| 摘要 |
In an X-ray tube having an anode supported for rotation and an annular target track mounted upon the anode, a cathode spaced apart from the anode projects a beam of electrons onto the target track within a focal spot. The cathode is designed to normalize the impact temperature across the focal spot, as a function of length. In accordance therewith, the cathode comprises a filament and a cathode cup, wherein the filament is disposed to project the electron beam onto the target track to generate X-rays, when a high voltage potential difference is established between the filament and the anode. The filament and the cathode cup are respectively configured to selectively form the electron beam so that the beam provides an electron distribution within the focal point which maintains each point within the focal spot at substantially the same temperature.
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