发表机构
Tsinghua University; Key Laboratory of Particle and Radiation Imaging, Tsinghua University, Ministry of Education（清华大学; 清华大学粒子与辐射成像教育部重点实验室）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对射频枪中高电荷下空间电荷效应导致阴极成像分辨率下降的问题，提出磁化电子束成像方法，实现10 pC电荷下逐点成像，分辨率达11 um，较非磁化方法提升近一个数量级。
AI 中文摘要
量子效率（QE）是光阴极的关键特性，其均匀性对产生高亮度电子束至关重要。阴极成像是一种原位实时的QE测绘方法，但在射频枪中，为获得足够的信噪比通常需要每束团携带高电荷。在此条件下，空间电荷效应会显著降低成像分辨率，甚至可能导致逐点阴极成像失效。本文提出一种基于磁化电子束的新型阴极成像方法，通过理论分析和束流动力学模拟验证了其可行性。结果表明，该方法可在10皮库（pC）电荷范围内实现逐点阴极成像；针对10 pC、3皮秒（ps）的束流，搭配1200高斯（Gauss）的阴极磁场，模拟显示其成像分辨率达11微米（um），较非磁化束流方法提升近一个数量级。
英文摘要
Quantum efficiency (QE) is a key property of photocathodes, and its uniformity is essential for producing high-brightness electron beams. Cathode imaging provides an \textit{in-situ} and real-time approach for QE mapping, but in RF guns, a high charge per bunch is often needed to obtain a sufficient signal-to-noise ratio. Under such conditions, space charge effects can significantly degrade the imaging resolution and may even make point-to-point cathode imaging ineffective. In this paper, we propose a novel cathode imaging method based on a magnetized electron beam. Its feasibility is examined through theoretical analysis and beam dynamics simulations. The results show that the proposed method enables point-to-point cathode imaging in the ten picocoulomb charge regime. For a 10 pC, 3ps beam with a cathode magnetic field of 1200 Gauss, simulations indicate an imaging resolution of 11 um, representing nearly an order-of-magnitude improvement over the non-magnetized beam method.
