SCINTILLATION-COUNTERS CHARACTERISTICS VERSUS LIGHT COLLECTION CONDITIONS

The effect of the light collection conditions on a scintillation count er's performance have been studied by measuring the characteristics of a counter with a rectangular plastic scintillator surrounded by air, water, and paraffin oil, and those of a counter with trapezium scintil lators with angles between side faces of 5.6, 7.5, and 10-degrees. The measurements demonstrate that the time resolution is mainly defined b y a number of collected photons. When the refraction index of the envi ronment rises, the effective light propagation velocity towards the PM T rises. It is possible to select an angle between the faces of a trap ezium scintillator at which the detected signal amplitude is virtually independent of the scintillation site.