| 摘要 |
PROBLEM TO BE SOLVED: To provide a certain distribution of doses to the surface of a subject to be irradiated, when the surface of a three-dimensional object is irradiated with electron rays, by making it possible to emit electron rays to toward the subject from the overall circumference of the subject, with a certain distribution of strengths, without rotating the subject. SOLUTION: Electrons emitted from cathodes 2-1 and 2-2 provided within a vacuum container 100 are accelerated between the cathodes and an anode 3 having electron holes 5-1 and 5-2 therein, and the cathodes and the anode are configured to be capable of circling within a vacuum region. A structure 4-4 including an electron transmission window for taking electrons out of the vacuum container is formed in a cylindrical shape and provided with alternate first thick portions and second thin portions along the circumferential direction. The second portions work to allow transmission of electrons therethrough while forming a vacuum bulkhead, and the first portions work to cool the second portions while maintaining mechanical strength. |
