| 摘要 |
PCT No. PCT/FI83/00059 Sec. 371 Date Apr. 18, 1984 Sec. 102(e) Date Apr. 18, 1984 PCT Filed Aug. 19, 1983 PCT Pub. No. WO84/00848 PCT Pub. Date Mar. 1, 1984.A method and a device for operating and focusing a tomographic x-ray unit using an electron beam and embodying at least one electron gun (1), an anode (2) at which the gun is aimed as well as the x-ray detectors (5) needed to produce a tomographic photograph. In order to construct a device with a sufficiently short exposure time and capable of taking tomographic photographs of fast-moving objects, it is particularly characteristic of this invention that an electron beam (8) emitted by an electron gun (1) is roughly deflected at a hole (4) in the focusing plane (3) which, by means of focusing field lines, draws the electrons into the hole, focuses and accelerates the electron beam which strikes the surface of the anode (2), generating an x-ray source, and that the focusing hole (4) is moved in regard to the anode (2) to generate a series of x-ray sources needed to produce a "layerwise" tomographic photograph of the object under examination.
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