Quench, volume and activity determinations in a liquid scintillation

Abstract

A method for use with liquid scintillation flow systems including flowing a mixture comprising a sample and a liquid scintillation medium through a flow detector, the liquid scintillation medium including a radionuclide marker having an energy distribution different from the sample. A pulse height distribution spectrum is determined and a unique point on the portion of the pulse height distribution spectrum representing the energy spectrum of the medium is found, a pulse height value related to such unique point providing a value related to the degree of quench present in the mixture. By comparing such pulse height value to a pulse height value obtained in a like manner for a calibration standard, a degree of quench present in the mixture is indicated. Furthermore, the counts detected for the liquid scintillation medium during a measurement period may be related to the specific activity of the liquid scintillation medium to determine the volume of liquid scintillation medium flowing during the measurement period. The volume of sample flowing during such period may also be determined by relating the liquid scintillation medium volume to a ratio of sample to liquid scintillation medium flowing through the flow detector. Sample count rate is corrected for quench and sample specific activity is determined.