METHOD OF PREPARING CALCIUM TUNGSTATE X-RAY LUMINOPHOR Russian patent published in 2003 - IPC

FIELD: x-ray diagnostic methods. SUBSTANCE: calcium tungstate is precipitated from aqueous solution of calcium chloride and sodium tungstate, to which 0.5 to 10 vol % dimethylformamide is added., and precipitate is washed. To calcium tungstate precipitate is added demineralized water and calcium chlorides to give blend containing CaWO₄-94-99.5% and 0,5-6.0% CaCl₂ (mineralizer). Blend is dried at 140 C to dusting, loaded into quartz pot, and calcined for 1 h in air at 900 C. Cooled luminophor is rinsed with demineralized water, dried, and screened to give product with average particle size 2.8-4.8 mcm, relative x-ray luminescence 101-131%, and relative afterglow 10-85%. EFFECT: improved luminophor characteristics. 1 tbl, 2 ex