Development of the digital multichannel analyzer for liquid scintillation detection

Abstract

The new digital multichannel analyzer (DMCA) based on field programmable gate array (FPGA) technology is successfully developed, and it is used for liquid scintillation detection. The performance of this system has been evaluated. The analog signal output emanating from the photomultiplier tube (PMT) is transformed into digital signals through the utilization of an amplifier and a high-speed analog-to-digital converter (ADC). Information about the energy, timing, and pulse shape characteristics of the radiation event is contained in the digital signal. Subsequently, this digital signal is directed towards the FPGA for digital signal processing. In order to reduce the thermal and electronic noise, the dual-channels configuration and the signal coincidence function are added to DMCA for optimizing the validity of signal. The signal coincidence unit is designed within the FPGA, optimizing the synchronization of signals. The measurement data is transmitted to a computer via USB interface. The energy spectra of gamma sources, namely 22Na, 60Co, and 137Cs, as well as the alpha source 232Th, were measured utilizing the newly developed system. Notably, thermal and electronic noise interference is reduced in the coincidence measurement mode, and the coincidence energy spectra are improved compared to the singles measurement. In contrast to commercially available systems, the advantages of our design in terms of miniaturization, cost-effectiveness, and expandability are demonstrated.