| 摘要 |
PURPOSE: To provide a method which restrains a trapped magnetic flux from being dropped with time when a superconducting tube is manufactured and to provide a superconducting tube in which a drop with time, in a trapped magnetic flux is small. CONSTITUTION: A cylindrical superconductor is cooled down to a critical temperature or lower, a magnetic field Bb at Betake-off <B<Bemax is applied in the axial direction of the tube from the outside of the superconductor, an external magnetic field is reduced to a zero magnetic field, and the superconductor is magnetized. At this time, Betake-off is an externally applied magnetic field at a time when an external magnetic field starts to enter the inside of the superconducting tube, and Bemax is an externally applied magnetic field at a time when a magnetic field which has entered the inside of the superconductor tube becomes equal to a maximum magnetic field Bimax which can be trapped. By this method, a special device is not required in addition to an exciting magnet, and the trapped magnetic field can be maintained stably, safely and without giving a burden to a magnet for excitation. |
