Event vertex and time reconstruction in large volume liquid scintillator detector

TL;DR

This paper evaluates four algorithms for reconstructing event vertices and times in large liquid scintillator detectors, highlighting the impact of photomultiplier tube properties and the effectiveness of charge versus time data.

Contribution

It provides a comprehensive analysis of vertex and time reconstruction algorithms and investigates the influence of photomultiplier tube characteristics on performance.

Findings

Transit time spread significantly degrades vertex reconstruction.

Dark noise has limited impact on reconstruction accuracy.

Charge information outperforms time data near detector boundaries.

Abstract

Large-volume liquid scintillator detectors with ultra-low background levels have been widely used to study neutrino physics and search for dark matter. Event vertex and event time are not only useful for event selection but also essential for the reconstruction of event energy. In this study, four event vertex and event time reconstruction algorithms using charge and time information collected by photomultiplier tubes were analyzed comprehensively. The effects of photomultiplier tube properties were also investigated. The results indicate that the transit time spread is the main effect degrading the vertex reconstruction, while the effect of dark noise is limited. In addition, when the event is close to the detector boundary, the charge information provides better performance for vertex reconstruction than the time information.