Researches of the Digital Timing Spectrometer based on DSP builder and FPGA

A digital real time spectrometer based on the technology of digital pulse processing has been developed. Based on digital signal processor builder (DSP builder) and Field Programmable Gate Array (FPGA), we realize the digital constant fraction discrimination (dCFD) algorithm part of spectrometer only in FPGA, which will simplify the circuit. A digital ²²Na positron annihilation spectrometer was established to test the system performance. The amplitude and time information of γ photon was obtained online. Both the resolution of energy and time are higher than the conventional CFD spectrometer by a value of 3.90% and 157.6ps respectively.