Influence of the Temperature Dependence of the NaI(Tl) Decay Time Constant on NaI(Tl) Detector Applications

Pulse shape discrimination is used in important NaI(Tl) detector applications, such as, Phoswich applications, particle separation, and pile-up suppression. These applications utilizing only pulse height spectra gated by a PSD window can be compromised by temperature excursions in the detector. We present measurements of the NaI(Tl) decay time constant over the range 0°C - 24°C. A temperature variation of ~5 nsec/°C was measured. The implications of the temperature variation on detector performance are discussed.