| 摘要 |
PROBLEM TO BE SOLVED: To correct the movement of a focus position and a focal dimension by optimizing a deflecting magnetic field to deflect the electron beam of an X-ray tube device. SOLUTION: An electromagnet 40 serving as a deflecting magnetic field generating means is disposed in close vicinity to the envelope 16 of an X-ray tube 10. The electromagnet 40 has a U-shaped iron core 40 and a winding 44, the end faces 42a, 42b of the rod of the iron core 42 are processed to inclined surfaces, and the deflecting magnetic field is formed in a gap 46 between the end faces 42a, 42b. The inclined surfaces of the end faces 42a, 42b are processed so that the distance of the gap 46 becomes larger as they part from a tube axis 48 in the main radiating direction 35 of X-rays. Therefore, when the magnet 40 is excited, the magnetic field intensity of the deflecting magnetic field becomes high in a place close to the tube axis 48, and becomes low in a remote place. When deflecting the electron beam by this deflecting magnetic field, a large focal length dimension can be obtained in comparison with a conventional magnetic field having uniform intensity. COPYRIGHT: (C)2008,JPO&INPIT
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