Scintillation decay time and pulse shape discrimination in oxygenated and deoxygenated solutions of linear alkylbenzene for the SNO+ experiment

TL;DR

This study measures scintillation decay times in linear alkylbenzene with PPO, demonstrating that deoxygenation enhances pulse shape discrimination between alpha and electron excitations, which is crucial for the SNO+ experiment.

Contribution

It provides the first detailed comparison of scintillation decay times and pulse shape discrimination in oxygenated and deoxygenated LAB with PPO.

Findings

Deoxygenation improves pulse shape discrimination in LAB.

Decay times differ between oxygenated and deoxygenated solutions.

Enhanced discrimination aids in background rejection for SNO+.

Abstract

The SNO+ liquid scintillator experiment is under construction in the SNOLAB facility in Canada. The success of this experiment relies upon accurate characterization of the liquid scintillator, linear alkylbenzene (LAB). In this paper, scintillation decay times for alpha and electron excitations in LAB with 2 g/L PPO are presented for both oxygenated and deoxygenated solutions. While deoxygenation is expected to improve pulse shape discrimination in liquid scintillators, it is not commonly demonstrated in the literature. This paper shows that for linear alkylbenzene, deoxygenation improves discrimination between electron and alpha excitations in the scintillator.