Low Z gas mixing effects of Ar and Xe multicharged ions in electron cyclotron resonance ion source

An electron cyclotron resonance (ECR) ion source (ECRIS) has wide applications such as cancer therapy and material synthesis. We have constructed a single ECRIS capable of producing various ions with low to high mass/charge ratio, and have been conducting various experiments. We focus on the efficient production of multicharged ions and aim to increase the yield of multicharged ions by new effects of electromagnetic waves in ECRIS. We investigated the possibility of selective heating to low Z ions under low Z gas mixing. Therefore, as a preliminary step of these experiments, the low Z gas mixing effect with rare gases are investigated. The optimum mixing ratio of the main gas Ar and the low Z gas He was investigated by varying the mixing ratio. The Ar multicharged ion beam current, impurity fraction and plasma parameters were measured. As a result, it was confirmed that the Ar multicharged ion yield was sufficient reproducibly increased by mixing He gas into Ar plasma. In addition, this from the measured plasma parameters is not an effect of the plasma parameters, but maybe a cooling effect.