How to produce multicharged ions efficiently on an electron cyclotron resonance ion source (ECRIS) has been investigated at Osaka University. Notably, in recent years, we have focused on heating by new resonance superimposing to electron cyclotron resonance (ECR) plasma. To evaluate its efficiency, we need to know the maximum efficiency of heating with ECR alone, and then, further optimization of ECR heating is required. In consideration of wave propagation, we installed the coaxial semi-dipole antenna on the mirror end along the geometrical axis of the vacuum chamber. We aim at exciting the strength of right-hand polarization (RHP) waves for efficient ECR because RHP waves give rise to ECR. We measure plasma parameters by Langmuir probes and charge state distributions (CSDs) of the extracted ion beams and investigate their qualitative tendencies to incident microwave powers and pressures. We compare the qualitative trend of ion beams and their CSD on microwave power in the case of both the microwave feeding system by the coaxial semi-dipole antenna and that by the rod antenna. Differences between the microwave feeding system before improving and then after upgrading are made clear.

中文翻译：

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电子回旋共振多电荷离子源的同轴半偶极天线微波馈电

大阪大学研究了如何在电子回旋共振离子源 (ECRIS) 上有效地产生多电荷离子。值得注意的是，近年来，我们专注于通过叠加在电子回旋共振 (ECR) 等离子体上的新共振来加热。为了评估其效率，我们需要知道单独使用 ECR 加热的最大效率，然后需要进一步优化 ECR 加热。考虑到波的传播，我们沿真空室的几何轴在镜端安装了同轴半偶极天线。我们的目标是激发右极化 (RHP) 波的强度以实现有效的 ECR，因为 RHP 波会引起 ECR。我们通过朗缪尔探针和提取离子束的电荷态分布 (CSD) 测量等离子体参数，并研究它们对入射微波功率和压力的定性趋势。我们比较了同轴半偶极天线和棒状天线微波馈电系统中离子束及其CSD对微波功率的定性趋势。明确了改进前和升级后微波馈电系统的区别。