Radiation-defect creation in Tl-doped crystals was studied. A model for the color center was considered, according to which the Tl0 was close to an anionic vacancy. The absorption spectrum of the Tl0Va+-center comprised a superposition of the bands which were responsible for transitions between the near activator exciton states and for those between electron states in Tl atoms that were perturbed by an anionic vacancy. Another center, Tl+Va+, could appear as a result of Tl0Va+ photo-ionization. Absorption bands (3.44, 3.8, 2.64eV) of the electron trapping Tl+Va+ in the center had an excitonic origin. The Tl+Va+ was also a luminescence center. Excitation in the absorption bands of this center luminescence was affected by the luminescence of the near activator excitons.

Radiation Defect Creation in CsI(Tl) Crystals and their Luminescence Properties. L.N.Trefilova, T.Charkina, A.Kudin, N.Kosinov, L.Kovaleva, A.Mitichkin: Journal of Luminescence, 2003, 102-103, 543-50