Fabrication and component testing results for a Nb3Sn dipole magnet

At present, the maximum field achieved in accelerator R ampersand D dipoles is slightly over 10T, with NbTi conductor at 1.8 K. Although Nb3Sn has the potential to achieve much higher fields, none of the previous dipoles constructed from Nb3Sn have broken the 10T barrier. We report here on the construction of a dipole with high current density Nb3Sn with a predicted short sample limit of 13T. A wind and react technique, followed by epoxy impregnation of the fiberglass insulated coils, was used. The problems identified with the use of Nb3SD in earlier dipole magnets were investigated in a series of supplemental tests. This includes measurement of the degradation of Jc with transverse strain, cabling degradation, joint resistance measurements, and epoxy strength tests. In addition, coff assembly techniques were developed to ensure that adequate prestress could be applied without damaging the reacted Nb3Sn cable. We report here the results of these tests and the construction status of this 50 mm bore dipole