Progress in the development of a 25Â T all superconducting NMR magnet

The ReBCO insert with NI technology, designed with 16 dry-wound DPs, has the inner diameter, outer diameter, and height of 32 mm, 106 mm, and 160 mm, respectively. A DP showing low performance at 77 K was got rid of the assembly and the finally assembled ReBCO insert has the inner diameter of 32 mm, outer diameter of 104 mm and height of 150 mm. Preliminary test shows that the ReBCO can generate a maximum central field of 9 T, 4.2 K in the 15 T background field. We still found bad DP-DP splice joints and premature quenches during the test. Next step on the project is to repair the insert and lower the current density at the top/bottom of the insert to improve the operation margin. Design, fabrication and test of the ReBCO insert are mainly presented in this paper.