With the LHC the limits of NbTi superconductors have been reached. For
future accelerators (VLHC, muon collider) not only the accelerator
dimensions but also the main dipole field must be increased, preferably
in the range of 11-14 T. With two experimental dipole magnets employing
Nb3Sn superconductors it has already been demonstrated that these expectations appear to be realistic:
- 11.3 T at 4.4 K, dipole magnet MSUT (Univ. of Twente, STW, NIKHEF, CERN)
- 13.3 T at 1.8 K, dipole magnet D-20 (LBNL,USA).
In this talk the opportunities and challenges with respect to higher fields and current densities in accelerator magnets employing Nb3Sn
superconductors will be discussed. The development and test results of
the dipole magnet MSUT illustrates the technological issues and the need for dedicated R&D in order to obtain Nb3Sn magnets within accelerator specifications. Finally, current developments in the field of magnets and conductors will show that actual implementation of Nb3Sn magnets in accelerators can be expected within a few years.
