Design and optimization of quadrupole and sextupole magnets for Shenzhen Innovation Light-source Facility storage ring

As an advanced 4^th generation synchrotron radiation facility, the Shenzhen Innovation Light-source Facility (SILF) storage ring is based on multi-bend achromat (MBA) lattices, enabling one to two orders of magnitude reduction in beam emittance compared to the 3^rd generation storage ring. This significantly enhance the radiation brightness and coherence. The multipole magnets of many types for SILF storage ring are under preliminary design, which require high integral field homogeneity. As a result, a dedicated pole tip optimization procedure with high efficiency is developed for quadrupole and sextupole magnets with Opera-2D^® python script. The procedure considers also the 3D field effect which makes the optimization more straightforward. In this paper, the design of the quadrupole and sextupole magnets for SILF storage ring is first presented, followed by a detailed description of the implemented pole shape optimization method.