Initial performance of a 6 GHz "volume" ECR ion source

An all-permanent-magnet, 6-GHz "volume-type" ECR ion source has been constructed and evaluated. This source employs a novel magnetic field configuration with an extended central flat region to form a large, on-axis, ECR volume. It can also be converted to a traditional minimum-5 source where the ECR zones are surfaces. Comparisons are made of the performance of the source when operated in both "volume" and "surface" modes. According to the preliminary results, the "volume" mode is superior in terms of ion beam intensities and charge-state distributions.