Investigation of Light Collection in Scintillation Cubes of the SFGD Detector

This paper presents the results of measuring the parameters of scintillation cubes, which are elements of the active target of the upgraded near detector of the T2K experiment, with the scintillation of a polystyrene-based organic scintillator being excited by an ultraviolet LED. Most attention is paid to the study of light leaks through the side faces of the cubes. The measurement results show that an average value of the coefficient characterizing light leaks through one face of the cube is 0.026. The effect of heating scintillation cubes on the light collection from them and light leaks are studied. After keeping the cubes at a temperature of 60°C for 72 h, the light collection from the cubes and the light leaks remained at the same level.