In this paper a fast digital real-time spectrometer was developed for timing and analysis of nuclear pulse signals.The hardware system design and algorithm implementation with field-programming gate array(FPGA) and digital signal processor(DSP) were introduced.The performance of the digital constant fraction discrimination(dCFD) platform was experimentally tested with Agilent 80 MHz function/arbitrary waveform generator and LaCl 3:Ce 3+ scintillator detector for 22 Na positron annihilation gamma spectroscopy.The amplitude and time information of photon was online obtained.The energy resolution could be 5.525% and the timing resolution 293.75 ps,the system error estimation of dCFD approach was also studied.The results showed that this spectrometer achieved a timing resolution close to that of traditional CFD timing resolution with a more simplified system structure.
We designed a universal digital energy spectroscopy based on online digital signal processing. A prototype system was built and tested. Signals from radiation detectors were processed via a digital filter whose coefficients could be modified without changing the hardware. The paper introduces the hardware design of the digital energy spectroscopy system as well as the full set of software consisting of the selection of the coefficients of the finite impulse response (FIR) filter and the coding in the field-programmable gate array (FPGA). The system was tested with the high purity germanium (HPGe) detector. The results showed that this prototype can achieve an energy resolution close to that of a traditional multi-channel analyzer (MCA) with a much higher counting rate.
