Design and implementation of an in-vacuum magnetic field measurement system for the TPS nonlinear in-vacuum kicker

The Taiwan Photon Source (TPS) storage ring employs a traditional four-kicker bump off-axis injection scheme, which can introduce perturbations to the stored beam during the injection phase. To address these issues and facilitate stable top-up injection, a Nonlinear In-vacuum Kicker (NIK) has been developed. This innovative device is specifically designed to produce zero magnetic fields in both the horizontal (Bx) and vertical (By) directions at the beam center, while generating a peak By field at the injection point. This field configuration ensures a transparent injection process by minimizing interference with the stored beam during injection. To accurately assess and refine the magnetic field properties of the NIK while avoiding arcing during measurements in atmospheric condition, a specialized in-vacuum magnetic field measurement system has been developed and deployed. This system enables precise mapping of the magnetic field profile over a range of excitation currents. This paper details the system’s mechanical design, fabrication methodology, and presents preliminary results from its implementation.