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.

TRIUMF电荷状态增强器（CSB）基于14.5 GHz PHOENIX ECR离子源，在注入后加速器直线加速器之前提高稀有同位素离子的电荷状态。因此，它允许TRIUMF将同位素从质量超过30的元素后加速到中等质量范围，并避免在非常低的动能下剥离离子，这在传输方面是无效的。CSB的一个固有问题是ECR离子源不能在超高真空（UHV）条件下操作，并且具有显著的背景离子输出。这就是为什么这种装置中的杂质水平通常很高的原因，这在处理非常低的放射性离子强度注入时是一个缺点。社区中的1+到n+转换过程的调查表明，该过程的效率和质量的高电荷的离子束产生的CSB可以显着提高通过优化等离子体条件和束形成的提取区域。ECRIS比EBIS更上级，EBIS能产生每秒大于10 ^8的稀有同位素强束，这是核天体物理实验所需要的。然而，1+到n+的转化率取决于注入光学器件的灵活性、等离子体条件和离子提取时的束形成，这些都需要改进，并且是该领域前沿研究的目标。本提案的主要目标是通过引入社区调查的技术，改善TRIUMF CSB在光束质量、电荷增殖效率和光束纯度方面的性能。其目标是使TRIUMF重新成为ECRIS设备在电荷增殖方面的国际领导者，并为ISAC的实验提供更高质量的新光束。由于注入和电离效率以及束纯度基本上取决于等离子体条件，因此将引入双频加热和微波频率的调谐。这些技术依赖于等离子体模式的产生，其允许更高的等离子体密度和射频功率的最佳耦合以及稳定的等离子体条件。本提案中所述项目旨在通过 *-此外，CSB将首次用于从离线样品中产生强光束。CSB增殖效率、束流特性和额外的束流产生能力的显著提高将有利于ISAC的实验计划，特别是加速束流实验。第二个方面是培训一般等离子体离子源领域和ECRIS源领域的高素质人员。

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.**