Preparation method of rare earth activated alkaline earth metal fluorohalide stimulable phosphor and radiographic image conversion panel

A method for preparing a rare earth activated alkaline earth metal fluorohalide stimulable phosphor represented by the following formula (I):

• Ba(1−x)M2(x)FBr(y)I(1−y):aM1, bLn, cO (I)
• wherein M1 is at least an alkali metal selected from the group consisting of Li, Na, K, Rb and Cs;
• M2 is at least an alkaline earth metal selected from the group consisting of Be, Mg, Ca and Sr;
• Ln is at least one rare earth element selected from the group consisting of Ce, Pr, Sm, Eu, Gd, Tb, Tm, Dy, Ho, Nd, Er and Yb;
• and x, y, a, b and c are values meeting the following conditions:
• 0≦x≦0.3, 0≦y≦0.3, 0≦a≦0.05 0<b≦0.2 and 0≦c≦0.1,
• the method comprising the steps of
• (a) preparing a reactant solution having a barium concentration of not less than 3.3 mol/l in a reaction vessel,
• (b) forming a precursor of the stimulable phosphor,
• (c) removing a solvent from a mother liquor,
• (d) separating the precursor from the mother liquor, and
• (e) calcining the separated precursor to make a rare earth activated alkaline earth metal fluorohalide stimulable phosphor.