Study of a Curved Superconducting Dipole for Carbon Ion Therapy Gantry

The Superconducting Ion Gantry project represents the contribution of INFN (Istituto Nazionale di Fisica Nucleare) to the European EuroSIG collaboration, which involves INFN, CNAO, CERN, and MedAustron, with the aim of developing new technologies based on superconducting magnets for hadron therapy. In particular, the project focuses on the study and development of the main magnets for a rotating gantry for carbon ions at 430 MeV/u, a key structure to improve the quality of cancer treatments by enabling irradiation from multiple angles, thus reducing the exposure of healthy tissues. The main objective of the project concerns the study of 45 degree bending dipoles in a cos-theta configuration, with the goal of realizing a 30 degree demonstrator featuring a bending radius of 1.65 m, an aperture of 80 mm, a magnetic field of 4 T, a ramp rate up to 0.4 T/s, and Nb-Ti coils cooled to cryogenic temperatures in a "liquid-free" mode. However, the challenges associated with winding strongly curved coils in a cos-theta configuration have driven the development of an alternative strategy based on block coil magnets, which offer a simpler geometry more suitable for fabricating curved dipoles with such small radii. In this context, an innovative winding technique has been developed, which involves the initial construction of the coil in a convex shape, subsequently deformed in a controlled manner with the aid of a mold to obtain the final concave form. Experimental tests have been conducted to demonstrate the feasibility of the technique and to study the mechanical behavior of the conductor throughout all stages of the procedure. At the same time, studies have been carried out for the electromagnetic design of curved dipoles in block coil configuration, capable of ensuring high field quality despite the distortions introduced by the curvature. The results obtained, both from an experimental and design perspective, are reported in this thesis work and demonstrate the validity of the proposed winding method, confirming the possibility of employing magnets in a block coil configuration as a competitive alternative to those in cos-theta configuration for hadron therapy applications.