Crystal growth and characterization of europium doped KCaI3, a high light yield scintillator

Effects of increasing size and changing europium activator concentration in KCaI3 scintillator crystals

“…As described in [1], fused silica ampoules at Ø22 mm ID were directly loaded with a total charge mass of 60g using commercially available anhydrous KI, CaI 2 , and EuI 2 of 4-5N purity in beaded form and heated to 200-250°C under vacuum to rid the precursors of any trace moisture prior to sealing with a torch. The crystals are grown from a randomly oriented seed formed in a bent capillary at the base of the ampoule.…”

“…New ternary compounds with similar performance have been discovered and are in various stages of development which aim to provide similar capability as well as a cost reduction, thereby promoting their more widespread use. In our research for novel and useful scintillator materials, KCaI 3 :Eu has been shown to possess highly desirable performance attributes such as light yield over 70,000 ph/MeV and energy resolution of ≈ 3% at 137 Cs decay energy of 662 keV [1].…”

Defect Engineering by Codoping in KCaI3:Eu2+ Single-Crystalline Scintillators

“…For noncodoped KCaI 3 :Eu 2+ , the RL emission maximum at 470 nm is associated with Eu 2+ 5d-4f de-excitation, consistent with the previously reported result. 12 Only a slight blueshift of Eu 2+ 5d-4f emission is observed in the codoped samples. …”

“…The noncodoped sample has an energy resolution of 6.3% at 122 keV and 3.25% at 662 keV, close to the reported values. [12] With Y 3+ , Gd 3+ , or La 3+ codoping, the energy resolutions become much worse, such as 4-7% at 662 keV and 8-12% at 122 keV. For Sc 3+ codoped samples, an energy resolution of 3.4% at 662 keV and 6.6% at 122 keV still can be obtained in the 0.1 at% Sc 3+ codoped sample, but it is degraded to 7.8% at 662 keV and 12% at 122 keV when the Sc 3+ content is increased to 0.5 at%.…”

“…Among these materials, KCaI 3 :Eu 2+ has the best performance with respect to light yield and energy resolution. [12] By using Sr 2+ -alloying, the afterglow level in KCaI 3 :Eu 2+ was decreased and attributed to the reduced melting point, but the suppression effect is quite limited. [13] In this work, the afterglow is reduced by orders of magnitude by a codoping strategy, and the physical explanation is proposed from experimental and theoretical insights.…”