Comparative study of nondoped and Eu-doped SrI2 scintillator

Abstract

Optical and scintillation properties of nondoped and Eu 3% doped SrI 2 crystals grown by the Vertical Bridgman method were investigated. Eu-doped crystal showed an intense single band emission at 430 nm due to the Eu 2+ 5d-4f transitions in both photoluminescence and scintillation while the nondoped crystal had a complex spectral shape. The latter emission consists of mainly four bands: 360 nm, 540 nm, 410 nm and 430 nm. The origins of 360 nm and 540 nm were self-trapped exciton and unexpected impurity, respectively. The origins of 410 and 430 nm lines were ascribed to F center in different I sites. Under 137 Cs -ray irradiations, both crystals showed a clear photoabsorption peak. The scintillation light yields of the nondoped and Eu-doped SrI 2 resulted 33000 ph/MeV and 82000 ph/MeV, respectively. The energy resolution at 662 keV of Eu-doped was 4% while that of the non-doped SrI 2 was 8%.

Inorganic scintillating materials and scintillation detectors

“…Figure 8 summarizes the R&D history of common scintillators. Among these scintillators, the author contributed to develop GYAG, 37) GAGG, 36) Eu:SrI 2 38) and LiCaAlF 6 . 39,40) The recent trend is to develop host materials of complex compositions, and the combination of an insulator host and a doped emission center has become a standard approach to achieve higher performance.…”

“…A common example is Nd-doped LaF 3 , which has an emission wavelength at 175 nm with a few-ns decay time 77) due to the 5d-4f transition of Nd 3+ . Divalent Eu can also show a very high scintillation light yield with typically a 1 µs decay time; example scintillators are Eu 2+ -doped SrI 2 , 38) CaF 2 , 31) LiI 78) and LiCaAlF 6 . 40) Recently, luminescence due to the 5d-4f transitions of Sm 2+ ions was also reported, 79–81) and investigations are in progress.…”

“…Following these pioneering investigations, numerous researchers started to investigate many halide materials as potential scintillators, and some new materials were found. Among these newly developed scintillators, Eu-doped SrI 2 19,38,115) became a commercial product for γ-ray detectors. Actually, Eu-doped SrI 2 was invented in the mid-20th century, 116) but no one paid any continuous attention on this material, possibly due to its featureless properties.…”

“…Scintillation spectra of Nd 3+ -, Er 3+ - and Tm 3+ -doped LuF 3 , 82) Ce-doped GAGG, 36) Pr-doped LuAG, 75) Eu-doped SrI 2 38) and Sm-doped FCZ glass-ceramics. 79) …”

Comparative Studies of Scintillation Properties of Tl-based Crystals

“…Recently, halide materials have attracted much attention for scintillator applications since they have a relatively narrower bandgap than oxide and nitride materials, and a narrow bandgap is advantageous for scintillators based on conventional Robbins (19) and some empirical (20,21) models. On the basis of these models, many halide scintillators have been developed, (22)(23)(24)(25)(26)(27)(28)(29)(30) and some of them can reach the production stage in some companies. (22)(23)(24) Among such halide materials, Tl-based crystalline materials have shown excellent scintillation properties such as high light yield and energy resolution.…”