Inspired by the successful operation of the 11 T Nb3Sn experimental dipole magnet MSUT, a new large bore 10 T@4.5 K Nb3 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 Nb3Sn 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°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 2 at 10 T@4.25 K.
Lindenhovius, J. H., Hornsveld, E. M., den Ouden, A., Wessel, W. A. J., & ten Kate, H. H. J. (1999). Progress in the development of Nb3Sn conductors based on the "Powder in tube" method with finer filaments. IEEE transactions on applied superconductivity, 9(2), 1451-1454. https://doi.org/10.1109/77.784664