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arXiv · physics/0605248

Temperature behavior of NaI (Tl) scintillation detectors

K. D. Ianakiev·B. S. Alexandrov·P. B. Littlewood·M. C. Browne
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Abstract

It is a familiar fact that the total measured light yield of NaI (Tl) detectors is a nonlinear function of temperature. Here we present new experimental data for the temperature behavior of doped NaI(Tl) scintillators that instead shows a linear dependence of light output over a wide temperature range- including that for outdoor applications. The shape of the light pulse shows in general two decay processes: a single dominant process above room temperature and two decay time constants below. We show that redistribution of the intensities is temperature-dependent; the second (slow) decay component is negligible at room temperatures, but, by -20C, it contributes up to 40 percents of the total light and has a duration of several microseconds. We discuss the profound effect this new understanding of the light output has on the pulse height analysis instrumentation. We introduce a theoretical model to explain the experimental results. In addition, we describe a unique technique for correcting both amplitude and shape temperature changes inside the NaI(Tl) detector package.

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K. D. Ianakiev, B. S. Alexandrov, P. B. Littlewood, M. C. Browne. 2006-05-30. Temperature behavior of NaI (Tl) scintillation detectors. https://doi.org/10.1016/j.nima.2009.02.019

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