Optimal Design of Waveform Digitisers for Both Energy Resolution and Pulse Shape Discrimination

TL;DR

This paper analyzes how waveform digitiser parameters affect energy resolution and pulse shape discrimination in scintillator detectors, providing guidelines for optimal digital system design based on noise analysis.

Contribution

It offers a quantitative analysis of digitiser properties influencing energy resolution and PSD, establishing design rules for LaBr3(Ce) scintillators.

Findings

Sampling rate and vertical resolution significantly impact energy resolution and PSD.

Optimal digitiser design balances noise considerations for both applications.

Guidelines improve digital acquisition system performance for scintillator detectors.

Abstract

Fast digitisers and digital pulse processing have been widely used for spectral application and pulse shape discrimination (PSD) owing to their advantages in terms of compactness, higher trigger rates, offline analysis, etc. Meanwhile, the noise of readout electronics is usually trivial for organic, plastic, or liquid scintillator with PSD ability because of their poor intrinsic energy resolution. However, LaBr3(Ce) has been widely used for its excellent energy resolution and has been proven to have PSD ability for alpha/gamma particles. Therefore, designing a digital acquisition system for such scintillators as LaBr3(Ce) with both optimal energy resolution and promising PSD ability is worthwhile. Several experimental research studies about the choice of digitiser properties for liquid scintillators have already been conducted in terms of the sampling rate and vertical resolution. Quantitative analysis on the influence of waveform digitisers, that is, fast amplifier (optional), sampling rates, and vertical resolution, on both applications is still lacking. The present paper provides quantitative analysis of these factors and, hence, general rules about the optimal design of digitisers for both energy resolution and PSD application according to the noise analysis of time-variant gated charge integration.