Coincidence and Dead-Time Corrections for Particle Counters. Part I: A General Mathematical Formalism

Abstract

Counting loss due to coincidences limit the efficiency of the retriggerable particle counters. When the particle rate increases, the counted rate rapidly reaches a maximum so that it becomes impossible to precisely estimate the actual value. On the contrary, the activity time of the probe increases continuously and is a more efficient parameter for high concentration measurements. Exact relationships between these parameters and the actual particle rate are given here for particles randomly dispersed according to a Poisson distribution. Relations between activity and counted particle rate are also useful for the evaluation of the heterogeneities in the spatial distribution of the particles.