LARGE APERTURE ION SOURCE

摘要

PURPOSE:To make a large aperture insulating spacer needless by mounting an ion beam drawing-out electrode system on a flange for fixing an electrode between an insulating flange and a fixing flange in order to maintain an electrode interval at fixed value with an insulating spacer while making the insulating flange inner diameter and an electrode on the arc chamber side larger than the arc chamber opening. CONSTITUTION:An ion beam drawing-out electrode system 42 having a plasma electrode 20 opposing to an arc chamber 10 is fixed to a flange 34 provided between a fixing flange 60, which fixes the arc chamber to a vacuum container 62 and an insulating flange 32 while maintaining the suppresser electrode 28 and the drawing-out electrode 30 having many opening holes of the beam drawing-out electrode system 42 with the pillar-shaped insulating spacers 66 and 68 at fixed value and the inner diameter of the insulating flange 32 is made to be larger than the inner diameter of the arc chamber 10 while making the plasma electrode 20 opposing to the ark chamber larger than the inner diameter of the arc chamber. According to said constitution, an insulating spacer having a large aperture is not required thus reducing plasma leakage from the arc chamber.