Concentration dependence of the light yield and energy resolution of NaI:Tl and CsI:Tl crystals excited by gamma, soft X-rays and alpha particles

Based on the analysis of light yield dependence on activator concentration for NaI:Tl and CsI:Tl excited by γ-rays, soft X-rays and α-particles, an explanation of the effect of energy resolution enhancement with the rise of Tl content has been proposed. Based on the concept regarding the electron track structure, we proposed an alternative explanation of the intrinsic resolution value. The concept does not take into account the non-proportional response to electrons of different energies and is based on the statistic fluctuation of scintillation photon number formed outside and inside the regions of higher ionization density.