The Niobium-Tin project

One of the goals that is pursued with the construction of superconductive undulators is to achieve comparatively high magnetic fields (1-2 T) on the axis of undulators with a short period (~10 mm). This leads to the generation of synchrotron radiation with a very short wavelength. The wavelength of the radiation emitted in an undulator is given by (formula).

The figure of merit for increasing the on axis magnetic field strength (for a given period length) in superconductive undulators is the achievable current density in the superconductor. A common conductor material for superconductive undulators is NbTi. An alternative is to use Nb₃Sn, which can possibly achieve a critical current density twice as large as that of NbTi. However, Nb₃Sn is quite brittle and its production and handling are more demanding than that of NbTi. Moreover the processing of the Nb₃Sn wire has to be optimized for the range of magnetic field strength in which the wire is to be used. This R&D and optimization is the focus of the Nb₃Sn project.