Consolidated 2D Mechanical Design and Preliminary 3D Design Phase of the Superconducting Ion Gantry (SIG) Dipole for Hadrontherapy

Abstract

In ion therapy, gantries play a crucial role in minimizing damage to healthy tissue and enabling treatment from diverse angles. The introduction of superconducting magnets results in a substantial reduction in the overall weight and the power required to operate of these otherwise huge structures. The Superconducting Ion Gantry (SIG) project represents the contribution of INFN (Istituto Nazionale di Fisica Nucleare) to the EuroSIG collaboration, which includes CERN, CNAO (Centro Nazionale di Adroterapia Oncologica), and MedAustron. The primary goal is to design, manufacture, and test a demonstrator for a curved superconducting dipole with costheta-type NbTi coils for a 430 MeV/u carbon ion gantry. The magnet is designed with a 1.65 m radius of curvature and an 80 mm aperture, aiming to generate a magnetic field up to 4 T, with a ramp rate of about 0.4 T/s, without the option of utilizing a direct cooling system. The winding, assembly, and testing of the magnet will be carried out in Milan, at LASA (Laboratorio Acceleratori e Superconduttività Applicata). However, the available press is insufficient in size compared to the dimensions of the magnet. To overcome this limitation, an alternative method has been devised for the assembly of the iron yoke, relying on a steel system of clamps and vertical tie rods. These clamps have the purpose of securely fastening the two yoke halves together. This study presents the final design of the mechanical structure cross-section, derived through finite element analyses, highlighting the optimization of mechanical contacts between components while adhering to structural limits. Additionally, a preliminary 3D design based on this optimized cross-section is introduced.