Evaluation of superconducting magnet technology to improve the energy efficiency of a high intensity muon beam facility

Abstract

The High-Intensity Proton Accelerator (HIPA) facility at the Paul Scherrer Institute (PSI) is undergoing significant upgrades to support advanced experiments on charged lepton flavor violation. To achieve this, one of the existing target stations and its two connected beamlines will be dismantled and rebuilt as part of the High-Intensity Muon Beam (HIMB) project. The new MuH2 and MuH3 beamlines will incorporate 15 large aperture solenoids and five dipoles designed for muon beam transport to handle a large phase-space beam. The transport beamline components are based on standard resistive magnets, which suffer from high power consumption. This study explores the integration of superconducting magnet technology as a viable alternative to reduce power consumption and enhance the overall performance of the HIMB facility. A simulation model incorporating radiation-induced thermal loads was developed using COMSOL Multiphysics, enabling realistic assessments of magnet performance. The study revealed that while low-temperature superconducting solenoids, which are based on Niobium-Titanium (NbTi), are effective in most settings, the extreme radiation heat load close to the target requires the use of a High-Temperature Superconductor (HTS) like Yttrium Barium Copper Oxide (YBCO) to ensure thermal stability and resilience. This led to successfully modeling an HTS YBCO solenoid, demonstrating its superior performance in high-radiation scenarios. To further advance the feasibility of superconducting technology, the dissertation investigated layer winding techniques for YBCO tapes to overcome the challenges associated with traditional winding methods. Practical testing of a layer-wound YBCO magnet prototype at PSI confirmed no degradation in critical current, validating this method for future Research and Development (R&D) activities, particularly for the HTS demonstrator for HIMB radiation damage testing. Economic and environmental evaluations underscored the substantial benefits of adopting superconducting solenoids over resistive magnets, highlighting significant energy savings and reductions in Carbon Dioxide (CO2) emissions despite higher initial costs. Results of this study have shown that, over 15 years, operational savings make superconducting technology a financially and environmentally viable alternative. Consequently, the PSI directorate endorsed implementing one superconducting solenoid for HIMB, marking a significant advancement in PSI’s commitment to sustainable, energy-efficient accelerator technologies and setting a benchmark for future integrations within the HIMB facility and beyond.