Application of digital sampling techniques for coincidence counting

The 4 π β ( LS ) ‐ γ coincidence counting system of KRISS (Korea Research Institute of Standards and Science) has been operated in the analog signal-processing mode. We develop and implement a digital sampling method using a commercially available analog to digital converter. In the implementation, we digitize the amplified pulse trains generated from three detector channels and determine the locations and amplitudes of peaks using a peak detection algorithm. We develop offline analysis routines to process the recorded locations and amplitudes for activity determinations by means of the efficiency-extrapolation method. In the activity determinations we can make corrections for the effects of out-of-channel events and correlation between data points. We validate the digital sampling method by measuring 60Co activity and comparing the measurement results with those obtained in the analog mode. The digital method is capable of facilitating the activity standardization of radionuclides with very short half-lives.