude selection in both channels is made before the pulses reach the fast coincidence circuit, while accurate timing is achieved by parallel delaying and sharpening networks in each channel. The advantage of the slow‐fast method is that it permits the inclusion in a simple way of an accurate monitor for accidental coincidences, thus allowing continuous accidentals monitoring while an experiment is in progress. A description of the whole system and details of new circuits and special components are given.