Temperature effect on response function, energy resolution and light output of NaI(Tl) and bismuth germinate oxide scintillators

Due to the importance of the effect of temperature variation on the scintillation parameters, such as the light output, energy resolution and scintillation efficiency, we intended to verify the temperature effect on the response function of the Bismuth Germinate Oxide and NaI(Tl) scintillators. For the gamma ray and charged particles detection, scintillators such as Bismuth Germinate Oxide and Sodium Iodide activated by Thallium (NaI(Tl)) are widely used. Thus the effect of temperature variation on the scintillation efficiency, light output and energy resolution have been measured using both Bismuth Germinate Oxide and NaI(Tl) scintillators of φ2''x2and φ3x3dimensions in the energy range of 600-1400 keV, and at the temperature ranging from -30degC to + 70degC. Since the photomultiplier tubes tubes and scintillators are connected together, it is rather difficult to study the temperature effect on the scintillator alone, so the effect of temperature change on the photomultiplier tubes+scintillators was studied first. A similar study for the photomultiplier tube alone has been performed in a different experiment. By increasing the temperature, the scintillator efficiency and the light output decrease and the energy resolution deteriorate, whereas by decreasing the temperature, the light output and the scintillator efficiency increase and the energy resolution will improve.