| 摘要 |
PROBLEM TO BE SOLVED: To raise the luminescent efficiency of an X-ray phosphor while weakening the afterglow component. SOLUTION: This X-ray phosphor is represented by the formula: LnMBDO4 : R<3+> , emits light when excited by X-rays, and is obtd. by baking a mixture comprising 1 g-atom of an element represented by D and 1 g-atom of the sum of elements represented by Ln, M, R, and B. In the formula, Ln is at least one element selected from among Y, Gd, La, and Lu; M is at least one divalent metal selected from among Be, Mg, Ca, Sr, Ba, Zn, and Cd; B is boron; D contains at least either Ta or Nb; and R<3+> is an activator and is Tm, Gd, Ce, Pr, Sm, Eu, Tb, Dy, or Yb or self-activation. The contents of R<3+> , M, and B, based on 1 g-atom of D, are 1×10<-5> -3×10<-1> , 1×10<-5> -6×10<-1> , and 1×10<-5> -5×10<-1> , respectively.
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