21 mA强流多峰场负氢离子源的设计与实验研究  

Design and Experiment Study of 21 mA H - Multi-cusp Ion Source

作　　者：农竹杰 贾先禄[1] 张贺 郑侠[1] 丁傲轩 吴聪 凌丽 贾心琦 马楚韵 颜利华 方明阳 NONG Zhujie;JIA Xianlu;ZHANG He;ZHENG Xia;DING Aoxuan;WU Cong;LING Li;JIA Xinqi;MA Chuyun;YAN Lihua;FANG Mingyang(China Institute of Atomic Energy,Beijing 102413,China)

机构地区：[1]中国原子能科学研究院,北京102413

出　　处：《原子能科学技术》2024年第5期1137-1144,共8页Atomic Energy Science and Technology

摘　　要：负氢离子源是强流质子回旋加速器的核心设备之一,其性能指标很大程度上决定了加速器最终束流的流强与品质。本文介绍了一种运用于强流质子回旋加速器上的多峰场负氢离子源的设计与实验研究,针对强流质子回旋加速器的高流强需求,通过深入研究高密度等离子体的产生和约束、高效虚拟过滤场、强流负氢离子引出等关键问题,解决制约提高负氢束流强度的瓶颈,在中国原子能科学研究院原有15 mA多峰场负氢离子源的基础上,基本保留原有的多峰场设计,通过采用四圆环灯丝结构,优化虚拟过滤场和引出结构,并改善真空系统,将平均引出束流提高至21 mA,实现了我国加速器领域灯丝驱动直流负氢离子源20 mA流强的突破。The ion source is one of the key devices for the high-intensity cyclotron,which exerts influence on the beam intensity and applications of the machine.As part of the cyclotron research and development effort,China Institute of Atomic Energy(CIAE)has been developing arc discharge H-ion sources based on volume production and multi-cusp magnetic configuration since 1997.In 2000,5.2 mA H-beam was reached and 15 mA H-beam was achieved in 2010.After a long break,H-ion source development started again in 2022 in order to improve performance of the main H-ion source of the CIAE 18 MeV cyclotron and to fulfill the requirement of future other high intensity proton beam cyclotrons for the high intensity H-ion.A new H-ion source and test stand was built at CIAE in 2023.The design of this new ion source was based on the experience on our previous 15-20 mA H-ion source and the source at TRIUMF.Major efforts included the study of the virtual filter magnetic field for filtering out fast electrons,multi-cusp confining magnetic field,four-half-circle ring filaments length and location,improvement of extraction structure and upgrading of vacuum system and power supplies.Up to now,more than 21 mA of H-beam were obtained at a high voltage of 35 kV from a plasma electrode hole of 13 mm in diameter when the hydrogen flux was 25 sccm.At this output the maximum arc power available is only 4.5 kW and the e/H-ratio is about 5.When the hydrogen flux is higher or extraction high voltage is higher,H-beam currents can reach 22 mA.However,the H-beam is very unstable with terrible sparks at extraction and acceleration gaps in this case,about five times a minute.This appears to be due to the lack of a differential pumping structure,which also results in an unexpectedly high hydrogen flux.In the experiment,the relationship between arc power and H-beam intensity was determined,also the optimal location of the four-filament structure was determined,which is obviously related to the virtual filter magnetic field distribution.At present,the emittance

关 键 词：回旋加速器 负氢离子源 多峰约束场 虚拟过滤场 

分 类 号：TL503.3[核科学技术—核技术及应用]