Speaker
Description
After we have developed the 25 T cryogen-free superconducting magnet (25 T-CSM) with a Bi2223 insert, Nb3Sn and NbTi Rutherford outsert coils [1], we are planning two projects on high field cryogen-free superconducting magnets. One is an upgrade of the 25T-CSM to 30 T with replacing the present Bi2223 insert to an REBCO one [2]. The other plan is to build a new high field CSM beyond 30 T. For these two projects, two REBCO tapes co-wound pancake coils with an additional Hastelloy tape for reinforcement are considered as the insert coil. The primitive design of a 33 T cryogen-free superconducting magnet with a 32 mm room temperature bore was done as well as the REBCO insert for the upgrading, on the basis of the 25 T-CSM. For the REBCO insert, a EuBCO with BHO tape, which is developed by Fujikura, is a candidate [3]. In case of the LTS outsert, the NbTi and the high strength Nb3Sn Rutherford cables are used similarly to the 25T-CSM. To increase the efficiency of the LTS coil, the improvement of mechanical strength of CuNb reinforced Nb3Sn strands are carried out with Furukawa. In addition, the two REBCO tape co-wound pancake R&D coils with and without additional Hastelloy reinforcement were tested. The effects of coupling of two tapes and of large electromechanical stress on the R&D coils will be discussed in the presentation as well the overview of the projects.
[1] S. Awaji et al., SuST, 30 (2017) 065001.
[2] S. Awaji et al., IEEE TAS (2019) in press.
[3] S. Fujita et al., IEEE TAS (2019) in press.
