高精度环形谱仪等时性模式的闭轨校正模拟

高精度环形谱仪（SRing）是HIAF装置的重要组成部分，闭轨校正设计是该同步加速器设计的关键部分。由于等时性模式（γ_t=1.43）线性光学水平β函数很大，磁铁场误差及安装误差会引起较大的闭轨畸变，并导致线性光学发生变化。模拟过程采用奇异值分解（SVD）算法，通过多次计算响应矩阵并计算校正铁校正量实现闭轨校正。同时考虑BPM误差的影响，并通过减少特征值使用个数降低校正铁校正量。校正后全环最大闭轨小于0.8 mm，线性光学也得到明显优化。

Closed Orbit Correction for the Isochronous Mode of Spectrometer Ring

The Spectrometer Ring (SRing), which is an important component of the High Intensity heavy-ion Accelerator Facility (HIAF), has to be optimized for the closed orbit correction system. Since the maximum horizontal β function of the isochronous mode (γ_t=1.43) is very large, the field imperfections and alignment deviations of the magnets will cause large closed orbit distortion (COD), which will result in the distortions of linear optics. Therefore, the closed orbit correction is critical to the operation of SRing. In the simulations, the Singular Value Decomposition (SVD) algorithm is adopted. The repeated correction method is applied and the response matrices are multi-calculated before each correction. The influences of BPM reading errors are analyzed. In addition, the effects of reduced singular values are analytically expressed and simulated. As a result, the closed orbits are corrected to be less than 0.8 mm, and the linear optics is also well optimized.