Status of Nb-Ti CCT Magnet EU Programs for Hadron Therapy

The use of Canted Cosine Theta (CCT) magnets for accelerator applications has gained popularity due to their ease of manufacturing and assembly. In the context of two EU-Horizon2020-funded projects, HITRIplus and IFAST, the development of two 80 mm free bore and 4 T central field CCT dipoles for use in ion therapy (hadron therapy) is underway. In IFAST, a straight dipole CCT features a superimposed quadrupole component (combined function winding), while in HITRIplus a curved CCT (bending radius of 1.65 m) is wound as pure dipole. Both projects are based on a Cu/Nb-Ti multistrand rope as conductor. The article presents advancements in the engineering design of the magnets. A number of validation tests have been made to validate the choices made during the conceptual design. Characterization tests of the low losses rope, winding tests, splice tests, and impregnation tests will be described. The explored alternatives for the fabrication of the curved formers and the support structure are also discussed.