| 摘要 |
PURPOSE:To provide a single crystal for a scintillator most suitable for an X-ray tomogram photography in a point of an X-ray detecting sensitivity, a light emitting wave length and an afterglow property comprising zinc tungstate of which absorption coefficient is below specific value. CONSTITUTION:A ZnWO4 crystal of which absorption coefficient is below 1.8cm<-1> at 520nm wave length and a main impurity is Si and Ca as well as an impurity content is below 500ppm is used as a scintillator crystal for converting radioactive rays such as X-rays, gamma-rays or the like into light. This crystal is prepared by a Czochralski method or a zone melting method and, in a Czochralski method, an electric field is applied so as to make a crystal side negative and a melt wave side positive. |
