Scintillation counting system for in-situ measurement of radioactive samples in a multiple-well plate

摘要

A system for in-situ measurement of the radioactivity of multiple samples while the samples are in a multiple-well sample tray, with a scintillator in each sample-containing well for producing light pulses in response to radiation from the respective samples. Multiple photomultiplier tubes are positioned adjacent to the sample wells containing the scintillator for simultaneously measuring the radioactivity of multiple samples with only a single photomultiplier tube sensing the scintillations from each well and converting the sensed scintillations into corresponding electrical pulses. The electrical pulses from each photomultiplier tube are processed to discriminate between pulses attributable to sample events within the wells and pulses attributable to non-sample events such as photomultipler tube noise. The discrimination is effected by determining whether a selected number of electrical pulses occurs within a prescribed time interval, the occurrence of the selected number of pulses within the prescribed time interval signifying a sample event. Only the electrical pulses attributable to sample events are supplied to a pulse analyzer.