Stabilized phosphor intermediates, storage phosphors, radiation image storage panels, and preparation methods

A storage phosphor comprising the product of firing, at a temperature from about 700.degree. to 1300.degree. C., a composition of matter consisting essentially of oxosulfur reducing agent for iodine, and a combination of species characterized by the relationship:

• (Ba.sub.1-a-b-c Mg.sub.a Ca.sub.b Sr.sub.c)FX.sub.1-z I.sub.z.rM.sup.a X.sup.a :yA:eQ
• wherein
• X is selected from the group consisting of Cl and Br and combinations thereof;
• M.sup.a is selected from the group consisting of Na, K, Rb, and Cs and combinations thereof;
• X.sup.a is selected from the group consisting of F, Cl, Br, and I and combinations thereof;
• A is selected from the group consisting of Eu, Ce, Sm, and Tb and combinations thereof;
• Q is selected from the group consisting of BeO, MgO, CaO, SrO, BaO, ZnO, Al.sub.2 O.sub.3, La.sub.2 O.sub.3, In.sub.2 O.sub.3, SiO.sub.2, TiO.sub.2, ZrO.sub.2, GeO.sub.2, SnO.sub.2, Nb.sub.2 O.sub.5, Ta.sub.2 O.sub.5, and ThO.sub.2 and combinations thereof;
• a+b+c is from 0 to 0.4;
• z is from 1.times.10.sup.-4 to 1;
• r is from 1.times.10.sup.-6 to 0.1;
• y is from 1.times.10.sup.-4 to 0.1;
• e is from 1.times.10.sup.-5 to 0.1;
• and
• wherein said oxosulfur reducing agent is selected from the group consisting of Bunte compounds having the general formula R'SSO.sub.3 D, where R' is a covalently bonded organic substituent and D is a counterion, and organic and inorganic oxosulfur salts having anions of the general formula S.sub.j O.sub.k wherein 0.25<j/k<1.0;
• and wherein said oxosulfur reducing agent is present prior to said firing in a molar ratio of sulfur to alkaline earth metal of greater than 1.times.10.sup.-4 and less than 0.020.

A radiographic image storage panel comprising a support and a fluorescent layer including phosphor crystals capable of absorbing X-radiation and emitting longer wavelength electromagnetic radiation in response to stimulating radiation of a third wavelength, said phosphor crystals consisting essentially of the product of firing, at a temperature from about 700.degree. to 1300.degree. C., a combination of species characterized by the relationship:

• MFX.sub.1-z I.sub.z.uM.sup.a X.sup.a :yA:eQ:tD
• wherein
• M is selected from the group consisting of Mg, Ca, Sr, and Ba and combinations thereof;
• X is selected from the group consisting of Cl and Br and combinations thereof;
• M.sup.a is selected from the group consisting of Na, K, Rb, and Cs and combinations thereof;
• X.sup.a is selected from the group consisting of F, Cl, Br, and I and combinations thereof;
• A is selected from the group consisting of Eu, Ce, Sm, and Tb and combinations thereof;
• Q is selected from the group consisting of BeO, MgO, CaO, SrO, BaO, ZnO, Al.sub.2 O.sub.3, La.sub.2 O.sub.3, In.sub.2 O.sub.3, SiO.sub.2, TiO.sub.2, ZrO.sub.2, GeO.sub.2, SnO.sub.2, Nb.sub.2 O.sub.5, Ta.sub.2 O.sub.5, and ThO.sub.2 and combinations thereof;
• D is selected from the group consisting of V, Cr, Mn, Fe, Co, and Ni and combinations thereof;
• z is from 1.times.10.sup.-4 to 1;
• u is from 0 to 1;
• y is from 1.times.1.times.10.sup.-4 to 0.1;
• e is from 0 to 1;
• and
• t is from 0 to 1.times.10.sup.-2 ;
• and oxosulfur reducing agent for iodine,
• wherein said oxosulfur reducing agent for iodine is present in said combination of species in an amount sufficient to increase relative photostimulated luminescence intensities relative to the phosphor defined above absent said reducing agent for iodine.

A method for preparing a radiographic storage phosphor comprising

• dispersing in an aqueous solvent an oxosulfate reducing agent for molecular iodine and a plurality of precursor compounds having the total elemental composition of a phosphor selected from the group consisting of divalent alkaline earth metal fluorohalide phosphors containing iodine which satisfy the relationship:
• MFX.sub.1-z I.sub.z.uM.sup.a X.sup.a :yA:eQ:tD
• wherein
• M is selected from the group consisting of Mg, Ca, Sr, and Ba and combinations thereof;
• X is selected from the group consisting of Cl and Br and combinations thereof;
• M.sup.a is selected from the group consisting of Na, K, Rb, and Cs and combinations thereof;
• X.sup.a is selected from the group consisting of F, Cl, Br, and I and combinations thereof;
• A is selected from the group consisting of Eu, Ce, Sm, and Tb and combinations thereof;
• Q is selected from the group consisting of BeO, MgO, CaO, SrO, BaO, ZnO, Al.sub.2 O.sub.3, La.sub.2 O.sub.3, In.sub.2 O.sub.3, SiO.sub.2, TiO.sub.2, ZrO.sub.2, GeO.sub.2, SnO.sub.2, Nb.sub.2 O.sub.5, Ta.sub.2 O.sub.5, and ThO.sub.2 and combinations thereof;
• D is selected from the group consisting of V, Cr, Mn, Fe, Co, and Ni and combinations thereof;
• z is from 1.times.10.sup.-4 to 1;
• u is from 0 to 1;
• y is from 1.times.10.sup.-4 to 0.1;
• e is from 0 to 1;
• and
• t is from 0 to 1.times.10.sup.-2 ;
• wherein said oxosulfur reducing agent for iodine is present with said precursor compounds in a molar ratio of sulfur to alkaline earth metal of greater than 1.times.10.sup.-4 and less than 0.020;
• said plurality of precursor compounds yielding said phosphor as a product of firing;
• drying said dispersion;
• and
• firing the product of said drying, said firing being at a temperature from about 700.degree. to 1300.degree. C.

A method for preparing a stabilized radiographic phosphor intermediate comprising dispersing in an aqueous solvent an oxosulfate reducing agent and a plurality of precursor compounds having the total elemental composition of a phosphor selected from the group consisting of divalent alkaline earth metal fluorohalide phosphors containing iodine which satisfy the relationship:

• MFX.sub.1-z I.sub.z.uM.sup.a X.sup.a :yA:eQ:tD
• wherein
• M is selected from the group consisting of Mg, Ca, Sr, and Ba and combinations thereof;
• X is selected from the group consisting of Cl and Br and combinations thereof;
• M.sup.a is selected from the group consisting of Na, K, Rb, and Cs and combinations thereof;
• X.sup.a is selected from the group consisting of F, Cl, Br, and I and combinations thereof;
• A is selected from the group consisting of Eu, Ce, Sm, and Tb and combinations thereof;
• Q is selected from the group consisting of BeO, MgO, CaO, SrO, BaO, ZnO, Al.sub.2 O.sub.3, La.sub.2 O.sub.3, In.sub.2 O.sub.3, SiO.sub.2, TiO.sub.2, ZrO.sub.2, GeO.sub.2, SnO.sub.2, Nb.sub.2 O.sub.5, Ta.sub.2 O.sub.5, and ThO.sub.2 and combinations thereof;
• D is selected from the group consisting of V, Cr, Mn, Fe, Co, and Ni and combinations thereof;
• z is from 1.times.10.sup.-4 to 1;
• u is from 0 to 1;
• y is from 1.times.10.sup.-4 to 0.1;
• c is from 0 to 1;
• and
• t is from 0 to 1.times.10.sup.-2 ;
• wherein said oxosulfur reducing agent for iodine is present with said precursor compounds in a molar ratio of sulfur to alkaline earth metal of greater than 1.times.10.sup.-4 and less than 0.020.

A stabilized radiographic phosphor intermediate comprising an oxosulfate reducing agent and a plurality of precursor compounds having the total elemental composition of a phosphor selected from the group consisting of divalent alkaline earth metal fluorohalide phosphors containing iodine which satisfy the relationship:

• MFX.sub.1-z I.sub.z.uM.sup.a X.sup.a :yA:eQ:tD
• wherein
• M is selected from the group consisting of Mg, Ca, Sr, and Ba and combinations thereof;
• X is selected from the group consisting of Cl and Br and combinations thereof;
• M.sup.a is selected from the group consisting of Na, K, Rb, and Cs and combinations thereof;
• X.sup.a is selected from the group consisting of F, Cl, Br, and I and combinations thereof;
• A is selected from the group consisting of Eu, Ce, Sm, and Tb and combinations thereof;
• Q is selected from the group consisting of BeO, MgO, CaO, SrO, BaO, ZnO, Al.sub.2 O.sub.3, La.sub.2 O.sub.3, In.sub.2 O.sub.3, SiO.sub.2, TiO.sub.2, ZrO.sub.2, GeO.sub.2, SnO.sub.2, Nb.sub.2 O.sub.5, Ta.sub.2 O.sub.5, and ThO.sub.2 and combinations thereof;
• D is selected from the group consisting of V, Cr, Mn, Fe, Co, and Ni and combinations thereof;
• z is from 1.times.10.sup.-4 to 1;
• u is from 0 to 1;
• y is from 1.times.10.sup.-4 to 0.1;
• e is from 0 to 1;
• and
• t is from 0 to 1.times.10.sup.-2 ;
• wherein said oxosulfur reducing agent for iodine is present with said precursor compounds in a molar ratio of sulfur to alkaline earth metal of greater than 1.times.10.sup.-4 and less than 0.020.