A Calculation Software for 4πβ–γ Coincidence Counting

In order to absolutely measure the radioactivity of β-γ decay radionuclides, we have developed a calculation software for 4πβ-γ coincidence counting. The combination of software and hardware systems constitutes an absolute radioactivity measurement system. The hardware uses a NaI (Tl) γ-ray detector and 4πβ proportional counter as front detectors. The software uses a 4πβ-γ coincidence efficiency extrapolation method to obtain source radioactivity by processing β and γ pulses digitalized by a data acquisition device. Processing modules in the software include a peak-finding module, data conversion module, dead-time processing module, multichannel coincidence module, and efficiency extrapolation module. To evaluate the measurement system, the software is used to measure the known radioactivity of ⁶⁰Co sample and then the results were compared. Test results indicated that coupled with the above hardware system, the software accurately measured the absolute radioactivity of ⁶⁰Co, proving that this software can successfully absolutely measure the radioactivity of β-γ decay radionuclides.

I. Introduction

In the field of radionuclide metrology, – coincidence counting is the prevailing method for the absolute determination of the radioactivity of – decay radionuclides. However, the measurement results of this method are easily affected by scattering and absorption of rays. To reduce these effects, the – coincidence efficiency extrapolation method was developed. It places a radioactive source into a -ray detector with a detection angle [1].