Method for determining random coincidence count rate in a scintillation counter utilizing the coincidence technique

A method is described for the reliable determination of a random coincidence count attributable to chance coincidences of single-photon events which are each detected in only a single detector of a scintillation counter utilizing two detectors in a coincidence counting technique. The method includes the steps of measuring a coincidence count rate as indicated by essentially coincident output pulses from the detectors, measuring a single photon count rate as indicated by output pulses from both of the detectors, whether coincident or not, and determining a random coincidence count rate from the difference between the single photon count rate and the measured coincidence count rate. From the random coincidence count rate thus determined, a percentage error value can be determined, for application, if desired, to subsequently or concurrently measured sample radiation counts