Abstract: An X-ray detector tube comprising an essentially rectangular, elongate housing (1) having a forward wall, a rear wall and sidewalls, which tube has an elongate proximity focus image intensifier mounted therein and which housing has a vacuum established therein, in which the rear wall (5) of the tube exhibits a considerably higher resistance to deformation than the sidewalls.

Abstract: An image intensifier of the proximity-focus type, comprising at least one photocathode and at least one anode screen located opposite to the photocathode, said photocathode and said anode screen being disposed in a hollow body in which a vacuum prevails, while, in use, there is an electrical field between cathode and anode. According to the invention the photocathode surface and the anode screen surface extend substantially parallel to the axis of the hollow body.

Abstract: A method of making the cathode of a diode image intensifier tube by evaporating some alkali metals and antimony on to the inner surface of a cathode window which by means of a layer of frit is joined to a metallic cathode flange, and in which there is provided between the cathode and the cathode flange, or, as the case may be, the cathode housing, an electrical resistance of a pre-determined value such that at light levels at which there is a danger of the anode being burnt, the diode image intensifier tube is defocussed or cut off, and wherein prior to the evaporation of the metals an alkali-resistant and insulating layer is applied to the frit layer, and that the evaporation of the antimony is carried out so that there is formed between the cathode and the cathode flange an area extending around the cathode and where no antimony is present, and that at least one galvanic connection is passed vacuum-tight outside the diode image intensifier tube, and one end of said connection is arranged at the place of the

Abstract: An image intensifier tube has a light-absorbing electron-permeable layer covering an aluminum film overlying a layer of luminescent material in the anode structure of the tube. The light absorbing layer is silicon or boron, or a compound of silicon or boron, and has a thickness of about one-fourth the average wave length of light which impinges upon the photocathode during operation of the image intensifier tube.

Abstract: A method of making the cathode of a diode image intensifier tube by evaporating some alkali metals and antimony on to the inner surface of a cathode window which by means of a layer of frit is joined to a metallic cathode flange, and in which there is provided between the cathode and the cathode flange, or, as the case may be, the cathode housing, an electrical resistance of a pre-determined value such that at light levels at which there is a danger of the anode being burnt, the diode image intensifier tube is defocussed or cut off, and wherein prior to the evaporation of the metals an alkali-resistant and insulating layer is applied to the frit layer, and that the evaporation of the antimony is carried out so that there is formed between the cathode and the cathode flange an area extending around the cathode and where no antimony is present, and that at least one galvanic connection is passed vacuum-tight outside the diode image intensifier tube, and one end of said connection is arranged at the place of the

Abstract: A process for applying within an image intensifier tube, in particular one of the proximity-focus type, a light absorbing, electron permeable layer on to a film coated on a layer of luminescent material applied to the anode of the tube. The layer is applied by evaporation of a low atomic weight element, preferably silicon or boron, or a compound of such an element, under conditions of high vacuum, preferably in the range of 10.sup.-5 to 10.sup.-6 torr, and up to a thickness of 1/4.lambda., where .lambda. is the average wavelength of the light which during operation of the tube impinges upon the photocathode thereof.

Abstract: An image intensifier tube is made by building an anode window subassembly and a cathode window subassembly each ending in a ring having a projecting peripheral edge. The two subassemblies are placed in a vacuum chamber and the two rings are peripherally interconnected by cold welding.