Radiation defects creation in CsI(Tl) crystals and their luminescence properties

Radiation defect creation processes in CsI(Tl) crystals have been studied. The model of color center, according to which Tl0 is close to anionic vacancy, is considered. The absorption spectrum of Tl0Va+-center is a superposition of bands responsible for both transitions between the near activator exciton states and for those between the valent electron states in thallium atom perturbed by the anionic vacancy. Another center Tl+Va+ may appear as a result of the Tl0Va+ photoionization. Absorption bands at 3.44, 3.8, 2.64 eV of the electron trapping Tl+Va+ in the center have exciton origin. Tl+Va+ is also a luminescence center. The excitation in the absorption bands of this center luminescence is conditioned by the luminescence of the near activator excitons.