Progress in submicron width ion beam system using double acceleration lenses

Ishii, Yasuyuki; Isoya, Akira*; Kojima, Takuji

The conception for this microbeam formation, which consists in combining beam contraction effect of acceleration process with the lens action, was published in 1991. The test machine was installed in JAERI. The study of reducing beam size showed that the incident beam condition strongly depend on its size. Recently about 40 keV stable microbeam of 0.1 m order in radius has been obtained after optimizing the ion beam injection system. The test machine is composed of a duoplasmatron-type discharge source, an initial acceleration system, a main acceleration lens system, and microbeam diameter measurement system. We will present the schematic of the test machine and the result of the beam size measurement. Performance of the system will also show to depend mostly on how nicely a low energy injection beam is prepared at the entrance region.