The effect on the scintillation efficiency of NaI(Tl) of changes in the thallium concentration and strain: II. Theoretical

A theory is developed which relates the scintillation efficiency of single crystals of NaI(Tl) and the mean specific energy loss of the exciting particle. Consideration is given in the theory to the existence of two major luminescence processes, and this is found to affect significantly the scintillation efficiency at high specific energy loss. The major energy carriers are considered to be either electrons and self-trapped holes or excitons at low specific energy loss and photons resulting from the radiative decay of excitons at high specific energy loss. The theory is compared with the experimental results reported in the preceding paper and quite good agreement is found.