Fast Ramped Superferric Prototypes and Conclusions for the Final Design of the SIS 100 Main Magnets

The 100 Tm synchrotron SIS 100 is the core component of the Facility of Antiproton and Ion Research (FAIR). An intensive R&D allowed reducing the AC losses considerably as well as improving the field quality. High priority was also given to the investigation of the mechanical stability of the superconducting coil to guarantee a long term life time of at least 20 years with more than 2middot10⁸ operation cycles and to position the cable windings precisely. Prototype magnets were built last year with the first dipole magnet completed by Babcock Noell GmbH and currently being under preparation for intensive testing. After a brief description of the main R&D results the key features of three full scale dipoles and a quadrupole prototype are given as well as the expected heat load at 4 K for the 3 m long dipoles for the most important operation modes requested for the SIS100 accelerator. During prototyping additional, more intensive operation cycles were requested by beam dynamics and more cooling power by the vacuum requirements. The consequences for the cooling stability of the dipoles were estimated and preliminary tested on a hydraulic equivalent magnet system and will be verified by the upcoming measurements of the full size models. Necessary modifications for the series production are discussed and the actual chosen SIS100 dipole design fulfilling also the additional operation requirements is outlined.