Provision for Timing Mode Users at Multi-Bend Achromat Synchrotron Light Sources

为多弯消色差同步加速器光源的定时模式用户提供服务

• 批准号: 2583706
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2583706
• 关键词: Provision; Timing; Mode; Users; Multi

A step-change in the design of electron storage-rings for synchrotron light sources is currently underway. The latest structures consist of cells of magnets with multiple bending magnets which reduce the electron beam emittance by an order of magnitude and provide a corresponding increase in the source brightness. One consequence of these designs is a substantial reduction in the electron beam lifetime. This is typically compensated for by using harmonic RF cavities to stretch the electron bunches and reduce the particle density. One drawback however is that the emitted x-ray pulses become longer than in previous designs, and the longitudinal dynamics of the circulating electron bunches become more complex. Within this context, the aim of the project is to study how best to meet the needs of timing-mode users, taking the Diamond-II storage ring as an example.Three potential methods are proposed for study. The first is to use a hybrid filling pattern, in which the ring is filled with one long train of electron bunches to provide the light for the majority of users, and a single electron bunch in a gap for those studying time-dependent phenomenon. The second would be to use 'pulse-picking by resonant excitation', in which fast magnets are used to excite vertical oscillations in a single electron bunch. The light from this bunch can then be spatially separated from the remainder for use in timing experiments. The final method would be to use the harmonic cavity to compress the electron bunches rather than stretch them. This would reduce the x-ray pulse length, improving the temporal resolution for users. For each method, particle tracking studies are required to investigate how the electrons react to the applied conditions in order to determine the equilibrium bunch properties and maximum charge before it becomes unstable.

同步辐射光源电子储存环的设计正在进行一个阶段性的变化。最新的结构由具有多个弯曲磁体的磁体单元组成，这些磁体单元将电子束发射度降低一个数量级，并提供源亮度的相应增加。这些设计的一个结果是电子束寿命的显著减少。这通常通过使用谐波RF腔来拉伸电子聚束并降低粒子密度来补偿。然而，一个缺点是发射的X射线脉冲变得比先前的设计更长，并且循环电子聚束的纵向动力学变得更复杂。在这一背景下，本项目的目的是研究如何最好地满足定时模式用户的需求，以钻石-II储存环为例，提出了三种可能的研究方法。第一种是使用混合填充模式，其中环填充有一长串电子聚束，为大多数用户提供光，而间隙中的单个电子聚束则用于研究时间依赖现象。第二种是使用“共振激发脉冲拾取”，其中快速磁铁用于激发单个电子束中的垂直振荡。然后，来自该聚束的光可以与其余的光在空间上分离，以用于定时实验。最后一种方法是使用谐振腔来压缩电子束团，而不是拉伸它们。这将减少X射线脉冲长度，提高用户的时间分辨率。对于每种方法，都需要进行粒子跟踪研究，以研究电子如何对所施加的条件作出反应，以便在电子变得不稳定之前确定平衡聚束特性和最大电荷。