Progress in the development of Nb/sub 3/Sn conductors based on the "Powder in tube" method with finer filaments

Inspired by the successful operation of the 11 T Nb/sub 3/Sn experimental dipole magnet MSUT, a new large bore 10 T@4.5 K Nb/sub 3/Sn model dipole magnet is under development in The Netherlands. For application in this system, Shape Metal Innovation (SMI) has developed a new "Powder in Tube" type of Nb/sub 3/Sn conductor with an increased number of filaments. At a strand diameter of 0.9 mm, the diameter of the filaments after reaction for only 33 hours at 675/spl deg/C has been reduced to about 20 microns. The non-copper critical current density has been measured to be as high as 1890 A/mm/sup 2/ at 10 T@4.25 K.