Determination of Henry's law coefficient of oxygen in LAB for JUNO

Abstract

Abstract The Jiangmen Underground Neutrino Observatory (JUNO) requires that the detector use liquid scintillator with an extremely low background to achieve the desired measurement accuracy of neutrino mixing parameters. In addition, the production process of the liquid scintillator must avoid radon gas contamination caused by equipment leakage. Direct measurement of radon gas in liquid scintillator is an option for system leak detection. However, considering the low percentage of radon gas and high percentage of oxygen in air, the measurement of oxygen in liquid scintillator will have higher sensitivity. Based on Henry's law and the measuring principle of a dissolved oxygen meter, an experimental device is designed to measure Henry's law coefficient and calibrate the dissolved oxygen meter. Henry's law coefficient of oxygen in linear alkylbenzene (LAB) at 23.6 °C derived from an experimental measurement is 2.09 × 107 ± 2.54 × 106 Pa·L·mol-1. The feasibility of using a dissolved oxygen meter to measure the dissolved oxygen content in LAB is verified by calibrating the dissolved oxygen meter.