Liquid Organic Scintillators for Detection of Rare Events: Methods of Purification from U, Th, and K

Problems of the development of liquid organic scintillators are discussed from the point of view of the content of radioactive impurities in detectors for recording rare events. The results of investigations of various methods for purifying individual scintillator components from U, Th, and K are presented. It is shown the PPO (2,5-Diphenyloxazole) scintillation additive, where the concentration of potassium may range between 0.8 and 7.1 g/g, is the main source of contamination with potassium ( K). In linear alkylbenzene (LAB, Russia), which is viewed as a promising dissolver for creating a large-scale neutrino detector, the measured concentration of potassium is about 10 g/g.