Low Power Consumption Superconducting Solenoids for the PSI High-Intensity Muon Beams Project - A Design Study

The next generation of experiments on charged lepton flavor violation demands higher muon rates. To achieve this, one of the existing target stations at the Paul Scherrer Institute's high-intensity proton accelerator, along with its two connected beamlines, will be dismantled and rebuilt as part of the High Intensity Muon Beams (HIMB) project, under the Swiss Roadmap for Research Infrastructures initiative, IMPACT. The new MuH2 and MuH3 beamlines will rely on 15 large-aperture solenoids and 5 dipoles for muon beam transport, designed to handle a large phase-space beam. Our estimates of the absorbed dose levels indicate that five transport solenoids and two dipoles must be radiation-resistant, requiring the use of mineral-insulated cables, whilst the other magnets can utilize epoxy-impregnated coils. Currently, the design of transport beamline components is based on standard resistive magnets, which suffer from high power consumption. This study aims to explore an alternative using Nb-Ti superconducting coils to reduce power consumption. The paper focuses on the design study of transport solenoids and includes a thermo-economic analysis, considering radiation exposure at three positions relative to the target.