A practical 2.45-GHz microwave-driven Cs-free H^- source was improved based on the experimental H^- source at Peking University（PKU）. Several structural improvements were implemented to meet the practical requiremen...A practical 2.45-GHz microwave-driven Cs-free H^- source was improved based on the experimental H^- source at Peking University（PKU）. Several structural improvements were implemented to meet the practical requirements of Xi＇an Proton Application Facility（XiPaf）. Firstly, the plasma chamber size was optimized to enhance the plasma intensity and stability. Secondly, the filter magnetic field and electron deflecting magnetic field were enhanced to reduce co-extracted electrons. Thirdly, a new two-electrode extraction system with farther electrode gap and enhanced water cooling ability to diminish spark and sputter during beam extraction was applied. At last, the direct H^- current measuring method was adopted by the arrangement of a new pair of bending magnets before Faraday cup（FC） to remove residual electrons. With these improvements, electron cyclotron resonance（ECR） magnetic field optimization experiments and operation parameter variation experiments were carried out on the H^- ion source and a maximum 8.5-mA pure H^- beam was extracted at 50 kV with the time structure of 100 Hz/0.3 ms. The root-mean-square（RMS） emittance of the beam is 0.25 Π·mm·mrad. This improved H^- source and extraction system were maintenance-free for more than 200 hours in operation.展开更多
空间推进所用的电子回旋共振离子源(ECRIS)应具有体积小、效率高的特点.本文研究的ECRIS使用永磁体环产生磁场,有效减小了体积,该离子源利用微波在磁场中加热电子,电子与中性气体发生电离碰撞产生等离子体.磁场在微波加热电子的过程中...空间推进所用的电子回旋共振离子源(ECRIS)应具有体积小、效率高的特点.本文研究的ECRIS使用永磁体环产生磁场,有效减小了体积,该离子源利用微波在磁场中加热电子,电子与中性气体发生电离碰撞产生等离子体.磁场在微波加热电子的过程中起关键作用,同时影响离子源内等离子体的约束和输运.通过比较四种磁路结构离子源的离子电流引出特性来研究磁场对10 cm ECRIS性能的影响.实验发现:在使用氩气的条件下,特定结构的离子源可引出160 mA的离子电流,最高推进剂利用率达60%,最小放电损耗为120 W·A^(-1);所有离子源均存在多个工作状态,工作状态在微波功率、气体流量、引出电压变化时会发生突变.离子源发生状态突变时的微波功率、气体流量的大小与离子源内磁体的位置有关.通过比较不同离子源的引出离子束流、放电损耗、气体利用率、工作稳定性的差异,归纳了磁场结构对此种ECRIS引出特性的影响规律,分析了其中的机理.实验结果表明:保持输入微波功率、气体流量、引出电压不变时,增大共振区的范围、减小共振区到栅极的距离,离子源能引出更大的离子电流;减小共振区到微波功率入口、气体入口的距离能降低维持离子源高状态所需的最小微波功率和最小气体流量,提高气体利用率,但会导致放电损耗增大.研究结果有助于深化对此类离子源工作过程的认识,为其设计和性能优化提供参考.展开更多
目的:探讨医用回旋加速器的粒子产生与运动机制,为实际工作提供技术支持。方法 :结合设备使用说明书Qilin service manual-maintenance part 10:ion source and central region和Qilin service manual-maintenance part13:extraction sy...目的:探讨医用回旋加速器的粒子产生与运动机制,为实际工作提供技术支持。方法 :结合设备使用说明书Qilin service manual-maintenance part 10:ion source and central region和Qilin service manual-maintenance part13:extraction system以及加速器领域相关参考文献,分析离子源、电磁场和束流引出系统的功能及其运行方法。结果:提出回旋加速器完成对粒子加速具备的必要条件:一是离子源内部形成等离子体,二是电磁场作用,三是经过束流引出系统引导束流轰击至指定靶位,四是需要一个真空系统以及一个供电和控制系统。结论:粒子的产生与运动以及保证束流的品质需要在各个子系统紧密配合下完成,准确理解医用回旋加速器的粒子产生与运动机制对于正确使用回旋加速器具有重要作用。展开更多
ECRIS’s dedicated to radioactive ion production must be as efficient as those used for production of stable elements,but in addition they are subject to more specific constraints such as radiation hardness, short ato...ECRIS’s dedicated to radioactive ion production must be as efficient as those used for production of stable elements,but in addition they are subject to more specific constraints such as radiation hardness, short atom-to-ion transformation time,beam purity and low cost.Up to now,different target/ion-source systems(TISSs)have been designed,using singly-charged ECRISs,multi-charged ion sources or an association of singly-to-multi-charged ECRISs.The main goals,constraints and advantages of different existing ECR setups will be compared before a more detailed description is given of the one designed for the SPIRALⅡproject and its future improvements.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11775007 and 11575013)
文摘A practical 2.45-GHz microwave-driven Cs-free H^- source was improved based on the experimental H^- source at Peking University（PKU）. Several structural improvements were implemented to meet the practical requirements of Xi＇an Proton Application Facility（XiPaf）. Firstly, the plasma chamber size was optimized to enhance the plasma intensity and stability. Secondly, the filter magnetic field and electron deflecting magnetic field were enhanced to reduce co-extracted electrons. Thirdly, a new two-electrode extraction system with farther electrode gap and enhanced water cooling ability to diminish spark and sputter during beam extraction was applied. At last, the direct H^- current measuring method was adopted by the arrangement of a new pair of bending magnets before Faraday cup（FC） to remove residual electrons. With these improvements, electron cyclotron resonance（ECR） magnetic field optimization experiments and operation parameter variation experiments were carried out on the H^- ion source and a maximum 8.5-mA pure H^- beam was extracted at 50 kV with the time structure of 100 Hz/0.3 ms. The root-mean-square（RMS） emittance of the beam is 0.25 Π·mm·mrad. This improved H^- source and extraction system were maintenance-free for more than 200 hours in operation.
文摘空间推进所用的电子回旋共振离子源(ECRIS)应具有体积小、效率高的特点.本文研究的ECRIS使用永磁体环产生磁场,有效减小了体积,该离子源利用微波在磁场中加热电子,电子与中性气体发生电离碰撞产生等离子体.磁场在微波加热电子的过程中起关键作用,同时影响离子源内等离子体的约束和输运.通过比较四种磁路结构离子源的离子电流引出特性来研究磁场对10 cm ECRIS性能的影响.实验发现:在使用氩气的条件下,特定结构的离子源可引出160 mA的离子电流,最高推进剂利用率达60%,最小放电损耗为120 W·A^(-1);所有离子源均存在多个工作状态,工作状态在微波功率、气体流量、引出电压变化时会发生突变.离子源发生状态突变时的微波功率、气体流量的大小与离子源内磁体的位置有关.通过比较不同离子源的引出离子束流、放电损耗、气体利用率、工作稳定性的差异,归纳了磁场结构对此种ECRIS引出特性的影响规律,分析了其中的机理.实验结果表明:保持输入微波功率、气体流量、引出电压不变时,增大共振区的范围、减小共振区到栅极的距离,离子源能引出更大的离子电流;减小共振区到微波功率入口、气体入口的距离能降低维持离子源高状态所需的最小微波功率和最小气体流量,提高气体利用率,但会导致放电损耗增大.研究结果有助于深化对此类离子源工作过程的认识,为其设计和性能优化提供参考.
文摘目的:探讨医用回旋加速器的粒子产生与运动机制,为实际工作提供技术支持。方法 :结合设备使用说明书Qilin service manual-maintenance part 10:ion source and central region和Qilin service manual-maintenance part13:extraction system以及加速器领域相关参考文献,分析离子源、电磁场和束流引出系统的功能及其运行方法。结果:提出回旋加速器完成对粒子加速具备的必要条件:一是离子源内部形成等离子体,二是电磁场作用,三是经过束流引出系统引导束流轰击至指定靶位,四是需要一个真空系统以及一个供电和控制系统。结论:粒子的产生与运动以及保证束流的品质需要在各个子系统紧密配合下完成,准确理解医用回旋加速器的粒子产生与运动机制对于正确使用回旋加速器具有重要作用。
文摘ECRIS’s dedicated to radioactive ion production must be as efficient as those used for production of stable elements,but in addition they are subject to more specific constraints such as radiation hardness, short atom-to-ion transformation time,beam purity and low cost.Up to now,different target/ion-source systems(TISSs)have been designed,using singly-charged ECRISs,multi-charged ion sources or an association of singly-to-multi-charged ECRISs.The main goals,constraints and advantages of different existing ECR setups will be compared before a more detailed description is given of the one designed for the SPIRALⅡproject and its future improvements.
