Radiation image pickup tube

Claim 1

A DIRECT VIEW STORAGE TUBE COMPRISING AN INPUT SCREEN OF PHOTOEMISSIVE MATERIAL WHICH EMITS AN ELECTRON BEAM IN RESPONSE TO A RADIATION IMAGE DIRECTED THEREON, AN OUTPUT SCREEN SPACED FROM SAID INPUT SCREEN AND HAVING A LAYER OF PHOSPHOR MATERIAL THEREON CAPABLE OF EMISSION OF LIGHT IN RESPONSE TO ELECTRON BOMBARDMENT, A STORAGE ELECTRODE POSITIONED BETWEEN SAID INPUT SCREEN AND SAID OUTPUT SCREEN, SAID STORAGE ELECTRODE COMPRISING A CONTINUOUS LAYER OF ELECTRICALLY CONDUCTIVE MATERIAL, AND A CONTINUOUS LAYER OF SECONDARY EMISSIVE MATERIAL POSITIONED ON THE SURFACE OF SAID CONDUCTIVE LAYER FACING SAID OUTPUT SCREEN, MEANS FOR DIRECTING A RADIATION IMAGE TO BE STORED ONTO SAID INPUT SCREEN TO GENERATE AN ELECTRON IMAGE CORRESPONDING TO SAID RADIATION IMAGE, MEANS FOR ACCELERATING SAID ELECTRON IMAGE TO BOMBARD SAID STORAGE ELECTRODE AND PENETRATE SAID CONDUCTIVE ELECTRODE AND ENTER SAID SECONDARY EMISSIVE LAYER, SAID SECONDARY EMISSIVE LAYER EXHIBITING THE PROPERTY OF EMITTING ELECTRONS FROM THE EXPOSED SURFACE AT A RATIO GREATER THAN ONE AND THE RATE OF YIELD OF SAID ELECTRONS INCREASING WITH TIME AT A CONSTANT PRIMARY BOMBARDMENT, MEANS FOR MAINTAINING THE STORED RADIATION PATTERN FROM SAID INPUT SCREEN FOR A SUBSTANTIAL LENGTH OF TIME TO PRODUCE A CHARGE IMAGE ON THE EXPOSED SURFACE OF SAID SECONDARY ELECTRON EMISSIVE LAYER OF ENHANCED CONTRAST OVER SAID INPUT RADIATION IMAGE, AND MEANS FOR DIRECTING AN ELECTRON BEAM OF UNIFORM INTENSITY OVER THE EXPOSED SURFACE OF SAID CONDUCTIVE LAYER TO GENERATE SECONDARY ELECTRONS FROM THE EXPOSED SURFACE OF SAID SECONDARY ELECTRON EMISSIVE LAYER CORRESPONDING TO SAID CHARGE IMAGE AND MEANS FOR ACCELERATING SAID SECONDARY ELECTRONS TO BOMBARD SAID OUTPUT SCREEN TO PROVIDE AN INTENSIFIED IMAGE OF ENHANCED CONTRAST.