Systematic Effects in Pulse Shape Analysis of HPGe Detector Signals for Neutrinoless Double-Beta Decay

TL;DR

This paper investigates systematic uncertainties in pulse shape analysis for HPGe detectors used in neutrinoless double-beta decay experiments, quantifying their impact on background rejection efficiency.

Contribution

It provides a detailed assessment of systematic uncertainties affecting pulse shape discrimination in germanium detectors for rare decay searches.

Findings

Total uncertainties are 6.6% for double-escape peaks.

Uncertainties are 1.5% for continuum events.

Uncertainties are 3.8% for gamma-ray events.

Abstract

Pulse shape analysis is an important background reduction and signal identification technique for next generation of neutrinoless double-beta decay experiments examining 76Ge. We present a study of the systematic uncertainties in one such parametric pulse-shape analysis technique for separating multi-site backgrounds from single-site signal events. We examined systematic uncertainties for events in full-energy gamma peaks (predominantly multi-site), double escape peaks (predominantly single-site) and the Compton continuum near double-beta decay endpoint (which will be the dominant background for most neutrinoless double-beta decay searches). In short, we find total (statistical plus systematic) fractional uncertainties in the pulse shape cut survival probabilities of: 6.6%, 1.5% and 3.8% for double-escape, continuum and gamma-ray events respectively.