基于新型FFA的CEBAF升级至22 GeV白皮书
White Paper on a Novel FFA-Based CEBAF Upgrade to 22 GeV
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中文总结 AI 辅助
本白皮书提出一种采用Halbach式永磁体FFA弧段的CEBAF升级至22 GeV的概念设计，基于CBETA的八次通过能量回收技术，经束流动力学等验证，保留CEBAF多厅等核心能力。
中文摘要 AI 辅助
我们提出了一种具有成本效益的连续电子束加速器设施（CEBAF）升级至22 GeV的概念设计，该设计采用由Halbach式永磁体构建的非缩放固定场交替梯度（FFA）弧段。该设计基于康奈尔-布鲁克海文国家实验室（BNL）CBETA测试加速器的八次通过能量回收演示，将最高能量的再循环弧段替换为一对FFA弧段，可同时传输跨越两倍动量范围的六次通过。我们描述了机器布局，包括注入器、再循环直线加速器、展束器与合束器、FFA弧段、分束器、过渡区及引出区，同时介绍了涵盖发射度增长、同步辐射驱动去极化及轨道校正的束流动力学验证研究，并总结了永磁体设计、原型制作及抗辐射性结果。本白皮书记录了支撑分阶段实现22 GeV路径的加速器物理基础，该路径保留了CEBAF的多厅、高亮度、极化束流能力。
英文摘要
We present a conceptual design for a cost-effective upgrade of the Continuous Electron Beam Accelerator Facility (CEBAF) to 22 GeV using non-scaling fixed-field alternating-gradient (FFA) arcs built from Halbach-style permanent magnets. Building on the eight-pass energy-recovery demonstration at the Cornell--BNL CBETA test accelerator, the design replaces the highest-energy recirculation arcs with a pair of FFA arcs that simultaneously transport six passes spanning a factor-of-two momentum range. We describe the machine layout; including the injector, recirculating linacs, spreaders and recombiners, FFA arcs, splitters, transition and extraction regions; together with beam-dynamics validation studies covering emittance growth, synchrotron-radiation-driven depolarization, and orbit correction, and we summarize permanent-magnet design, prototyping, and radiation-resiliency results. This white paper documents the accelerator physics underpinning a staged path to 22 GeV that preserves CEBAF's multi-hall, high-luminosity, polarized-beam capabilities.
