An improved coincidence counting technique for standardization of radionuclides

A data acquisition system based on a coincidence controller with buffer memory has been developed for standardization of radionuclides. The energy and output time of the shaped linear pulses generated from an ADC are digitized and latched by a 10 MHz clock oscillator, then these data are stored in the random access memory (RAM) of the coincidence controller. The coincidence resolving time and gamma windows can be selected by an off-line computer analysis program and the efficiency function is obtained by a computer discrimination method. This method is well suited for absolute activity measurement of radionuclides with relatively long-lived intermediate states as well as prompt decay.