Toshie Takeuchi

Superconducting bending magnets for compact synchrotron radiation source

A 180 degrees superconducting magnet has been constructed for a synchrotron radiation source. The authors describe the superconducting magnet design and some component test results for the compact synchrotron radiation source. The magnetic field at the electron orbit is 4.5 T. The bending radius is 0.593 m. The magnet has several features such as low liquid helium consumption ratio, persistent current operation, high homogeneous magnetic fields, and leakage flux shielding by the iron core surrounding the cryostat. Component tests of persistent current switches of 15 Omega and 3 Omega and a superconducting joint test have been performed.<<ETX>>

3-D nonlinear transient electromagnetic analysis of short circuit electromagnetic forces in a three-phase enclosure-type gas insulated bus

An accurate analysis of short circuit electromagnetic forces in a three-phase enclosure-type gas insulated bus (GIB) has been performed. The analysis clarified the effects of the eddy currents (skin effect) and the nonlinear permeability on the materials. The calculated magnetic fields agree with the measured fields. The electromagnetic force analysis considering the skin effect and the nonlinear permeability of the magnetic materials is important in view of reducing the GIB size.

A conceptual design of a superconducting magnet for MAGLEV using a Bi-based high-Tc tape

A conceptual design of a superconducting magnet for MAGLEV using a Bi-based high-Tc superconducting tape ((BiPb)/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub 8/-Ag) is studied. In this study, the structure of conductor and coil, AC loss, stability, current lead, persistent current switch, cryostat structure and cooling system are estimated. The characteristics of the design are as follows: (1) the superconducting coil is cooled by a refrigerator at 20 K and is operated by persistent mode; (2) the coil is constructed by 6 pieces of double pancake coils, and each pancake coil is graded by changing conductor size; (3) the temperature rise of the coil is about 2 K due to AC loss; and (4) the superconducting stability is very high.<<ETX>>

Field measurements of superconducting bending magnets for compact storage ring

We have constructed 180 degree superconducting bending magnets for compact electron storage rings and tests of magnetic field qualities of the magnets have been performed. Measured field qualities are; (1) high field homogeneity (normalized field errors are less than 1/spl times/10/sup -3/ over the electron beam aperture), (2) high field stability (the decay of the field is less than 0.1%/year) at persistent current mode of 3.5 T, (3) small gradient of coil axis (the averaged value is 0.5 mrad), and (4) small difference of the fields between two magnets (the difference is less than /spl plusmn/1/spl times/10/sup -3/). From the tests of field qualities, we confirm that the magnets have good performance for electron beam storage. An electron beam of 600 MeV can be stored.<<ETX>>