Graduate Research at Michigan State University to Push the Intensity Frontier and Support Accelerator Science

该项目将推动超导离子加速器产生的离子束强度的前沿。高加速器性能需要明亮、连续的离子源，并且为此，离子加速器通常使用可以被有效加速的高电荷态离子源。 此类源称为电子回旋共振源或ECR源，非常复杂，有丰富的物理学有待探索。在本计画中，将研究导致ECR源操作不可靠的因素。诊断将系统地收集信息，以更好地理解，缓解和控制可靠性问题。这项研究将在密歇根州立大学进行，在那里它将有助于提高现有离子源的性能。本项目将培养一名加速器物理技术博士研究生。为了保证连续波超导射频直线加速器的束流相空间的稳定性和紧凑性，ECR源必须连续注入低漂移、稳定输出的离子束。 在该项目中，将对国家超导回旋加速器实验室（NSCL）和稀有同位素束设施（FRIB）的ECR源进行仪器化，以测量关键系统组件中温度与电流输出的相关性。 将开发数据记录系统，识别漂移相关性，并测试缓解措施。 在高强度ECR操作中也观察到快速等离子体不稳定性，并且可以导致束流中约25%或更多的振荡，具有潜在的机器损坏。 这些不稳定性将研究与FRIB和NSCL源使用较高的电荷状态离子，其中不稳定性的理解将通过分析研究，简单的参数模型的开发，并与其他研究小组的协同合作得到改善。 该项目的时间轴将涵盖三年，与FRIB前端的早期调试活动一致，并利用FRIB硬件。

This project will push the frontier in intensity of ion beams produced by superconducting ion accelerators. High accelerator performance requires a bright, continuous source of ions, and for that ion accelerators typically use sources of high-charge-state ions which can be efficiently accelerated. Such sources, called Electron Cyclotron Resonance or ECR sources, are complex with rich physics to be explored. In this project, factors leading to unreliable ECR source operation will be studied. Diagnostics will systematically gather information to better understand, mitigate, and control reliability issues. This research will be carried out at Michigan State University, where it will help to improve performance of existing ion sources. This project will train one PhD graduate student in accelerator physics technology. To maintain a stable and compact beam phase-space for reliable machine operation of continuous wave superconducting radio-frequency (SRF) linacs, ECR sources must continuously inject ion beams with low drifts and stable output. In this project, ECR sources at the National Superconducting Cyclotron Laboratory (NSCL) and the Facility for Rare Isotope Beams (FRIB) will be instrumented to measure correlations of temperature in key system components with the current output. A data logging system will be developed, drift correlations identified, and mitigations will be tested. Fast plasma instabilities are also observed in high intensity ECR operation and can lead to ~25% or more oscillations in beam current with potential machine damage. These instabilities will be studied with the FRIB and NSCL sources using higher-charge-state ions, where understanding of the instability will be improved through analytical studies, development of simple parametric models, and synergetic collaboration with other research groups. The timeline of the project will cover three years and is consistent with early commissioning activities on the FRIB front-end and leverages FRIB hardware.