Development and study of precision superconducting dipole magnets

The SPD-3 and SPD-3' 700mm long superconducting dipole magnets with internal and external diameters of 85 and 155mm, correspondingly, are described as well as test results are presented. A nominal magnet field is 40kOe for 2100A current. Accumulated energy for a nominal current value is 66kJ. Windings are made of 10μkm dia. Nb-Ti filaments. Magnet tests have shown, that relative field inhomogeneity does not exceed 4x10sup(-4). Dynamic losses were 40J/cycle. A training effect was found in both dipoles. To investigate training effect an experiment was conducted with dipoles and small model magnets. Developed was the method of fast introduction of current above a critical value into the winding (electro-magnetic shock). Experiments with solenoids have shown, that placing a thin perlon film between winding layers sharply reduces training effect as in the case of training with ''electromagnet shock''. The SPD-3 and SPD-3' test results have shown, that similar superconducting dipole magnets with field homogeneity necessary for high-energy accelerators can be constructed