| 摘要 |
It is described an X-ray tube (100) comprising a rotating anode (130), which is provided with a pull electrode (140). The pull electrode (140) interacts with a fixed electron source (110) in order to generate a modulated electron beam (120a, 120b). The beam modulation may be an intensity variation and/or a spatial deflection. The pull electrode (140) is mounted in a fixed position with respect to the anode (130) and rotates together therewith. The pull electrode (140) may have a hole (141) for passing the electron beam (120a). When being in front of the electron source (110), the pull electrode (140) causes a high electric field (142a) such that a strong electron beam (120a) is generated. When being not in front of the electron source (110) only a low current or a zero current electron beam (120b) is generated. However, the pull electrode (740) may also cause a radial beam deflection such that depending on the angular position of the anode (730) the position of a focal spot (721a, 721b) of the electron beam (720) is varied.
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