Kubo Wataru, Hamada Kouta, Onishi Koji, Takeda Tatsuto, Okumura Kazuki, Omori Takayuki, Ishihara Masaki, Harisaki Shuhei, Kato Yushi
Division of Electronical, Electronic and Information Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita-shi, Osaka 565-0871, Japan.
Rev Sci Instrum. 2020 Feb 1;91(2):023317. doi: 10.1063/1.5128576.
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.
大阪大学对如何在电子回旋共振离子源（ECRIS）上高效产生多电荷离子进行了研究。值得注意的是，近年来，我们专注于通过新的共振叠加到电子回旋共振（ECR）等离子体来进行加热。为了评估其效率，我们需要知道仅使用ECR加热的最大效率，然后，需要对ECR加热进行进一步优化。考虑到波的传播，我们沿着真空室的几何轴在磁镜端安装了同轴半偶极天线。我们旨在激发右旋极化（RHP）波的强度以实现高效的ECR，因为RHP波会引发ECR。我们通过朗缪尔探针测量等离子体参数以及提取离子束的电荷态分布（CSD），并研究它们对入射微波功率和压力的定性趋势。我们比较了在通过同轴半偶极天线和棒状天线的微波馈送系统情况下，离子束及其CSD在微波功率方面的定性趋势。明确了改进前和升级后的微波馈送系统之间的差异。
