Magnet-Sorting Algorithm for an Elliptically Polarized Undulator at TPS

An effective initial sorting of permanent magnets can decrease the adverse effects of magnetic inhomogeneities and the imperfect geometry of blocks on the performance of an undulator. A sorting algorithm, based on simulated annealing, for the TPS EPU is implemented. The algorithm takes into account the magnetization of the blocks and the interactions between magnets. The field quality, including multipole, phase error, and particle trajectory, was optimized to within the specified tolerance. In this paper, we describe the sorting procedure and demonstrate the optimization results.