Common coil magnet program at BNL

The goal of the common coil magnet R&D program at Brookhaven National Labor atory (BNL) is to develop a 12.5 T, 40 mm aperture dipole magnet using "Rea ct and Wind Technology'' with High Temperature Superconductors (HTS) playin g a major role, Due to its "conductor friendly'' nature, the common coil de sign is attractive for building high field 2-in-1 dipoles with brittle mate rials such as HTS and Nb,Sn. At the current rate of development, it is expe cted that a sufficient amount of HTS with the required performance would be available in a few years for building a short magnet. In the interim, the first generation dipoles will be built with Nb3Sn superconductor. They will use a "React and Wind" technology similar to that used in HTS and will pro duce a 12.5 T central field in a 40 mm aperture. The Nb3Sn coils and suppor t structure of this magnet will become a part of the next generation hybrid magnet with inner coils made of HTS, To develop various aspects of the tec hnology in a scientific and experimental manner, a 10-turn soil program has been started in parallel, The program allows a number of concepts to be ev aluated with ii rapid throughput in a cost-effective way, Three 10-turn Nb3 Sn coils have been built and one HTS coil is under construction. The initia l test results of this "React S: Wind" 10-turn coil program are presented, It is also shown that a common coil magnet design can produce a field quali ty that is as good as a conventional cosine theta design.