Development of 1 GHz superconducting NMR magnet at TML/NRIM

Development of a 1 GHz superconducting NMR magnet is in progress at the Tsu kuba Magnet Laboratory of the National Research Institute for Metals. The m agnet will consist of two parts. The outer magnet of LTS coils is designed to generate a field of 21.1 T (900 MHz) in persistent current mode. The inn er coil is designed to generate an additional 2.4 T, resulting in a central field of 23.5 T (1 GHz) in a 54 mm diameter bore at room temperature. As a high-resolution NMR magnet, field stability as well as field homogeneity i s very important, which is especially difficult to achieve in the inner coi l when exposed to extremely high magnetic fields that superconducting magne ts have not yet encountered. The engineering design is complete and fabrica tion of the superconductors has begun. This report presents the results of the engineering design and R&D studies on the candidate superconductors for the inner coil, such as BSCCO, and improved Nb3A1 and Nb3Sn.