Safe liquid scintillators for large scale detectors

TL;DR

This paper reviews the development of safe liquid scintillators with high flash points and low toxicity, suitable for large-scale neutrino detectors in sensitive environments, highlighting polysiloxane-based options.

Contribution

It introduces and compares high flash point, environmentally safer scintillators, especially polysiloxane-based, for large-scale particle physics experiments.

Findings

Polysiloxane scintillators exhibit outstanding safety properties.

High flash point solvents maintain good optical performance.

Safer scintillators are suitable for underground and nuclear reactor environments.

Abstract

Many experiments in particle physics, in particular in the field of neutrino searches, rely on organic liquid scintillators as target and detection material. The size of these detectors was continously growing in the last decades, up to the kiloton scale. In several cases these detectors are located at sites with enhanced safety requirements as underground laboratories or in the vicinity of nuclear reactors. Therefore, there is strong demand in liquids which are safe with respect to aspects as fire protection, human health or environmental pollution. In particular, properties as the flash point, the vapor pressure or the toxicity need to be significantly improved as compared to classical solvents such as xylene or pseudocumene. We present and compare the performance and optical properties of scintillators based on high flash point solvents. In particular polysiloxane based scintillators are characterized by outstanding properties in terms of safety.