Addressing contamination in ECR charge breeders

The Electron Cyclotron Resonance (ECR) ion source was first utilized for charge breeding in 1995 [1]. Since that time the charge breeding technique has been refined. Single charge state efficiency has improved by a factor of ten, the efficiency discrepancy between solid and gaseous species has narrowed, and low-mass species efficiency has improved. But the limiting characteristic of the ECR charge breeder continues to be a high level of contamination which often obscures the beam of interest [2]. Multiple techniques have been employed to reduce this contamination with varying levels of success, and attempts are currently underway to improve upon the successes achieved to date. This paper will review those past techniques, current attempts, and possible future paths for reducing the contamination level in ECR charge breeders.