Title :
Fabrication of superconducting joints for Bi-2212 pancake coils
Author :
Shibutani, K. ; Egi, T. ; Hayashi, S. ; Fukumoto, Y. ; Shigaki, I. ; Masuda, Y. ; Ogawa, R. ; Kawate, Y.
fDate :
3/1/1993 12:00:00 AM
Abstract :
To evaluate the possibility of persistent current operation for NMR/MRI using a Bi/sub 2/Sr/sub 2/CaCuO/sub 8/ (Bi-2212) superconductor at 4.2 K, the temperature dependence of magnetic relaxation of the single crystal has been measured. It was found that the operating current must be one-fourth of J/sub c/ at 4.2 K to satisfy the stability condition for NMR/MRI operation ( Delta J/J less than 0.005 ppm/h). A superconducting coil made of Bi-2212 silver-sheathed wire was fabricated by the partial melt growth process. The authors were successful in generating 1.60 T in a zero external magnetic field at 4.2 K with a coil made of silver-sheathed Bi-2212 tape which was 100- mu m thick, 10-mm wide and 150-m long. Superconducting jointed pancake coils with critical current reaching 80 A in an external magnetic field of 1.0 T at 4.2 K were also fabricated.<>
Keywords :
bismuth compounds; calcium compounds; composite superconductors; critical current density (superconductivity); crystal growth from melt; high-temperature superconductors; magnetic relaxation; nuclear magnetic resonance; silver; strontium compounds; superconducting magnets; superconductive tunnelling; 1 to 1.6 T; 10 mm; 100 micron; 150 m; 4.2 K; Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub x/-Ag; NMR/MRI; critical current; high temperature superconductivity; jointed pancake coils; magnetic relaxation; partial melt growth process; persistent current operation; superconducting coil; temperature dependence; Bismuth; Fabrication; Magnetic fields; Magnetic resonance imaging; Nuclear magnetic resonance; Persistent currents; Strontium; Superconducting coils; Superconducting magnets; Temperature dependence;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
