On gamma-ray spectrometry pulses real time digital shaping and processing

In gamma-ray medical imaging and nuclear spectroscopy instruments, deployment of high speed reconfigurable field programmable gate arrays circuits make it possible to implement signal processing algorithms for pulse shaping, pile up detection and correction, and determination of pulse amplitude and its time of detection in real time. Based on this idea, we have developed a digital pulse processing board for use in a gamma ray spectroscopy and later in positron emission tomography. The proposed digital pulse-processing core relies on digital trapezoidal or triangular pulse shaping, an automatic baseline correction and pileup rejection methods, all of which are implemented in FPGA to permit on-line event processing. Experimental results show that because of its pulse shaping method, system throughput and energy resolution significantly outperforms analog pulse processing systems.