Gong, Yi-Hao; Tian, Shun-Qiang; Liu, Xin-Zhong; Xuan, Shou-Zhi; Tan, Li-Yuan; Mao, Ling-Long

NUCLEAR SCIENCE AND TECHNIQUES

2024, 35, 2210-3147

Gong, Yi-Hao; Tian, Shun-Qiang; Liu, Xin-Zhong; Xuan, Shou-Zhi; Tan, Li-Yuan; Mao, Ling-Long

The round-beam operation presents many benefits for scientific experiments regarding synchrotron radiation and the weakening influences of intra-beam scattering in diffraction-limited synchrotron light sources. A round-beam generation method based on the global setting of skew quadrupoles and the application of a non-dominated sorting genetic algorithm was proposed in this study. Two schemes, including large-emittance coupling introduced via betatron coupling and vertical dispersion, were explored in a candidate lattice for an upgrade-proposal of the Shanghai synchrotron radiation facility. Emittance variations with lattice imperfections and their influence on the beam dynamics of beam optic distortions were investigated. The results demonstrated that a precise coupling control ranging from 10 to 100% was achieved under low optical distortion, whereas full-coupling generation and its robustness were achieved by our proposed method by adjusting the skew quadrupole components located in the dispersion-free sections. The Touschek lifetime increased by a factor of 2-2.5.