DESIGN AND STUDY OF THE IRIS 10 T ENERGY SAVING DIPOLE MAGNET FOR ACCELERATORS: ESMA

The research and development of new superconducting materials is progressively refining the manufacturing of a new class of conductors: REBCO tapes. Although REBCO was discovered in 1987, tape manufacturing suitable for magnet windings has only recently been optimized. REBCO tapes belong to the class of High Temperature Superconductors (HTS), a class of materials which remain superconducting at temperatures higher than liquid nitrogen, in contrast to classical Low Temperature Superconductors (LTS) that require liquid helium refrigeration. This capability has the potential to transform superconducting magnet technology by enabling a wide range of applications in medical, energy, and societal domains beyond particle accelerators. The possibility of operating at higher temperatures simplifies infrastructure and improves thermal efficiency, yielding substantial energy savings and making the technology more sustainable. However, manufacturing challenges as sudden localized performance drops and unforeseen defects occurrences as well as the early stage of understanding of these conductors make a reliable application a challenging quest.\\ The objective of this thesis is to set an initial milestone toward a new generation of superconducting dipole magnets by exploiting REBCO tapes to realize a complete HTS technological demonstrator. Within the IRIS project, funded by the NextGeneration EU (PNRR), the Energy Saving Magnet for Accelerators (ESMA) was conceived to reach a peak central field of 10 T and to operate cryogen-free at 20 K, thus yielding more than competitive conductor performance with respect to classical LTS while delivering an estimated energy saving relative to operation at 4.2 K of roughly a factor five. The project is a collaboration with industry, ASG Superconductors, for magnet construction and co-design.\\ This thesis addresses the challenges of designing an HTS dipole magnet, beginning with the electromagnetic configuration while accounting for the mechanical constraints of using tape rather than round wire or cable. The procured tape was extensively characterized through electrical and mechanical measurements to provide insight for the design phase and to build in-house expertise at the LASA laboratory. After completing the integrated electromagnetic, mechanical, and thermal design, the operation of the magnet was studied with dedicated analyses aimed at optimizing charging procedures while respecting thermal limits, critical since ESMA will also serve as a variable field user facility at INFN Genova. Quench dynamics and AC losses were investigated in collaboration with Little Beast Engineering, to prepare an intervention or mitigation strategy in case of quench and to confirm a reliable operation. Lastly, an experimental campaign was carried out to design, manufacture, and test small HTS windings to validate handling and winding procedures, to study tape behavior under realistic processing, and to confirm the design assumptions used for ESMA.