Kyung Kwang Joo

Development of a Liquid Scintillator Using Water for a Next Generation Neutrino Experiment

A feasibility study on a new type of liquid scintillator based on water has been performed. Mainly due to the differences in polarities between water and oil, organic solvents are not mixed in water. In order to make a liquid scintillator based on water, a surfactant that contains hydrophilic and hydrophobic groups is used. The surfactant keeps water and organic solvents apart in solution. Good physical and optical parameters and long-term stability are required to use liquid scintillator based on water in massive detector for the next generation neutrino experiments. In this paper, we report the characteristics and the possibility of liquid scintillators using water with various new surfactants.

Constructing experimental devices for half-ton synthesis of gadolinium-loaded liquid scintillator and its performance

This paper describes in brief features of various experimental devices constructed for half-ton synthesis of gadolinium(Gd)-loaded liquid scintillator (GdLS) and also includes the performances and detailed chemical and physical results of a 0.5% high-concentration GdLS. Various feasibility studies on useful apparatus used for loading Gd into solvents have been carried out. The transmittance, Gd concentration, density, light yield, and moisture content were measured for quality control. We show that with the help of adequate automated experimental devices and tools, it is possible to perform ton scale synthesis of GdLS at moderate laboratory scale without difficulty. The synthesized GdLS was satisfactory to meet chemical, optical, and physical properties and various safety requirements. These synthesizing devices can be expanded into massive scale next-generation neutrino experiments of several hundred tons.

Development of the Gadolinium-loaded Liquid Scintillator Detector

In order to measure neutrino oscillation parameter θ13, gadolinium-loaded liquid scintillator is used as a neutrino target. The recipe of liquid scintillator is determined by optical and physical requirements as well as safety considerations. We develop a liquid scintillator with high flash point, easy availability and low toxicity using domestically produced linear alkyl benzene for the detection of reactor neutrino. For synthesis of gadolinium compound using carboxylic acid, we use a neutralization chemical reaction process. The gadolinium-loaded liquid scintillator dissolved in linear alkyl benzene has a long attenuation length and high light output.