Abstract: The cathode holder 4 has two terminals 8, 9 which are rigidly connected to one another and together form a flange 20 which by means of a pressure bearing with spheres 27, 28 made of a ceramic material is supported in a carrier flange 3 connected to the control electrode 5. The spheres 27, 28 rest in rolling paths aligned in radial direction to the optical axis 14 and provide a centering of the cathode 7 with respect to the control electrode 6 which is independent of expansions.

Abstract: An electron beam gun comprising a beam generator (4), an acceleration chamber (7) and a beam-guide chamber (10). The beam-guide chamber is formed by a jacket tube (19) and a beam-guide tube (18), which extends to the work chamber (1) and is surrounded by a focusing lens (15) and a deflecting device (17). For the purpose of readily adapting the equipment to suit various objective distances and for making cleaning and inspection easier, the jacket tube (19) takes the form of a hollow cylinder and is secured between two connecting flanges (20, 21) in a manner whereby it can be replaced. The upper connecting flange (20) carries a centering flange (28), on which the beam-guide tube is suspended, a shut-off valve (11) being optionally provided between the centering flange and the beam-guide tube. The lower connecting flange (21) surrounds a vacuum-connecting flange (34) in which is fitted the lower end of the beam-guide tube (18).

Abstract: An electron gun with a beam generator 4, a high-voltage connection 25 and a high-voltage insulator 23 is equipped with at least one insulating transformer 26, 27 and circuit elements 43 for producing auxiliary voltages at high-voltage potential. The beam generator 4 and the high-voltage insulator 23. are surrounded by a grounded metallic jacket 32. The insulating transformer is arranged above the high-voltage insulator 23. For the purpose of solving the problem of permitting use of a single-pole high-voltage cable, the one or more insulating transformers 26, 27 are embedded in an insulating member 24 which is mounted directly on the high-voltage insulator 23. The portion of the insulating member 24 that projects beyond the grounded jacket 32 is surrounded by a metallic hood which, together with the jacket 32, forms a common Faraday cage. The circuit elements 43 for the auxiliary voltages are likewise arranged in the Faraday cage.