高性能全永磁ECR离子源LAPECR2的研制

研制了一台体积和重量都较大、设计性能较高的全永磁电子回旋共振(Electron cyclotron resonance,ECR)离子源LAPECR2(Lanzhou all permanent magnetic ECRion source No.2 ).该离子源将用于中国科学院近代物理研究所320 kV高压平台,为其提供强流高电荷态离子束流.LAPECR2的研制采用全新的全永磁磁体结构设计,通过采用高性能的NdFeB永磁材料、优化的磁结构设计以及精确的计算,实测源体的磁场参数能达到高性能ECR离子源的设计要求.离子源采用较高频率的14.5 GHz微波馈入加热等离子体,波导直接馈入离子源以增强馈入微波的稳定性与效率.此外,还大量采用了一些有利于提高离子源高电荷态离子产额的关键技术,如铝内衬等离子体弧腔、负偏压盘、铝制等离子体电极、三电极引出系统、辅助掺气等.

Development of a high performance all-permanent magnetic ECR ion source

An all-permanent magnetic electron cyclotron resonance (ECR) ion source LAPECR2 (Lanzhou all-permanent ECR ion source No.2) is being developed in Lanzhou. This ion source is believed to be a larger and heavier all-permanent magnetic ECR ion source in the world, which provides very high magnetic field inside the working volumn. This ion source will work on the IMP (Institute of Modern Physics) 320kV high voltage platform and provide intense high charge state ion beams for the successive experimental terminals. Many innovative methods have been adopted in the magnet design of LAPECR2. Due to the adoption of high remanence NdFeB material, optimum design and accurate calculation, the measured magnetic parameters are well up to the requirements of a high performance 14.5GHz ECR ion source. An off-axis rectangular wave-guide is used to feed 14.5GHz microwave inside the plasma chamber to heat the plasma. The adoption of off-axis RF feeding method will make the plasma more stable and the RF power feeding more efficient. Additionally, many tricky techniques such as the aluminum liner inside the plasma chamber, the biased-disc, the aluminum plasma electrode, the triode extraction system, the addition of auxiliary gas, etc, are employed to increase the production efficiency of high charge state ions.