Operational Performance of the LBL 88-Inch Cyclotron with an ECR (Electron Cyclotron Resonance) Source

摘要

The 88-Inch Cyclotron began regular operation with the ECR (Electron Cyclotron Resonance) source in January 1985. Since then about 80% of the cyclotron operating schedule has been with the ECR source. The light-ion filament source is used only for runs two or more shifts in length using proton, deuteron, sup 3 He, or alpha beams. Occasionally the polarized ion source is used. The heavy-ion PIG sources are no longer used. The operating experience with the Cyclotron + ECR has been highly successful in terms of reliability, stability, production of high charge state currents, and range of ions which can be produced. The performance of the Cyclotron + ECR has steadily improved since regular operation began. The improvement is a result of better source performance, better stability and tuning of the injection line, and better cyclotron tuning. Development of the ECR source has resulted in improved high charge state performance and a greater variety of ion species. The LBL ECR now produces 14 mu A of O sup 7+ , 1 mu A of O sup 8+ , 72 mu A of Ar sup 9+ , 1.4 mu A of Ar sup 14+ , 5 mu A of I sup 25+ , and .009 mu A of I sup 30+ . Metal ions from Mg, K, and Ca are produced in the ECR using an oven to inject vapor into the plasma chamber. Operation with the oven is quite stable and frequently requires no adjustment during runs lasting several days. Beams of F, Si, S, and Ti have been produced using various compounds as gases or solids with the oven. The overall transmission from source analyzing magnet to cyclotron external beam is typically 2 to 10% with a maximum of 17%. As a result of the improved source performance and transmission a wide variety of new beams can be produced. For example, a 32.5 MeV/u sup 16 O sup 8+ beam and sup 48 Ca sup 11+ beams with energy from 200 to 350 MeV have been used for nuclear physics experiments. A 1.08 GeV sup 36 Ar sup 18+ beam was used to test the response of various scintillator materials to intermediate energy heavy ions. (ERA citation 12:027242)