Speaker
Description
Long-term stability of liquid scintillators (LSs) is essential for maintaining reliable detector performance in neutrino experiments. The addition of diisopropylnaphthalene (DIN) to conventional linear alkylbenzene (LAB)-based scintillators can enhance pulse shape discrimination (PSD) and improve neutron-background rejection. We investigated the long-term stability of a gadolinium-loaded liquid scintillator containing 10% DIN under normal laboratory storage conditions. The relative light yield and PSD performance were monitored for approximately 650 and 600 days, respectively, while the optical transmittance was remeasured after approximately 500 days. Environmental stress tests were also conducted to evaluate the effects of air exposure, nitrogen purging, heating, and high humidity. Under normal storage conditions, no observable degradation was found in the optical transmittance, relative light yield, or PSD performance. Among the tested stress conditions, high humidity produced the largest reduction in relative light yield, approximately 7%, whereas the other samples remained consistent with their initial measurements within uncertainties. These results demonstrate that the 10% DIN-containing Gd-LS provides stable optical and scintillation performance suitable for long-term operation in neutrino detectors.