Mu2e Transport Solenoid Prototype Design and Manufacturing

Abstract

The Mu2e Transport Solenoid consists of fifty-two coils arranged in twenty-seven coil modules that form the S- shaped cold mass. Each coil is wound from Al-stabilized NbTi superconductor. The coils are supported by an external structural aluminum shell machined from a forged billet. Most of the coil modules house two coils with the axis of each coil oriented at an angle of approximately five degrees with respect to each other. The coils are indirectly cooled with LHe circulating in tubes welded on the shell. In order to enhance the cooling capacity, pure aluminum sheets connect the inner bore of the coils to the cooling tubes. The coils are placed inside the shell by the means of a shrink fit procedure. A full-size prototype, with all the features of the full assembly, was successfully manufactured in a collaboration between INFN-Genoa and Fermilab. In order to ensure an optimal mechanical pre-stress at the coil-shell interface, the coils are inserted into the shell through a shrink fitting process. We present the details of the prototype with the design choices as validated by the structural analysis. The fabrication steps are described as well.  Index Terms—Superconducting Magnets, Solenoids, Accelerator Magnets