Systematic investigations and improvements of the efficiency, purity and emittance of charge bred ion beams from an ECRIS charge state booster by plasma stabilization using two frequency heating.

通过使用两种频率加热进行等离子体稳定，对来自 ECRIS 电荷态增强器的电荷孕育离子束的效率、纯度和发射率进行系统研究和改进。

• 批准号: SAPPJ-2019-00046
• 负责人: Kester, Oliver
• 金额: $ 2.91万
• 依托单位: TRIUMF
• 依托单位国家: 加拿大
• 项目类别: Subatomic Physics Envelope - Project
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=688070
• 关键词: Systematic; investigations; improvements; efficiency; purity

The TRIUMF charge state booster (CSB), based on a 14.5 GHz PHOENIX ECR ion source, raises the charge state of ions from rare isotopes prior to injection into the post accelerator linac. Therewith it allows TRIUMF the post acceleration of isotopes from elements beyond mass 30 to the medium mass range and avoids the stripping of ions at very low kinetic energies, which is not efficient in terms of transmission. An inherent issue of the CSB is that an ECR Ion Source does not operate at Ultra High Vacuum (UHV) conditions and has a significant output of background ions. That's the reason why the level of impurities in such devices is generally high which is a drawback when dealing with very low radioactive ion intensity injection. Investigations of the 1+ to n+ conversion processes in the community demonstrated that the efficiency of the process and quality of the highly charged ion beam produced by the CSB can be significantly enhanced by optimizing the plasma conditions and the beam formation in the extraction region. The ECRIS is superior to an EBIS related to the production of intense beams of rare isotopes >10^8 per second, which is required for nuclear astrophysics experiments. However, the 1+to n+ conversion rate depends on the flexibility of the injection optics, the plasma conditions and the beam formation upon ion extraction, which need to be improved and are the objective of leading edge research in this area.***The main objective of this proposal is to improve the TRIUMF CSB performance in terms of beam quality, charge breeding efficiency and beam purity, by introducing techniques which are matter of investigations in the community. The goal is to bring TRIUMF back into the international leadership in charge breeding with ECRIS devices and to deliver higher quality and new beams to the experiments at ISAC. As the injection- and the ionisation efficiency as well as the beam purity essentially depend on the plasma conditions, the two-frequency heating and the tuning of the microwave frequency, will be introduced. These techniques rely on the generation of plasma modes that allow higher plasma densities and optimum coupling of the rf-power as well as stable plasma conditions. The project described in this proposal intends to investigate systematically the charge breeding efficiency and the beam quality by***- modifying the plasma conditions using two frequency heating and frequency tuning***- beam emittance measurements and corresponding beam extraction calculations.***In addition, the CSB will be used to generate intense beams from offline samples for the first time. The significant improvement of the CSB breeding efficiency, the beam properties and additional beam production capabilities will benefit the experimental program at ISAC in particular for accelerated beam experiments. The second aspect is the training of highly qualified personnel in the field of plasma ion sources in general and on ECRIS sources.**

基于14.5 GHz Phoenix ecr离子源的TriumF电荷助推器（CSB）在注入加速器后LINAC之前，从稀有同位素升高了离子的电荷状态。因此，它允许从质量30以外的质量到中等质量范围的元素的同位素加速后加速，并避免在非常低的动能能力下剥离离子，这在传输方面并不有效。 CSB的固有问题是，ECR离子源不在超高真空（UHV）条件下运行，并且具有背景离子的显着输出。这就是为什么在处理非常低的放射性离子强度注入时，这种设备中杂质的水平通常很高。对社区中的1+到N+转换过程的研究表明，通过优化提取区域中的血浆条件和束形成，可以显着增强CSB产生的高电荷离子光束的效率和质量。 ECRIS优于与稀有同位素> 10^8的强束相关的EBI，这是核天体物理实验所需的。但是，1+至n+转换率取决于入口光学元件的柔韧性，血浆条件和离子提取时的束形成，这需要改进，并且是该区域前缘研究的目的。*** ***该提案的主要目的是通过引入社区研究问题的技术来改善束质量，电荷育种效率和光束纯度的Triumf CSB性能。目的是将Triumf带回使用ECRIS设备的国际领导层，并为ISAC的实验提供更高质量和新的光束。由于注射效率和电离效率以及梁纯度在本质上取决于血浆条件，因此将引入两频加热和微波频率的调整。这些技术依赖于血浆模式的产生，这些等离子体模式允许更高的血浆密度和最佳的RF-Power耦合以及稳定的血浆条件。该提案中描述的项目旨在通过***进行系统地研究电荷育种效率和光束质量 - 使用两种频率加热和频率调整*** - 光束发射测量和相应的光束提取计算。*** ***此外，CSB将首次使用离线样品产生强烈的光束。 CSB育种效率，束性能和额外的束生产能力的显着提高将使IS​​AC的实验计划受益，特别是对于加速束实验。第二个方面是在总体和ECRIS来源的血浆离子来源领域中对高素质人员的培训。**