Critical current and n-value of Nb/sub 3/Sn conductors for the wide bore 900 MHz NMR magnet

摘要

Electrical characterization of Nb/sub 3/Sn superconductor for application in a 900 MHz wide bore NMR magnet is performed. The magnet has five coils containing bronze process niobium-tin superconductor. Short samples of each of the five conductor types are reacted in a similar manner as the coils and the critical currents are measured. The samples are mounted across a Ti-6Al-4V shunt and the tests are conducted in background fields up to 19.45 T and at temperatures of 4.2 K and 1.8 K. Descriptions of the superconductor configurations and experimental procedure are given. The measured critical current and the current-voltage relationship of each conductor as expressed by the index number (n-value) are presented.