Design and Construction of the Magnet Cryostats for the SuperKEKB Interaction Region

The beam final focus system in the SuperKEKB interaction region consists of 55 superconducting magnets including eight main quadrupole magnets. Two cryostats for these magnets were required to be operated inside the Belle-II particle detector because of the magnet positions by the SuperKEKB beam optics. The cryostats were designed under constraints of the space and the electromagnetic forces with Belle-II. Construction of the cryostats was completed, and they were installed into the SuperKEKB interaction region. Cold tests of the cryostats were performed, and all magnets were successfully excited at the operation currents. In this paper, the design and the construction of the cryostats are presented.