Development of a Compact Digital Multichannel Analyzer based on FPGA

Abstract

In this work, we designed and built a digital multichannel analyzer (DMCA) using field-programmable gate array (FPGA), which is used to build a spectroscopic measurement system for a tomography device. DMCA's hardware was built with an ADC with 14-bit resolution and a sampling rate of 105 million samples per second (MSPs) combined with an FPGA board. The models of three functional blocks in DMCA, including pulse shaping filter, peak detection, and spectrum histogram processing, were simulated and optimized in the Matlab environment before they were integrated on the FPGA chip. The performance of DMCA was evaluated based on the high purity germanium (HPGe) detector with standard sources 60Co and 137Cs. The spectrum measured on the DMCA system showed that the drift of the spectral peak over time (100 hours) was of less than 1% and a resolution of 2.6 keV was at 1332 keV 60Co. The DMCA developed in this work demonstrated various advantages: stability, compactness, versatility, and cost effectiveness.