Effects of Na and K co-doping on growth and scintillation properties of Eu:SrI2 crystals

• Na or K co-doped Eu:SrI2crystals were grown by the modified μ-PD method.
• The milky parts were generated in the Na5.0% and K5.0%,Eu:SrI2crystals.
• The light yield of Eu:SrI2was decreased by the Na or K co-doping.
• The decay times of Eu:SrI2were almost constant by the Na or K co-doping.
• The non-proportionalitywas improved in the low energy region by the K co-doping.

We grew Na and K co-doped Eu:SrI2 [Na,Eu:SrI2 and K,Eu:SrI2] crystals by a modified micro-pulling-down method to reveal the co-doping effects on the crystal growth and scintillation properties. The non-codoped, Na0.5%, Na1.0%, K0.5% and K1.0%,Eu:SrI2 crystals indicated high transparency while the milky parts were generated in the Na5.0% and K5.0%,Eu:SrI2 crystals. The light yields of Na,Eu:SrI2 and K,Eu:SrI2 crystals under γ-ray irradiation were decreased by the Na and K co-doping. On the other hand, there was a small change within 940–1020 ns in the decay times by the Na and K co-doping. In the light yield proportionality under γ-ray irradiation, the non-proportionality in the low energy region was improved by Na and K co-doping.