Multifilament Nb3Sn conductors: Progress and prospects

Multifilament Nb3Sn conductors are now at the stage where several coils have been constructed and various types of material are available commercially from several suppliers. Even so, some questions remain with regard to the reliable use of this material, particularly in large-scale systems. The initial portion of this paper covers the main features of past work as they relate to the present situation. In the latter part, those areas where major uncertainties remain are described along with current projected work in these areas.