| 摘要 |
PURPOSE:To obtain a material for a scintillator having high fluorescent intensity, by heat-treating a single crystal of a tungstic acid compound in an oxygen- containing atmosphere at a temperature within a specific range. CONSTITUTION:The single crystal of a tungstic acid compound of formula (M is Mg, Zn and/or Cd) is heated in a mixed gas atmosphere composed of oxygen (10-100vol%) and an inert gas (e.g. nitrogen gas) at a temp. between the (m.p. -200 deg.C) and m.p.,[pref. between (m.p. -200 deg.C) and (m.p. -30 deg.C)]. Oxygen atoms diffuse from the surface of the crystal into the crystal by this heat treatment, and eliminate the oxygen vacancies produced during the crystal growing process. Consequently, the absorption of the fluorescence (wavelength of max. intensity: 480nm) can be eliminated, and the fluorescent intensity of the single crystal can be improved.
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