Design, Fabrication and Testing of Nb3Sn Shell Type Coils in Mirror Magnet Configuration

摘要

Fermilab is involved in the development of Nb3Sn magnets for future hadron colliders. One of the magnet design options is based on cosine-theta coils and the wind-and-react approach. Three short dipole models of this type were fabricated and tested revealing serious problems in magnet quench performance. To effectively address these issues, coil tests were continued in a mirror magnet configuration, where one coil was replaced with a half-cylinder of low carbon steel (the magnetic mirror) inside the magnet mechanical structure. This approach has reduced the fabrication cost and time as well as improved the coil instrumentation. The paper summarizes the magnetic and mechanical design of mirror magnet configuration along with fabrication details.