First Winding Trial for the Superconducting Ion Gantry (SIG) Dipole Demonstrator Magnet

The Superconducting Ion Gantry (SIG) project aims to design, construct, and test a curved superconducting dipole demonstrator magnet for an ion gantry (up to a rigidity of 6.6 Tm). The main demonstrator magnet parameters are a dipolar field of 4 T generated into a toroidal aperture with an 80 mm diameter, 1.65 m curvature radius, and 30° angular sector. The project is inserted in the framework of the EuroSIG collaboration among CNAO, CERN, INFN, and MedAustron. Within this collaboration, the main goal of SIG is to perform a feasibility study of winding and assembling cos- θ coils with a small curvature radius. In addition, a parallel program at CERN is dedicated to the study of the indirect cooling problem through the construction of a straight thermal demonstrator magnet sharing the SIG cross-section. The basic idea behind these programs is to check whether the vast experience of the community on superconducting accelerator magnets design can lead to a breakthrough in the gantry magnets domain. This paper shows the main elements of the conceptual design of the SIG magnet and reports on the first winding trial performed at the LASA laboratory, in Milan, with a copper dummy cable. Moreover, possible solutions for the winding, curing, and impregnation of highly curved cos θ coils are discussed.