A Comparator-based Pulse Height Analyzer for Gamma Spectroscopy

This paper presents the design and implementation of a low-cost pulse height analyzer for gamma spectroscopy. The system measures the amplitude distribution of short electrical pulses at its input, typically generated by scintillation detectors. It explores the feasibility of using a bank of integrated comparators within a microcontroller to replace traditional analog-to-digital conversion methods. Key challenges, such as synchronization, precision, and peripheral configuration, are addressed in the paper. The prototype is based on a microcontroller with integrated DACs, comparators, and timers, enabling fully embedded signal processing with minimal external components. For 1 mu s-wide input pulses and a 20mV comparator window, the system achieves sorting accuracy above 96 %, with amplitude resolution of 10mV per step. The measurement results can be streamed in real time via USB or network interface. Compared to conventional solutions, the proposed system offers a compact, energy-efficient, and accessible alternative for pulse amplitude analysis in nuclear instrumentation and related fields.