| abstract |
X-ray intensifying screen based on a rare earth tantalate phosphor, and process for preparing the phosphor, said phosphor having the monoclinic M' structure and selected from: (a) YNbxTa1-xO4, where x is 0 to about 0.15; (b) LuNbxTa1-xO4, where x is 0 to about 0.2; (c) Y1-yTmyTaO4, where y is 0 to about 0.03; (d) a solid solution of (a) and (b); (e) a solid solution of (a) and (c); (f) Y1-yTbyTaO4, where y is about 0.001 to about 0.15; (g) Lu1-yTbyTaO4, where y is about 0.001 to about 0.15; (h) Gd1-yTbyTaO4, where y is about 0.001 to about 0.15; (i) a solid solution of at least two of (f), (g) and (h); (j) any of (a) to (i) wherein up to 45 mole percent of the yttrium, lutetium or gadolinium is replaced by lanthanum; (k) any of (a) to (i) wherein up to 15 mole percent of the yttrium, lutetium or gadolinium is replaced by ytterbium; and (l) any of (a), (b), (c), (d) and (e) wherein up to 15 mole percent of the yttrium or lutetium is replaced by gadolinium. |