An exploratory study of a tellurium-loaded liquid scintillator based on water and p-dioxane

TL;DR

This study explores a novel surfactant-free water-based tellurium-loaded liquid scintillator using water-miscible organic solvents, aiming to enhance tellurium solubility and optimize scintillation properties for neutrinoless double-beta decay experiments.

Contribution

It introduces a new water-containing, surfactant-free formulation for tellurium-loaded liquid scintillators and maps its phase behavior and optical properties, advancing detector development.

Findings

Identified homogeneous-mixture domains for tellurium loading

Measured scintillation quenching effects due to water and tellurium acid

Provided benchmarks for high-loading water-based scintillator formulations

Abstract

Tellurium-loaded liquid scintillators are critical for neutrinoless double-beta decay experiments. However, conventional organic scintillators are constrained by the limited solubility of organic tellurium compounds compared with that of inorganic ones in water, whereas water-based scintillators are likely constrained by the destabilization of surfactants caused by inorganic tellurium compounds. In this work, a surfactant-free water-containing route is explored, in which an aqueous telluric acid solution is introduced into a water-miscible organic scintillator comprising p-dioxane, naphthalene, and PPO. The phase behavior of this system is mapped to delineate homogeneous-mixture domains and to estimate practical upper bounds on tellurium loading. Optical properties are characterized by UV-visible absorption spectroscopy and fluorescence spectroscopy. The scintillation light yield is obtained with a relative method that compares to a reference LAB-PPO scintillator. The measurements demonstrate scintillation quenching induced by water and by tellurium acid. These results provide benchmarks for water-containing and surfactant-free formulations and support the development of high-loading liquid scintillators for future detector design.