COINCIDENCE COUNTING

in physics, the detection of two nuclear or cosmic ray events that occur almost simultaneously (e.g., within a time of 10-5 second). Coincidence counting involves two or more particle counters exposed to the same source of cosmic rays or nuclear radiation and connected to an electronic coincidence circuit. One principal use of the coincidence technique is to detect particles emitted simultaneously from the same nucleuse.g., a beta particle and a gamma ray photon. In anticoincidence counting, two counters are connected so that a pulse from a cosmic ray or nuclear particle is recorded by one of them only if there is no simultaneous pulse (for example, by a spurious event) in the other.