Abstract: An X-ray imaging tube comprising an vacuum envelope, and input screen located in the input end of the envelope, an output screen located in the output end of the envelope, an anode located in the output end of the envelope, and a plurality of beam-converging electrodes located in the envelope and arranged along the inner surface of the envelope. The tube has an magnification of used input field size of 2.3 or more. The components of the tube have such positions and sizes, thus satisfying the following relations:3.5.ltoreq.G3.sub.D /A.sub.D .ltoreq.5.0-3.65.times.MAG+1.00.ltoreq.G3.sub.L /L.ltoreq.-3.65.times.MAG+1.05where L is the distance between the input and output screens, A.sub.D is the inside diameter of the anode or one of the beam-converging electrodes set at the same potential as the anode, which is closer to the input screen than any other beam-converging electrodes set at the same potential as the anode, G3.sub.

Abstract: An output phosphor film used in an output screen of an image intensifier is made of ZnS or (Zn, Cd)S host material and at least one activator element selected from the group consisting of Cu, Ag, Au, Al, and Cl. The phosphor film is formed on a face plate by means of chemical vapor-deposition, or physical vapor deposition in an inert-gas atmosphere having a pressure of 1 Pa or more, and is heat-treated. The formed phosphor film has hexagonal (Wurtzite-type) crystal and/or cubic (sphalerite-type) crystal structure. These crystals are orientated such that the (002) planes of the hexagonal crystals and/or the (111) planes of the cubic crystals are substantially parallel to the face plate.

Abstract: A semiconductor pressure converter includes a silicon pressure sensing element, a silicon base hermetically attached to the sensing element to bear the element and a metal pipe connected to the silicon base so as to introduce a pressure to the sensing element through the silicon base.