Development of a Fast Ramped Superconducting Dipole Magnet
by Hans Müller (GSI) and Pasquale Fabbricatore (INFN)
One curved dipole coil of the CRISP project after curing and impregnation of the coil ends.
Image credit: Pasquale Fabbricatore (INFN)
Fast ramped magnets are an essential component of heavy-ion synchrotrons. Future developments ask for higher rigidity of the beams leading to stronger magnetic fields of the magnets and therefore to superconductivity. A superconducting fast ramped dipole magnet is now being developed in frame of the CRISP project.
The magnet is based on the DISCORAP dipole built and tested by INFN as a prototype for the planned SIS300 synchrotron of FAIR in Darmstadt, Germany. The magnet has a main field of 4.5 T and the ramp rate is 1 T/s, which is orders of magnitude higher than any used currently. Its length is about 5 m and the inner diameter of the coil is 100 mm. The magnet is of so-called cos(theta) design, where the shape of the coil determines the field. This requires a high precision in the manufacturing of such a coil and the surrounding collar, which takes the magnetic forces. To increase the acceptance the magnet is wound curved making manufacturing difficult. Another challenge to be addressed is to minimize the AC-losses of the conductor due to ramping. For this, dedicated new superconductors with small NbTi filaments of only about 3 µm diameter had been developed. Another issue to be considered is fatigue, which requires high strength austenitic steel for the coil support. The collared coil being built now is a first step towards a complete magnet and establishes technologies to be used for further developments in the field of fast ramped superconducting magnets.
