Superconducting Magnet System for Final-Focusing Beams in the SuperKEKB

The SuperKEKB electron-positron collider is an accelerator that has been upgraded for the KEKB. This collider is designed to explore New Physics beyond the Standard Model of particle physics in the B meson regime. The target of SuperKEKB is to attain a luminosity that is 40 times higher than that of the KEKB. To accomplish this, a new beam final focus system of the superconducting magnets was constructed based on the accelerator design of “nano beam scheme”. The system has the extremely significant function of squeezing beams to 0.05 μm from 1 μm in the KEKB, and the luminosity is expected to increase to a value 20 times higher through this process. SuperKEKB has completed Phase-2 beam operation, and the first beam collision was observed on April 26th, 2018. This paper describes the superconducting magnets and cryostat system for focusing beams at the interaction point.