2014/04/18 by Demin Zhou, Zhou, D., Jingyu Tang +5
Engineering · #Accelerator Physics (physics.acc-ph) #FOS: Physical sciences #Particle Accelerators and Free-Electron Lasers #Particle accelerators and beam dynamics #Superconducting Materials and Applications
paper · pdf · doi:10.48550/arxiv.1404.4687
openalex publication_date 2014/04/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Fringe field becomes important when one requires more accurate modeling of a ring lattice to study the long-term beam dynamics in storage rings and deal with large aperture magnets in high-intensity proton synchrotrons or accumulator rings. In this paper, a simple expression to calculate the tune shifts due to quadrupole fringe fields is derived by using Lie algebra technique. With higher-order terms included, this method is more accurate compared with the linear fringe field model used in SAD code. The method is also applied to a BEPCII lattice. Also based on the Lie algebra technique and an inverse series technique, an equivalent hard-edge model for quadrupoles is proposed, in which the model parameters are derived analytically. The model has the advantages of the direct calculation of the equivalent length and strength of a quadrupole and the easy adaptation when the strength changes. The validity of the model and its simplified version has been checked with a numerical method, and they show very good agreements.