SuperKEKB beam final focus superconducting magnet system

Abstract

The SuperKEKB was designed and constructed as the upgraded accelerator of KEKB. In this accelerator design, the nano-beam scheme of collision was applied and a luminosity of 8 × 1035 cm−2s−1 was targeted. In the design, the beam final focus system was the key component in the accelerator hardware elements. This final focus system consists of 55 superconducting magnets. In this paper, the designs of the magnets, the cryostats and the cryogenic system are shown, and the field measurement results are reported. The SuperKEKB beam operation with the final focus system started on 2018 March 19, and the magnet quench events up to 2020 December 16 are described.