Magnetic Measurement and Shimming for EPU100 of SSRF

An elliptically polarizing undulator EPU100 has been built in Shanghai Synchrotron Radiation Facility (SSRF) recently. This undulator adopts the APPLE-II type magnet configuration and has a total length 4.3 m with a period of 100 mm. It was designed to provide synchrotron radiations with various polarizations including the circular, the elliptical, the horizontally linear and the vertically linear polarizations. The magnetic measurement has been finished by using a 3-dimensional Hall probes and flipping coil system. This paper details the method of the magnetic measurement and shimming for EPU100. The maximum R.M.S. phase errors 3.8 and 2.2 are calculated from the measured magnetic fields respectively in the horizontally and vertically linear polarization modes.