GADOLINIUM-ACTIVATED YTTIRIUM TANTALAE FLUORESCENT SUBSTANCE, RADIATION SENSITIZED SCREEN, ASSEMBLY OF RADIATION-SENSITIZED SCREEN WITH SILVER HALIDE PHOTOGRAPHIC MATERIAL AND FORMATION OF RADIATION IMAGE

摘要

PROBLEM TO BE SOLVED: To obtain the subject fluorescent substance improved in luminous intensity by combining yttrium tantalate with gadolinium and aluminum in a specific compositional ratio. ;SOLUTION: This fluorescent substance composition is represented by the compositional formula: YTaO₄:xGd, yAl [(x) is 0(x)≤0.1; y is 1×10^-4≤(y)≤0.1, preferably 0.001≤(y)≤0.05, more preferably 0.01≤(y)≤0.03]. The fluorescent substance can be produced by adding lithium fluoride or lithium oxide as a flux to tantalum oxide, yttrium oxide, gadolinium oxide and alumimum oxide, sufficiently mixing the compounds while mechanically stirring the compounds, filling the resultant mixture in a heat-resistant vessel such as a quartz boat, an alumina crucible or a quartz crucible, placing the resultant vessel in a furnace core of an electric furnace and carrying out the baking at 1,100-1,300°C.;COPYRIGHT: (C)1999,JPO