Strain and field scaling laws for internal Sn and bronze route Nb3Sn wires up to 21T

In this paper the field scaling law (Kramer) and the strain scaling laws (Ekin, ten Haken) are discussed and applied to various Bronze Route and Internal Sn Nb3Sn wires. In the first part, the field dependence (Kramer) for Nb3Sn industrial wires is treated, and measurements of critical current versus field up to 25T on an alloyed Bronze wire are presented and discussed. In the second part the strain dependence has been investigated, measuring the critical current density as a function of field and strain up to 21T (criterion 0.1 mu V/cm) for Bronze Route and Internal Sn Nb3Sn wires. The models of Ekin and ten Haken are used to quantify the different strain sensitivity that has been observed in the Bronze and in the Internal Sri wires, in the field region between 17 and 21 T. A composite model for explaining the higher strain sensitivity of J(c) of the Internal Sn wires respect to the Bronze is proposed, taking into account the individual Sri distributions in the A15 layer of both wire types.