RFQ冷却聚束器的离子引出系统

Extraction System for RFQ Cooler and Buncher

论述了RFQ冷却聚束器的两种离子引出系统——静电引出和小型RFQ方法的模拟结果,并通过流体力学方法计算了设计中的静电引出系统的氦气流量和系统可能获得的真空度.研究结果表明在较低氦气气压时,应该选用小型RFQ引出方法,以获得更好的束流品质,而在较高氦气气压时,只能选用静电引出方法.另外,由于设计中的RFQ冷却聚束器经常工作于高氦气气压条件下,因此高纯度氦气的回收和再利用是必需的.

Two different systems, static electric guide and miniature RFQ （Radiofrequency Quadrupole）, for ion extraction from a RFQ cooler and buncber have been discussed. By fluid dynamics calculation, the mass flow rate and possibly available vacuum of the being designed static electric extraction system have also been evaluated. We have made conclusions that the miniature RFQ should be used for a low helium buffer gas pressure to obtain a good beam quality, but for a higher gas pressure the static electric guide must be used. In addition, because the being designed RFQ cooler and buncber will always work in a relatively high gas pressure, the recycling and reusing of the high purity helium gas must be considered.