LUMINESCENT PROPERTIES OF FROZEN ORGANIC SCINTILLATORS

Temperature dependence of the light yield of 1-methylnaphthalene based scintillators emitting in the green spectral range was studied in the liquid and frozen states. The light yield of the scintillator frozen at -120 degrees C in vacuum increased 2.2-3.3 times compared to the ro om-temperature value in air, and reached 88-118% of the level for anth racene. All scintillators cooled to -120 degrees C, and then heated to 20 degrees C exhibited a hysteresis in the temperature variation of t he light yield. The duration of signals from the frozen samples in air was somewhat longer compared to that at room temperature. The light y ield of scintillators studied was sensitive to the ionization density.