X-RAY INTENSIFYING SCREEN

• Main Authors: YOKOTA, KAZUTO, SAITO, AKIHISA
• Format: Patent
• Language: English
• Published: 23.05.1990
• Subjects: ADHESIVES; AUXILIARY PROCESSES IN PHOTOGRAPHY; CHEMISTRY; CINEMATOGRAPHY; DYES; ELECTROGRAPHY; GAMMA RAY OR X-RAY MICROSCOPES; HOLOGRAPHY; IMPREGNATING OR COATING OF PAPER; IRRADIATION DEVICES; MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FORELSEWHERE; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; NUCLEAR ENGINEERING; NUCLEAR PHYSICS; PAINTS; PAPER NOT OTHERWISE PROVIDED FOR; PAPER-MAKING; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR,STEREO-PHOTOGRAPHIC PROCESSES; PHOTOGRAPHY; PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHYSICS; POLISHES; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; PRODUCTION OF CELLULOSE; PULP COMPOSITIONS; TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOTOTHERWISE PROVIDED FOR; TEXTILES; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G

This invention concerns an intensifying screen using a phosphor capable of emitting light under X-ray excitation. This intensifying screen is characterized by the fact that the phosphor layer in the intensifying screen comprises a first phosphor layer containing a phosphor represented by the general formula (I): MaLn1-x-(2/3)aDO4:XR <+> (I) (wherein M stands for at least one divalent metal element selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn, and Cd, Ln for at least one element selected from the group consisting of Y, Gd, La, and Lu, D for either or both of Ta and Nb, R for at least one member selected from the group consisting of Tm, Pr, Sm, Eu, Tb, Dy, Yb, and self-activators, a for a value satisfying the expression, 0 < a </= 1, and x for a value satisfying the expression, 0 </= x </= 0.05) and formed on the aforementioned substrate side and a second phosphor layer containing CaWO4 and formed on the aforementioned protective layer side. Owing to this characteristic feature, the intensifying screen enjoys improved granularity without any sacrifice of sensitivity or sharpness.