Magnetic optimization of long epus at nsls-ii

The Soft Inelastic X-ray scattering (SIX) and the Electron-Spectro-Microscopy (ESM) are two beamlines under construction at National Synchrotron Light Source-II (NSLS-II). The specifics of these two beamlines required the use of two long Advanced Planar Polarized Light Emitter-II (APPLE-II) undulators, as a source that provides both circularly and vertically polarized radiation. Thus, we designed 3.5 m and 2.7m long APPLE-II type undulators for SIX and ESM. The NSLS-II ID group is responsible for the magnetic optimization of these two long undulators. In this paper, we first summarize the APPLE-II magnetic and mechanical design. Then, we discuss the magnetic performance of the first APPLE-II achieved with the shimming performed at BNL.