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Scintillators are used not only as single crystals in radiation detection systems but also as arrays, columns, and fibers. In this study, a novel optical-guiding crystal scintillator (OCS) was fabricated using an Eu:SrI 2 crystal as the core and borosilicate glass as the cladding. The OCS has an elongated shape and can be flexibly processed like an optical fiber. Furthermore, because inorganic scintillator crystals are used as the core, the OCS has high sensitivity to high-energy radiation, such as γ- and X-ray radiation, unlike plastic scintillators. In this study, by observing the cross section of the fabricated OCS, identifying the crystal structure, and investigating the radioluminescence spectrum under X-ray irradiation, OCS fabrication in accordance with the OCS design specifications was confirmed, and the SrI 2 crystal structure and Eu2+ 5d–4f luminescence were maintained. The γ-ray responses, such as light yield and decay time, were also investigated. [ABSTRACT FROM AUTHOR]

Large-size and -scale bismuth germanate (Bi 4 Ge 3 O 12 , BGO) crystals were grown in an oxidizing atmosphere using the modified Bridgman method. Although the growth condition has been optimized, we found a few reddish crystals, resulting in poor performance. In this work, the red-color-induced characteristic absorption bands corresponding to 506, 389, and 332 nm were studied by measuring the optical transmission and absorption spectra. A modified oxygen-annealing was applied to eliminate the reddish in BGO single crystal. Based on the comparison of the optical performance, the absorption band in the visible range of the reddish crystals disappeared after annealing. This phenomenon greatly improved the light output and energy resolution. The effects of annealing in reducing atmosphere were studied. The formation mechanism of crystal coloration was also discussed. [ABSTRACT FROM AUTHOR]

Single crystal growth of undope CaCl 2 , CaBr 2 and CaI 2 was performed by Bridgman–Stockbarger (BS) method. Investigations of their crystal phases, luminescence and scintillation properties such light yield, energy resolution decay time were performed. In addition, linearity of gamma-ray response in 32–1275 keV range were also evaluated. The light output of 106,000 photon/MeV, energy resolution of 3.2%@662 keV, and scintillation decay time of 834 ns (84%) 1460 ns (16%) were observed. Luminescence properties of CaBr 2 also firstly reported. [ABSTRACT FROM AUTHOR]