Optical spectroscopy and thermoluminescence of electrolytically colored KCI:Tl+ crystals

The paper presents the spectroscopic properties of electrolytic colored KCI:Tl and KCI:Tl+Ca crystals and the assignments of the new defects which are formed during electron injection process. The new formed defects T1° and T1°+Ca 2+ with the metal in the anionic sites, presents very high photoluminescence properties in the near infrared region. Together with those centers, the F-centers, their aggregates and the holes centers are formed during electrolytic coloring process. Their properties were studied by optical absorption (OA), photoluminescence (PL) and thermoluminescence (TL) measurements and compared with those obtained by ionizing irradiation in uncolored KCI:TI crystals. The results suggest a more efficient Tl + →T1° process in the case of Ca 2+ codoped samples due to the prolonged time of electrons injection, low temperature and high electric field.