Design and Optimization of a 5BA lattice for the ZIPS storage ring

Abstract: The Zhejiang Industrial Photon Source (ZIPS) is proposed as a dedicated industrial synchrotron radiation light source in Jinhua, China, to meet the growing demand of the industrial community for high-brightness synchrotron radiation while also supporting scientific research. Following the multi-bend achromat concept widely adopted in modern diffraction-limited light sources, a five-bend achromat (5BA) lattice has been designed for its storage ring, which has a circumference of 270 m, a beam energy of 2.7 GeV and 12 unit cells. By employing horizontally defocusing bends together with reverse bends, the lattice achieves a low natural emittance of 0.64 nm·rad, meeting the requirements of an industrial light source. Through multi-objective optimization of the linear lattice, favorable optical functions and a working point well separated from dangerous resonances are obtained. The nonlinear dynamics are then optimized by enlarging the dynamic aperture while suppressing the dominant geometric resonance driving terms and the amplitude-dependent tune shifts. This yields a sufficiently large on-momentum dynamic aperture and a long Touschek lifetime, ensuring efficient beam injection and stable operation. The sensitivity of the lattice to magnet misalignment and field errors is further investigated, and a complete correction scheme, comprising trajectory correction, beam-based alignment and optics correction, is applied to restore the dynamic performance degraded by these errors. The corrected lattice recovers a dynamic aperture that meets the design requirements of the ZIPS storage ring.