Construction and Testing of the Final Focus Quadrupole R&D Magnet for the Super-KEKB Interaction Region

Super-KEKB is designed to be a next generation particle accelerator with a target luminosity of 4 times 10³⁵ cm^-2s^-1. For the interaction region, a final focus quadrupole R&D magnet was designed and constructed. The design field gradient and effective magnetic length were 40.12 T/m and 0.299 m, respectively. The magnet consists of 6 layer coils. After construction, the magnet was tested at 4.2 K and a preliminary field measurement was performed. The magnet was energized to a current of 1800 A, which corresponds to 95.8% of the conductor limit, and the quadrupole component error was 0.23 % of the design value.