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- F. Ames, R.A. Baartman, P.G. Bricault, K. Jayamanna, A. Mjøs
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
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After initial commissioning of the charge state breeder for radioactive ions at the TRIUMF/ISAC facility further tests on the performance of the system have been performed. One of the major problems found was the high background of stable ions from the ECR source, mainly C, N, O, Ar, Fe, Ni, C and Cr. The main source of those is the residual gas and sputtered material from the plasma chamber wall and from the surrounding electrodes. Although their intensity is small it can be orders of magnitude more than the intensity from the radioactive ions. Therefore, the original stainless steel plasma chamber of the Pantechnik PHOENIX ECR source has been exchanged to aluminium with an ultra pure aluminium coating, all electrodes for injection and extraction of the ions have been replaced with aluminium and the iron joke at the extraction side, which is part of the vacuum system in the PHOENIX source has been coated as well. This combined effect has reduced the amount of background ions substantially. Detailed results on the performance of the source after those changes will be presented.
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