A digital coincidence measurement system using FPGA techniques

A digital coincidence system for nuclear radiation measurement has been developed. The analog output signal from detector is transferred into digital signals by pulse height to pulse width converter. The digital signal contains the energy and timing information of the radiation events. The information is further processed using FPGAs for coincidence examination. The result is then sent to a personal computer for spectrum display. The digital system has been used with NaI scintillators for efficiency calibration and for measuring 0.511 MeV annihilation radiations. Results indicated that the digital system is flexible and easy for parameter adjustment compared with conventional analog systems.