Silver admixture effect on luminescence properties of CdI2 scintillators

S.S.Novosad, A.B.Lyskovich, Ya.A.Pastyrski, B.M.Kostyuk

I.Franko Lviv State University, 1 Universitetska Str., 79608 Lviv, Ukraine

Received August 15, 1998; in final form, March 3, 1999

The CdI2, CdI2:Cd and CdI2:Ag luminescence characteristics comparison has shown that under CdI2 activation with Ag+, the Ag- Cd centers are formed, their effective negative charges being compensated by neighboring VI+ anion vacancies. Ag-CdVI+ impurity-vacancy complexes and Cdi 0 interstitial atoms are assumed to form associates, which are emission recombination centers. At low temperatures, near-activator exciton luminescence arises at 520 nm due to the free electron recombination with holes localized on halide ions in the neighborhood with Ag+ ions. CdI2:Ag recombination luminescence in the 670-680 nm band is associated with alpha-centers. A high-temperature luminescence quenching of these centers is due to ionic and photochemical processes.

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