Development of Two Types of Cryogen Free Superconducting Magnets (5T-ϕ300min and 10T-ϕ100mm)
Part of the
Advances in Cryogenic Engineering
book series (ACRE, volume 43)
An Ic-B-T characteristic (critical current vs. magnetic field at various temperatures) for multifilamentary NbTi superconducting (SC) wire has been measured by using a conduction cooled critical current measurement apparatus up to 300A and up to 5T, in the temperature range from 5K to 7.5K.
Two types of cryogen-free (C-F) SC magnets, a large bore type and a high field type, have been designed and fabricated based on these Ic-B-T characteristics for the multifilamentary NbTi SC wire. The large bore type and the high field type magnets generated 5T and 10T stable magnetic field at the center of the room temperature bore of 300mm and 100mm diameter, respectively.
The average heat generation while energizing is obtained based on the temperature dependence of the cryocooler’s cooling capacity. This average heat generation agrees well with the hysteresis loss of the whole magnet, calculated based on the hysteresis data for the multifilamentary NbTi short sample.
KeywordsHelium Flange Neon
M. O. Hoenig, Design concepts for a mechanically refrigerated 13K superconducting magnet system, IEEE Trans. Mag. 19:880(1983).CrossRefGoogle Scholar
J. L. Wu et al., Design and testing of a high temperature superconducting current lead, IEEE Trans. Mag. 27:1861 (1991).CrossRefGoogle Scholar
T. Kuriyama et al., Development of 1 watt class 4K GM refrigerator with magnetic regenerator materials, in: Advances in Cryogenic Engineering, Vol. 39, Plenum Press, New York (1994), p. 1335.CrossRefGoogle Scholar
Bu-Xin Xu et al., A cryogen-free superconducting magnet with 95 cm warm bore for whole body MRI, IEEE Trans. Mag. 32:2637 (1996).CrossRefGoogle Scholar
K. Watanabe et al., Cryogen-free split-pair superconducting magnet with a f50 mm x 10 mm room temperature gap, in: Advances in Cryogenic Engineering, Vol. 41,Plenum Press, New York (1996), p. 319.CrossRefGoogle Scholar
T. Hasebe et al., Critical current measurement unit utilizing Bi-based oxide superconducting current leads and cryocoolers, IEEE Trans. Appl. Supercond. 5:821 (1995).CrossRefGoogle Scholar
K. Shibutani et al., Design and Fabrication of cryogen-free superconducting magnet, Proc. of the ICEC/ICMC16, Elsevier Science, (1996), p. 1129.Google Scholar
M. S. Lubell, Empirical scaling formulas for critical current and critical field for commercial NbTi, IEEE Trans. Mag. 19:754 (1983).CrossRefGoogle Scholar
C. Schmidt et al. Second VAMAS a.c. loss measurement intercomparison: a.c. magnetization measurement of hysteresis and coupling losses in NbTi multifilamentary strands, Cryogenics 37:77 (1997).CrossRefGoogle Scholar
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