Considerable stability increase of Nb3Sn multifilamentary wire internally doped with a large heat capacity substance (PrB6)

Two samples of Nb3Sn multifilamentary wires 0.82 mm diameter were prepared by the bronze method. One of the samples was internally doped with 7 vol% of PrB6, a large heat capacity substance (LHCS), while the other sample did not contain any LHCS and was used for comparison. The influence of LHCS internal doping on the stability toward short (∼1 ms) heat disturbances and critical currents in a transverse external magnetic field up to 3 T was investigated both experimentally and computationally. The average heat capacity for the doped sample in the temperature range 4-10 K was three times larger than for the undoped one. For the LHCS-doped sample its critical current was found to be slightly larger than for the comparison sample (6-8% depending on the external field), while its critical energies towards external heat disturbances were five times larger.