The Design of a Pair of Elliptically Polarized Undulators at SSRF

The magnetic design of a pair of elliptically polarized undulators with APPLE-II type which will be used in a soft X-ray beam line for ARPES and PEEM at SSRF is presented. The undulators will cover the energy range from 20 eV to 2000 eV of arbitrary polarized light including the horizontal, vertical, elliptical and circular polarization. The quasi-periodic design to minimize the contributions of the higher harmonics of the low energy undulator is also described.