The luminescence and scintillation properties of SrI ₂ single crystals doped with 5% Eu ²⁺ and 0.05%, 0.2% and 0.5% Sm ²⁺ are evaluated. X-ray excited and photoluminescence measurements show energy transfer from excited Eu ²⁺ ions to Sm ²⁺ ions. At a concentration of 0.5% Sm ²⁺ , the luminescence consists almost entirely of 740 nm emission from Sm ²⁺ 5d-4f transitions. Co-doping SrI ₂ :5% Eu ²⁺ with Sm ²⁺ provides a novel method to bypass the self-absorption problem encountered in large SrI ₂ :Eu ²⁺ crystals and, at the same time, provides a unique near-infrared emitting scintillator with a light yield of approximately 40,000 photons/MeV. ... Read more