| 摘要 |
PURPOSE:To obtain an ion beam having a big aperture and high density by a method wherein a moving distance of an electron making cycloidal movement is lengthened, and the probability of colliding with neutral gas prticles and metal particles is hightened in order to generate ions with high density. CONSTITUTION:Plate-shaped anode 2 made of a non-magnetic substance is maintained by an insulator 3 in about the center inside of an outer cylinder 1 of an ion source while cathode of pure iron is provided below anode in parallel with said anode. Said cathode is composed of two upper- and -lower plate bodies 4b and 4c through an axislike connector 4a just like a reel while the respective plate bodies form a magnetic circuit en bloc and almost ringlike gaps 5a, 5b, 6a and 6b are provided in about the middle part of the center and the end while between the respective ends of the upper plate body 4b and the lower plate body 4c, a ringlike permanent magnet 7 or an electromagnet of which the side connecting with the upper plate is the N(S) pole and the side connecting with the lower plate body is S(N) pole, is held between. Further, the peripheral ringlike regions 8 and 9 of the gaps 5a and 5b of the upper plate body 4b of said cathode are composed of a metal material to become the required ion source. |
