Development of Superconducting Joints for TWC High-Jc Nb3Sn Wires for NMR Superconducting Magnet Applications
For a persistent mode high-field NMR magnet involving several Nb3Sn coils, Nb3Sn-Nb3Sn joints with extremely small resistance values are required to maintain an acceptable field-decay rate. We have successfully developed a very reliable superconducting joining technique for Teledyne Wah Chang (TWC) high critical current-density (high-J c), niobium diffusion barrier modified jelly roll (MJR) Nb3Sn wires. In this paper, the joint fabrication and test results are presented. The range of the electric resistance of the Nb3Sn-Nb3Sn joints fabricated is about 10-14 Ohms (Ω) for currents up to 500 A and less than 6 × 10-14 Ω for currents up to 1000 A in a field of about 0.03 Tesla generated by the test coil. Both the standard four-terminal and field-decay methods were used for the measurements of joint resistance. Four joints have been tested and the success rate of the tested joints is 100%.
KeywordsHall Probe Magnet Application Joint Resistance Model Coil Test Coil
Unable to display preview. Download preview PDF.
- 1.J. C.McKinnell, D. B. Smathers, M. B. Siddall, and P. M. O’Larey, Improved superconducting critical current density in modified jelly roll Nb3Sn by the application of niobium (Nb) diffusion barriers, IEEE Trans. Appl. Supercond. 5: 1768 (1995).Google Scholar
- 4.M. Suenaga, K. Tsuchiya, N. Higuchi, and K. Tachikawa, Superconducting critical-current densities of commercial multifilamentary Nb3Sn (Ti) wires made by the bronze process, Cryogenics, 25: 123 (1985).Google Scholar