Binderless storage phosphor screen with needle shaped crystals

Abstract

A binderless storage phosphor screen with needle shaped crystals, wherein the phosphor is an alkalihalide phosphor and the needles show high [100] unit cell orientation in the plane of the screen.

1 . A binderless storage phosphor screen comprising an alkali metal storage phosphor characterised in that said screen shows an XRD-spectrum with a (100) diffraction line having an intensity I 100  and a (110) diffraction line having an intensity I 110 , so that I 100 /I 110 ≧1, when said XRD-spectrum is measured according to TEST A.  
     
     
         2 . A binderless storage phosphor screen according to    claim 1   , wherein I 100 /I 110 ≧5.  
     
     
         3 . A binderless storage phosphor screen according to    claim 1   , wherein said phosphor is an alkali metal phosphor.  
     
     
         4 . A binderless storage phosphor screen according to    claim 1   , wherein said phosphor is a CsX:Eu stimulable phosphor, wherein X represents a halide selected from the group consisting of Br and Cl is used, prepared by a method comprising the steps of 
 mixing said CsX with between 10 −3  and 5 mol % of an Europium compound selected from the group consisting of EuX′ 2 , EuX′ 3  and EuOX′, X′ being a member selected from the group consisting of F, Cl, Br and I,    firing said mixture at a temperature above 450° C.    cooling said mixture and    recovering the CsX:Eu phosphor.    
     
     
         5 . A binderless storage phosphor screen according to    claim 1   , containing a CsX:Eu stimulable phosphor, wherein X represents a halide selected from the group consisting of Br and Cl wherein said screen is prepared by a method comprising the steps of: 
 mixing said CsX with between 10 −3  and 5 mol % of an Europium compound selected from the group consisting of EuX′ 2 , EuX′ 3  and EuOX′, X′ being a halide selected from the group consisting of F, Cl, Br and I    bringing said mixture in condition for vapour deposition and    depositing said mixture on a substrate by a method selected from the group consisting of physical vapour deposition, thermal vapour deposition,, chemical vapour deposition, electron beam deposition, radio frequency deposition and pulsed laser deposition.    
     
     
         6 . A binderless storage phosphor screen according to    claim 2    wherein said phosphor is an alkali metal phosphor.  
     
     
         7 . A binderless storage phosphor screen according to    claim 2   , wherein said phosphor is a CsX:Eu stimulable phosphor, wherein X represents a halide selected from the group consisting of Br and Cl is used, prepared by a method comprising the steps of: 
 mixing said CsX with between 10 −3  and 5 mol % of an Europium compound selected from the group consisting of EuX′ 2 , EuX′ 3  and EuOX′, X′ being a member selected from the group consisting of F, Cl, Br and I,    firing said mixture at a temperature above 450° C.    cooling said mixture and    recovering the CsX:Eu phosphor.    
     
     
         8 . A binderless storage phosphor screen according to    claim 2   , containing a CsX:Eu stimulable phosphor, wherein X represents a halide selected from the group consisting of Br and Cl wherein said screen is prepared by a method comprising the steps of : 
 mixing said CsX with between 10 −3  and 5 mol % of an Europium compound selected from the group consisting of EuX′ 2 , EuX′ 3  and EuOX′, X′ being a halide selected from the group consisting of F, Cl, Br and I    bringing said mixture in condition for vapour deposition and    depositing said mixture on a substrate by a method selected from the group consisting of physical vapour deposition, thermal vapour deposition,, chemical vapour deposition, electron beam deposition, radio frequency deposition and pulsed laser deposition.    
     
     
         9 . Method for producing a binderless storage phosphor screen comprising the steps of: 
 providing an alkali metal storage phosphor    vacuum depositing said phosphor on a substrate characterised in that during said step of vacuum depositing said substrate is kept at a temperature T, such that 50° C.≦T≦300° C. and said vacuum deposition proceeds ion an Ar-atmosphere with an Ar-pressure of at most 3 Pa.    
     
     
         10 . A method according to    claim 9   , wherein said temperature of said substrate T, is such that 90° C.≦T≦200° C.  
     
     
         11 . A method according to    claim 9   , wherein said Ar-pressure is kept between 0.20 and 2.00 Pa, both limits included and said temperature of said substrate is adjusted so as to have a product between temperature, in degree Celsius, and Ar-pressure, in Pa, between 20 and 350, both limits included.  
     
     
         12 . A method according to    claim 9   , wherein during said step of vacuum deposition a deposition rate of at least 1 mg/cm 2 min is used.  
     
     
         13 . Method for producing a binderless storage phosphor screen comprising the steps of: 
 combining phosphor precursors for an alkali metal storage phosphor    vacuum depositing said combination of phosphor precursors on a substrate characterised in that during said step of vacuum depositing said substrate is kept at a temperature T, such that 50° C.≦T≦300° C. and said vacuum deposition proceeds ion an Ar-atmosphere with an Ar-pressure of at most 3 Pa.    
     
     
         14 . A method according to    claim 13   , wherein said temperature of said substrate T, is such that 90° C.≦T≦200° C.  
     
     
         15 . A method according to    claim 13   , wherein said Ar-pressure is kept between 0.20 and 2.00 Pa, both limits included and said temperature of said substrate is adjusted so as to have a product between temperature, in degree Celsius, and Ar-pressure, in Pa, between 20 and 350, both limits included.  
     
     
         16 . A method according to    claim 13   , wherein during said step of vacuum deposition a deposition rate of at least 1 mg/cm 2 min is used.