Characterization of mixed halide scintillators: CsSrBrI2:Eu, CsCaBrI2:Eu and CsSrClBr2:Eu

• DOI: 10.1016/j.jlumin.2018.10.108
• Publication Date: 2018-10-26T11:51:53Z
• Authors: L. Stand; M. Zhuravleva; B. Chakoumakos; H. Wei; J. Johnson; V. Martin; M. Loyd; D. Rutstrom; W. McAlexander; Y. Wu; M. Koschan; C.L. Melcher
• Keywords: Orthorhombic crystal system; Microsecond; Europium; Crystal (programming language)

Abstract Eu2+-doped mixed halide scintillators, CsSrBrI2, CsCaBrI2 and CsSrClBr2 were studied for gamma-ray spectroscopy applications. We grew O13 mm single crystals via the vertical Bridgman method using a self-seeded technique and investigated physical and scintillation properties. Single crystal X-ray diffraction and thermal analysis reveal that CsSrBrI2 and CsSrClBr2 have orthorhombic crystal structures and melt congruently at 611 °C and 752 °C, respectively, while CsCaBrI2 has a cubic structure and melts congruently at 671 °C. All three compounds have the typical Eu2+ 5d – 4 f single-peak emission centered between 445 and 462 nm with a scintillation decay time of a few microseconds. The optimal Eu2+ concentration to maximize the scintillation light yield was determined to be ~7–10%. All three mixed scintillators have an improved energy resolution compared to the non-mixed CsSrI3:Eu, CsCaI3:Eu and CsSrBr3:Eu. The best performing scintillator is CsSrBrI2:Eu 7% with light yield of 65,300 ph/MeV and energy resolution of 3.4% at 662 keV. Excellent proportional response for a wide range of gamma-ray energies was measured for all three scintillators.