Systematic investigations and improvements of the efficiency, purity and emittance of charge bred ion beams from the TRIUMF charge state booster.

对 TRIUMF 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-2018-00023
• 负责人: Kester, Oliver
• 金额: $ 1.09万
• 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: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=655375
• 关键词: Systematic; investigations; improvements; efficiency; purity

The TRIUMF charge state booster (CSB) raises the charge state of ions from rare isotopes prior to injection into the ISAC-I linac. Therewith, it allows the post acceleration of isotopes from elements beyond mass 30 and avoids the stripping of ions at very low kinetic energies downstream the ISAC-I Radio Frequency Quadrupole (RFQ) into an A/q mass range below 7. An inherent issue of the CSB is the operation vacuum pressure. An ECRIS does not operate at Ultra High Vacuum (UHV), which is the cause of the high level of impurities in such devices, which is an issue when dealing with very low radioactive ion intensities. However, the 1+ ->n+ conversion rate depends on the flexibility of the injection optics, the plasma conditions, the plasma confinement and the beam formation upon ion extraction, which can be optimized. The ECRIS is definitely superior to an EBIS related to the production of intense beams of rare isotopes >10^9 per second. ***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 used or under investigation at other ECRIS systems. The goal is to bring TRIUMF into the international leadership in charge breeding with ECRIS devices and to deliver higher quality and new beams to the experiments. 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. 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***- variation of the plasma chamber working gas pressure, use of UHV technology associated with the control of the plasma chamber material and the support gas composition***- beam emittance measurements using a slit-slit emittance scanner and corresponding beam extraction calculations.***In addition, the CSB will be modified by adding a high temperature oven, to exploit a new type of beam delivery via the production of highly charged ion beams from samples in the solid state. The oven need to be resistive against reactive metals, in particular for Ti-isotopes. The goal is to demonstrate a lifetime of the oven for at least several days Ti operation. This can be used to deliver long lived 44Ti (t1/2 =59Y) to users at TRIUMF.***The significant improvement of the CSB 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 in particular.

TRIUMF电荷态增强器（CSB）在注入ISAC-I直线加速器之前提高稀有同位素离子的电荷态。因此，它允许来自质量超过30的元素的同位素的后加速，并避免离子在ISAC-I射频四极杆（UHF）下游以非常低的动能剥离到低于7的A/q质量范围。CSB的一个固有问题是操作真空压力。ECRIS不能在超高真空（UHV）下运行，这是此类设备中杂质含量高的原因，这在处理非常低的放射性离子强度时是一个问题。然而，1+ ->n+转换率取决于注入光学器件的灵活性、等离子体条件、等离子体约束和离子提取时的束形成，这可以被优化。在每秒产生>10^9的稀有同位素强束流方面，ECRIS绝对优于上级EBIS。* 本提案的主要目标是通过引入其他ECRIS系统使用或正在研究的技术，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。我们的目标是将TRIUMF带入ECRIS设备电荷增殖的国际领导地位，并为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。本提案中描述的项目旨在通过 *-使用两个频率加热和频率调谐 *-改变等离子体室工作气体压力，与等离子体室材料和支持气体成分的控制相关的UHV技术的使用 *-使用狭缝的射束发射度测量-狭缝发射扫描器和相应的束提取计算。此外，CSB将通过添加高温烘箱进行修改，以通过从固态样品中产生高电荷离子束来利用新型束流传输。烤箱需要对反应性金属有抵抗力，特别是对钛同位素。目的是证明烘箱的寿命至少为几天Ti操作。这可用于向TRIUMF的用户提供长寿命的44 Ti（t1/2 = 59 Y）。* CSB束流特性的显著改善和额外的束流产生能力将有利于ISAC的实验计划，特别是加速束流实验。第二个方面是在等离子体离子源领域，特别是在ECRIS源领域，培训高素质的人员。