| 摘要 |
PURPOSE:To obtain excellent characteristics in a specified magnetic field range at a specified temperature of liquid helium without decrease of critical current, by employing an oxide superconductor having high critical magnetic field as a superconductor for high magnetic field superconducting magnet. CONSTITUTION:A bias magnetic field generating magnet 4 is constituted by first and second outer magnets 1 and 2, so that bias magnetic field is generated thereby. An inner magnet 5 is produced as a superconducting magnet for high magnetic field by winding a Y-Ba-Cu oxide superconductor. According to the Jc-B curve representing relation between critical current (Jc) And magnetic flux density (b) of the Y-Ba-Cu oxide, this material abruptly decreases its Jc with increase of B at a temperature of 77K. At a temperature of 4.2K, however, Jc does not decrease when B is about 2T or more, Further, it is shown that this material has B of 110T at 0K. Accordingly, critical magnetic field of the material can be estimated to be 80T or more when a temperature of liquid He is 4.2K, for example. Thus, within a magnetic field range of 18-50T, it is possible to obtain operating current for the superconducting inner coil with a margin of about 50% with respect to current Jc. |
