Bx. Xu et al., A CRYOGEN-FREE SUPERCONDUCTING MAGNET WITH 95-CM WARM BORE FOR WHOLE-BODY MRI, IEEE transactions on magnetics, 32(4), 1996, pp. 2637-2639
A 0.5T, 95cm warm bore, cryogen-free superconducting magnet for whole
body MRI has been developed and tested. By using Nb3Sn tape supercondu
ctor, this magnet is designed to meet the same performance requirement
as existing helium cooled MRI magnets. Persistent operation with drif
t rate less than 0.1ppm/hour and a stable 5.6ppm field homogeneity in
a 30cmx40cm cylindrical volume was achieved in October 1992, The magne
t is cooled and maintained temperature of about 10K by a Gifford McMah
on(G-M) cryocooler. High quality images were produced by using this ma
gnet with the 0.5T GE SIGNA magnetic resonance imaging system.