Development of BSO (Bi 4Si 3O 12) crystal for radiation detector

• Published in: Optical materials 2002-02, Vol.19 (1), p.201-212
• Main Authors: Ishii, M, Harada, K, Hirose, Y, Senguttuvan, N, Kobayashi, M, Yamaga, I, Ueno, H, Miwa, K, Shiji, F, Yiting, F, Nikl, M, Feng, X.Q
• Format: Article
• Language: English
• Subjects: Exact sciences and technology; Experimental methods and instrumentation for elementary-particle and nuclear physics; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Nuclear physics; Physics; Radiation detectors, dosimeters; Scintillation detectors; X- and γ-ray instruments and techniques; X- and γ-ray sources, mirrors, gratings and detectors
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/S0925-3467(01)00220-8

Colorless and crack-free single crystals of bismuth silicate (Bi 4Si 3O 12, BSO) scintillators have been grown by the vertical Bridgman method. Some segregation phases have been found to form on the surface and at the top of the crystals grown from both stoichiometric and off-stoichiometric melt compositions. The excitation and emission spectra are similar to BGO. The light output is 20% of BGO, giving energy resolution of 32% for 662 keV γ-rays ( 137Cs). The decay constants are 2.4 ns (for 6% of intensity), 26 ns (12%) and 99 ns (82%). The radiation hardness against 60Co γ-rays was found about 10 5–10 6 rad at the emission peak of 480 nm for undoped and it was almost negligible up to 10 7 rad for 0.2 at.% Ce doped crystals. We have also achieved a considerable improvement in the growth of large size crystals, offering the possible application in γ-ray detectors at high energies. Clear blocks with transverse/longitudinal dimensions as large as 25 mm/200 mm were produced with good reproducibility. The pulse height uniformity along the longitudinal axis is within ±2%. The scintillation characteristics are similar to those of small crystals.