Development of a portable TDCR system at NIM, China

In order to meet the demand of on-site measurement for radionuclides, a portable liquid scintillation TDCR system was developed at National Institute of Metrology (NIM), China. The system consists small size TDCR counter for the measurement of liquid scintillation sources, and digital electronics for pulse signal processing. The optical chamber adopts Teflon material with high diffuse reflection efficiency. Two independent signal processing solutions were used here for TDCR counting. One employed the on-line TDCR solution based on FPGA counting module named TDCR-DMCA, and the other adopted the off-line TDCR solution based on a stand-alone desktop digitizer of CAEN. Two solutions are applied to perform coincidence, dead-time and counting operations follow by MAC3 logic. The performance of the TDCR counting system was tested in benchmark comparison with the traditional custom-built TDCR counting system at NIM through activity measurements of ³H, ¹⁴C. Good agreement between these two systems was observed.