HIGH-BRIGHTNESS PROTON-BEAMS AT THE NAC NUCLEAR MICROPROBE BY ACCELERATION OF H-2 IONS

The advantage of using the H-2 part of the beam for the acceleration o f hydrogen ions is demonstrated. An order of magnitude improvement in beam brightness is measured for two ion sources: a duoplasmatron and a Penning source. The high-momentum beams require the microbeam lenses to be used with high focussing power. Therefore, the performance of th e microprobe lenses when operating at their maximum strength has been investigated. The spatial resolution in the microprobe improved signif icantly when using the high-intensity H-2 beam; the current limitation being the beam stability.