Scintillator compositions of alkali and rare-earth tungstates

Claim 1

A scintillator composition consisting of a tungstate having a formula of AD(WO 4 ) n , wherein A is at least one element selected from group consisting of Na, K, Rb, and Cs; D is a single element selected from the group consisting of Y, La, Gd, and Lu; and n is greater than or equal to 2; and wherein said scintillator composition is doped with Ca 2+ ion in an amount from about 2 to about 500 mole per million.

Claim 20

A method for producing an alkali- and rare earth-containing scintillator composition, said method comprises the steps of: (1) providing amounts of: (a) oxygen-containing compounds of at least one alkali metal selected from the group consisting of Na, K, Rb, and Cs, (b) oxygen-containing compounds of at least one rare-earth element selected from the group consisting of Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, and (c) at least one oxygen-containing compound of tungsten; (2) mixing together the compounds to form a mixture; (3) mixing at least one halide of an element selected from the group consisting of Na, K, Rb, Cs, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu in said mixture in a quantity sufficient to act as flux during a firing; said halide being present in a range from about 0.001 to about 2 mole percent; and (4) firing the mixture under an oxygen-containing atmosphere at a temperature and for a time sufficient to convert the mixture to a solid alkali- and rare earth-containing tungstate; wherein said amounts of oxygen-containing compounds are chosen to obtain the final desired composition of said alkali- and rare earth-containing tungstate.

Claim 21

A method for producing an alkali- and rare earth-containing scintillator composition, said method comprises the steps of: (1) providing amounts of: (a) oxygen-containing compounds of at least one alkali metal selected from the group consisting of Na, K, Rb, and Cs, (b) oxygen-containing compounds of at least one rare-earth element selected from the group consisting of Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, and (c) at least one oxygen-containing compound of tungsten; (2) mixing together the compounds to form a mixture; (3) mixing at least one halide of an element selected from the group consisting of Na, K, Rb, Cs, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu in said mixture in a quantity sufficient to act as flux during a firing; said halide being present in a range from about 0.001 to about 2 mole percent; and (4) firing the mixture under an oxygen-containing atmosphere at a temperature and for a time sufficient to convert the mixture to a solid alkali- and rare earth-containing tungstate; wherein said amounts of oxygen-containing compounds are chosen to obtain the final desired composition of said alkali- and rare earth-containing tungstate.

Claim 24

A method for producing an alkali- and rare earth-containing scintillator composition, said method comprises the steps of: (1) preparing a first solution from amounts of: (a) compounds of at least one alkali metal selected from the group consisting of Na, K, Rb, and Cs, (b) compounds of at least one rare-earth element selected from the group consisting of Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, and (c) at least one compound of tungsten; (2) providing a second solution selected from the group consisting of hydroxides of at least one element selected from the group consisting of Na, K, Rb, and Cs and alkyl esters of a dicarboxylic acid selected from the group consisting of oxalic acid, malonic acid, succinic acid, and glutaric acid; (3) mixing together said first solution and said second solution to form a precipitate mixture of oxygen-containing compounds of at least one alkali metal, at least one rare-earth metal, and tungsten; (4) separating said precipitate mixture from a supernatant liquid; (5) drying said separated precipitate mixture; and (6) firing said dried precipitate mixture at a temperature for a time sufficient to convert said dried precipitate mixture to an alkali- and rare earth-containing tungstate scintillator; wherein said amounts of compounds are chosen to obtain the final desired composition of said alkali- and rare earth-containing tungstate.

Claim 25

A method for producing an alkali- and rare earth-containing scintillator composition, said method comprises the steps of: (1) preparing a first solution from amounts of: (a) compounds of at least one alkali metal selected from the group consisting of Na, K, Rb, and Cs, (b) compounds of at least one rare-earth element selected from the group consisting of Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, and (c) at least one compound of tungsten; (2) providing a second solution selected from the group consisting of hydroxides of at least one element selected from the group consisting of Na, K, Rb, and Cs and alkyl esters of a dicarboxylic acid selected from the group consisting of oxalic acid, malonic acid, succinic acid, and glutaric acid; (3) mixing together said first solution and said second solution to form a precipitate mixture of oxygen-containing compounds of at least one alkali metal, at least one rare-earth metal, and tungsten; (4) separating said precipitate mixture from a supernatant liquid; (5) drying said separated precipitate mixture; and (6) firing said dried precipitate mixture at a temperature for a time sufficient to convert said dried precipitate mixture to an alkali- and rare earth-containing tungstate scintillator; wherein said amounts of compounds are chosen to obtain the final desired composition of said alkali- and rare earth-containing tungstate.