通过阴极回撤实现热发射度隔离
Thermal Emittance Isolation by Cathode Retraction
AI总结：
本文提出将阴极回撤与双缝发射度测量技术结合，以隔离并直接测量电子束热发射度，并在LCLS-II-HE低发射度注入器上验证了该方法可生成高分辨率相空间分布图，同时证明阴极回撤可作为优化光注入器性能的额外工具。
摘要：
在这项工作中，提出将阴极回撤与双缝发射度测量技术相结合，作为一种先进手段，用于单独修正发射度增长分量，特别是射频（rf）注入器边缘场，以隔离并直接测量热发射度——电子束的基本束流发射度指标。以LCLS-II-HE低发射度注入器（LEI）为案例进行研究，该注入器是为LCLS-II HE升级而设计的最先进的超导射频（SRF）电子枪，用以展示双缝技术的威力。特别地，证明了生成一个由电子束团本征发射度主导的高分辨率相空间分布图是可能的。这一结果超越了螺线管扫描所提供的常规单参数分布表征（例如RMS发射度和Twiss参数）。使该技术得以实现（并最终具有实际用途）的一个关键特征是能够回撤阴极，因为它提供了补偿射频（rf）散焦的能力。文中展示了阴极回撤如何作为一项额外的优化工具，用于调整光注入器的常规性能。我们认为，可变位置阴极可能是一种在多个参数区间内优化光注入器性能的有用方法。
英文摘要：
In this work, a combination of cathode retraction and two-slit emittance measurement technique is proposed as an advanced means to individually modify emittance growth components, specifically, rf injector fringe fields, to isolate and directly measure the thermal emittance, the fundamental beam emittance metric for an electron beam. A case study of the LCLS-II-HE Low Emittance Injector (LEI), a state-of-the-art superconducting radiofrequency (SRF) gun, designed for LCLS-II HE upgrade is used to showcase the power of the two-slit technique. Particularly, it is demonstrated that generating a high resolution phase-space distribution map, dominated by the intrinsic emittance of the electron bunch, is possible. This result goes beyond the normal single-parameter distribution characterizations (e.g. RMS emittance and Twiss parameters) provided by the solenoid scan. One key feature making this technique work (and in the end practically useful) is the ability to retract the cathode, because it provides the ability to compensate for radiofrequency (rf) de-focusing. It is demonstrated how the cathode retraction can serve as an additional optimisation tool for tailoring the routine performance of the photoinjector. We posit that a variable position cathode may be a useful method for optimizing photoinjector performance across multiple parameters regimes.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
