Beam-Driven Accelerator Studies

加速器科学和技术的进步需要使基本粒子物理学的新发现成为可能，实现这一目标的一条途径是设计新的加速器设计，以提供高效率的高加速率。 该实验研究项目在理论和计算支持下，旨在确认基于双束概念的新加速器设计的基本方面，其中一个具有大量粒子的束提供能量，以将较少粒子的束加速到较高能量。 追求这样的路径是必不可少的，以增加未来以可接受的成本建造电子与正电子碰撞的数十万亿电子伏（即百万电子伏）机器的可能性。该项目位于耶鲁大学束流物理实验室，将支持建设一个独特的大学设施，以探索一系列额外的束流驱动加速想法，并将为下一代急需的加速器科学家提供培训机会，包括学生，博士后研究人员和初级教师。该项目的技术目标是：（1）配置具有相关联的射束传输线的500-kV电子枪以提供长的高电流多束流聚束串;以及（2）应用这样的聚束串作为驱动射束以激发失谐的双模腔结构，以实现高加速度梯度和高Transformer比。该结构的两个微波模式将被驱动光束激发，其中较高模式的频率等于最低基模的频率的三倍。这两种模式的频率失谐远离驱动光束或其三次谐波的频率，以支持腔中电磁场的非常规时空分布。这种策略预计将允许加速器在高加速度梯度下工作，具有低故障率和极大的系统简化。预期的未来结果是一个可行的加速器结构设计的发展，可以支持一个新的双束加速方案，两个光束移动沿着相同的中心轴的结构。

Advancement in accelerator science and technology is required to make possible new discoveries in elementary particle physics, and one path towards that goal is to devise new accelerator designs to provide high acceleration rates with high efficiency. This experimental research project, with theoretical and computational support, aims to confirm fundamental aspects of a new accelerator design based on a two-beam concept whereby one beam with a large number of particles provides energy to accelerate a beam of fewer particles to a higher energy. The pursuit of paths such as this is essential to increase the likelihood that a future multiple-tera-electron-volt (i.e. a million-million electron volt) machine to collide electrons with positrons will be built at an acceptable cost. This project, based at the Yale University Beam Physics Laboratory, will support construction of a unique university-based facility for exploring a range of additional beam-driven acceleration ideas and will provide training opportunities for the next generation of much-needed accelerator scientists, including students, postdoctoral researchers, and junior faculty.The technical objectives of this project are: (1) to configure a 500-kV electron gun with an associated beam transport line to provide a long high-current multi-Amp bunch train; and (2) to apply such a bunch train as the drive beam to excite a detuned bimodal cavity structure to achieve high acceleration gradient and high transformer ratio. Two microwave modes of this structure will be excited by the drive beam, with the frequency of the higher mode equal to three times that of the lowest fundamental mode. The frequencies of these two modes are detuned away from that of the drive beam or its third-harmonic, to support unconventional spatiotemporal distributions of the electromagnetic fields in the cavities. This strategy is predicted to allow the accelerator to operate at high acceleration gradient with low breakdown rates and great system simplification. The intended future outcome is the evolution of a viable accelerator structure design that can support a novel two-beam acceleration scheme with both beams moving along the same central axis in the structure.