Bunch-by-bunch position measurement with sub-micron resolution at nanoseconds separation using wideband cavity beam position monitors

Liu Yang; Xiaozhong He; Xiaoding Zhang; Kui Zhou; Ping Liu; Yi Liu; Quanhong Long; Hanbin Wang; Qing Tian; Xuming Shen; Dexin Xiao

doi:10.1063/5.0237532

Bunch-by-bunch position measurement with sub-micron resolution at nanoseconds separation using wideband cavity beam position monitors

Rev Sci Instrum. 2024 Dec 1;95(12):123304. doi: 10.1063/5.0237532.

Authors

Liu Yang¹, Xiaozhong He¹, Xiaoding Zhang¹, Kui Zhou², Ping Liu¹, Yi Liu¹, Quanhong Long¹, Hanbin Wang², Qing Tian¹, Xuming Shen², Dexin Xiao²

Affiliations

¹ Institute of Fluid Physics, China Academy of Engineering Physics, P.O. Box 919-106, Mianyang 621900, China.
² Institute of Applied Electronics, China Academy of Engineering Physics, P.O. Box 919-1007, Mianyang 621900, China.

PMID: 39704605
DOI: 10.1063/5.0237532

Abstract

We developed a wideband RF cavity beam position monitor (CBPM) with a 217 MHz bandwidth centered at the 4.875 GHz dipole mode frequency as part of the preliminary research for a high-repetition-rate hard x-ray free electron laser project at the Chinese Academy of Engineering Physics. This paper presents new results demonstrating bunch-by-bunch position measurements on electron bunches spaced by 2.3 ns (4 bunches per train). Over a measurement range of ∼100 μm, this wideband CBPM achieved a spatial resolution of 0.8 μm at a bunch charge of 80 pC. Position and tilt variations between bunches on the order of 10 μm and 10 μrad, respectively, were clearly resolved. This high spatial and temporal resolution provides a valuable tool for experimental studies on long-range wakefield effects in multi-bunch operational light sources.