Design and fabrication of a stress-managed Nb3Sn wind and react dipole

Abstract

A new approach to high-field dipole design is being developed at Texas A&M University. The goal of the development is to facilitate the use of high-field conductors (Nb3 and Bi-2212) and to manage Lorentz stress and magnetization so that field strength can be extended to 25 Tesla. The new design incorporates several innovations, including stress management, flux plate suppression of multipoles, and bladder preload. A series of model dipoles is being built and tested to validate and optimize each of these innovations. The second such model dipole, TAMU2, has been completed and was recently tested at Lawrence Berkeley National Laboritory. It achieved 93% of cable short sample limit on the first quench and every subsequent quench and did not suffer from any detectable training. This level of performance corrisponds to currents over 8800 A and a measureable field strength of 4.6 T. Ramp rate studies indicate robust behavior under fast ramping; we interpret this to be a beneficial result of the block coil geometry and the chrome-plated conductor.