Magnetic Field Correction Methods for Hybrid Permanent Magnet and Superconducting Undulators

摘要

This work describes tuning methods used at Lawrence Berkeley National Laboratory (LBNL) for hybrid permanent magnet and superconducting undulators (SCUs). The work on the hybrid permanent magnet undulators is intended for the LCLS-II project, where a large number of devices have to be built and tuned in an efficient manner [1]. Pole position adjustments have been successfully used for tuning of the European XFEL undulators [2–3]. The necessary features for these adjustments were built into the magnetic module design. For the LCSLII project, a similar approach has been taken; however, more tuning methods have been considered in order to further reduce the gap dependence of errors in the undulators. The main focus of the work presented here is to analyze and design tuning methods that allow for effective error cancellation over a large gap range. The analysis tools that have been developed to rapidly determine the gap scaling of errors will be presented. The magnet module designs that incorporate these tuning methods will also be described.