Thermomechanical design of a ramped, conduction cooled, curved CCT superconducting magnet

Hadron therapy is a medical technique that uses hadronic particles, such as carbon ions and protons, to treat tumours. Among these, carbon ions are particularly effective due to their high and localised energy deposition. However, their application is limited by the large size and high cost of the required facilities. A key component of the facilities is the gantry, a rotating device that delivers the particle beam from multiple angles to the patient, significantly enhancing treatment effectiveness. A new European gantry design aims to reduce both the weight and cost for carbon ion delivery, making hadron therapy more accessible. In such systems, magnets are used to steer and guide the particles along their path to the patient. Several magnet layouts are under study for this application, one of which is the Canted-Cosine-Theta (CCT) under development at CERN and INFN in the context of the European programs H2020-HITRI plus and H2020-I.FAST, led by INFN with CERN and other partners. In this layout, the NbTi coil is composed of two tilted solenoids supported by a mandrel called former. This paper presents the thermomechanical design of the CCT magnet, addressing the challenges posed by its unique combination of conduction cooling, moderate ramp rate and strong curvature. The paper shows the cooling system design, the mechanical structure, the thermomechanical analyses and the construction process developed to integrate thermal and mechanical design. This work represents the first step towards assessing magnet feasibility, testing and construction. • First complete thermomechanical design of a CCT magnet with unprecedented features. • Successful integration of strong curvature, moderate ramping and conduction cooling. • First-time presentation of the cooling system, mechanical structure and fabrication process for this class of magnet. • First step towards feasibility demonstration.