Development of HTS Sextupole Magnet for SuperKEKB Interaction Region

The SuperKEKB project underway at KEK will increase the KEKB luminosity by 40 times using nanobeam-interaction-region focusing optics. To achieve this high luminosity, the chromaticity correction of the collision beams is crucial; thus, special sextupole magnets, which can simultaneously produce normal and skew sextupole fields, are required in the straight sections around the interaction point. As a candidate for the sextupole, a cryocooled high-temperature superconducting magnet was proposed; development has begun. Here, the basic magnet design and the results of a small coil test are presented. The test studied the quench characteristics of the REBCO-impregnated coil.