SINGLE-CRYSTALS FOR RADIATION DETECTORS

Recent Progress in crystal growth technology is described for typical alkali (alkali-earth) halide and oxide scintillation crystals such as NaI:Tl, CsI:Tl, bismuth germanate (BGO; Bi4Ge3O12). cadmium tungstate (CWO; CdWO4), and cerium-doped gadolinium silicate (GSO:Ce; Gd2SiO5:Ce). Characteristics of the above as well as some other scintillation crystals are briefly surveyed including radiation damage. These scintillators have found a variety of applications as X-ray and gamma-ray detectors due to large absorption coefficient (high Z), large light output and relatively short decay time of luminescence. Typical applications in X-ray CT (CWO, etc.), Positron Emission CT (BGO, etc.), nuclear well logging, nuclear as well as high energy physics experiments (BGO, CsI:Tl, CsI, BaF2, etc.), etc. are reviewed. GSO:Ce seems to have overall excellent characteristics, although it has been established just in recent years and hence has not yet become practical very widely. R & D efforts for new fast, dense and radiation hard scintillation crystals such as CeF3. PbF2, CdF2, etc. are in progress.