A negative ion source (10) is constructed to produce H<-> ions without using Cesium. A high percentage of secondary electrons (23) that typically accompany the extracted H<-> are trapped and eliminated from the beam by permanent magnets (14) in the initial stage of acceleration. Penetration of the magnetic field from the permanent magnets (14) into the ion source (10) is minimized. This reduces the destructive effect the magnetic field could have on negative ion production and extraction from the source. A beam expansion section (19) in the extractor results in a strongly converged final beam.
