等时性FFAG加速器原理及关键技术研究

Isochronous FFAG (IFFAG) accelerators have highly potential applications in high power proton driver, hadron therapy and low energy electron beams, due to the breakthrough of pulse mode adopted by classical FFAGs. Considering various features in relativity of leptons and hadrons, two types of isochronous FFAGs will be studied. For relativistic beam, a unique Serpentine acceleration method is introduced into scaling FFAG. Specifically, the lattice and key parameters of a 10 MeV electron IFFAG will be designed and optimized, with higher field index and enough energy gain per turn that Serpentine channel demands. As well as the technical design and feasibility of the compact magnet and high voltage RF cavity will be implemented. For non-relativistic beam such as medium energy protons, a non-linear non-scaling IFFAG scheme will be studied with high isochronism by design and optimization of the lattice and edge focusing. Physical design of a 1 GeV proton IFFAG will be submitted. This project will bring substantial contribution to practical applications of IFFAG by research on its theory and key technologies.

新型等时性FFAG加速器可突破经典FFAG脉冲模式限制，在大功率质子驱动器、强子癌症治疗及低能电子束应用上有巨大应用价值。本项目针对轻子和强子不同相对论速度特性，拟采用两种等时性FFAG加速原理予以实现。针对相对论粒子束，将Serpentine加速方法引入至等比FFAG，以10MeV电子FFAG加速器为对象，进行磁格结构及关键参数体系设计，研究在较高磁场梯度指数和Serpentine加速所要求的单圈增益条件下，紧凑型磁铁及大电压高频腔的工程可行性和关键技术。对于中能量段质子应用，拟采用非线性非等比FFAG方案，通过磁格结构和边缘场优化设计提高等时性指标，提供1GeV等时性质子FFAG加速器物理设计方案。本项目将通过相关原理性及关键技术研究为等时性FFAG加速器面向实际应用做出实质性贡献。

基于CW连续束加速模式，等时性FFAG加速器可突破经典FFAG脉冲束流模式限制，在大功率质子驱动器、强子癌症治疗系统及电子束辐照应用方面有显著应用前景。目前世界上该类型加速原理理论与实验研究还有限。本项目针对等时性FFAG加速原理及其应用开展研究，4年来取得了较好研究成果：（1）深入研究了基于Serpentine加速方法的等比FFAG加速器原理，完成了一台9MeV等时性电子FFAG加速器物理及方案设计；（2）开展了用于大功率电子加速器的热阴极电子枪结构与束流动力学研究；（3）针对质子治疗应用，比较了等时性FFAG与回旋加速器方案，在国内首先提出了基于等时性超导回旋加速器的质子治疗系统方案，并在加速器及束线设计上取得一系列创新成果；（4）开展了关于一台10MeV浅谷型回旋加速器中心区、高频及控制系统的实验研究。.本项目在国际加速器领域有影响的学术期刊Rev. Sci. Instrum, Nucl. Instrum. Meth. A, IEEE Appl. Superconductivity及FFAG等国际会议上发表论文共11篇，获得国家专利5件授权。在国际交流方面，参加4次重要国际会议，做口头报告5次。