Critical current in NbTi wires irradiated by neutrons at 20 K

Abstract

In the present paper the results of experimental investigations of NbTi superconducting wires are given with two different treatments: cold-deformed (CD), intermediate thermal treatment (ITT) and also NbTi multiwire of factory treatment. The influence of neutron irradiation on the critical current I c dependence on magnetic field was studied in the cryochannel of nuclear reactor. Integral neutron fluence of 3 × 10 18 cm −2 in one core wires increases I c for CD samples, but doesn't change for ITT samples. Integral neutron fluence of 1.6 × 10 18 cm −2 leads to substantial I c-degradation for multiwire, its value undergoes twofold reduction, that is due to the decrease of the working cross-section of the optimized superconducting buses at the expense of its presurface layer `spoiling' as a result of enrichment by foreign atoms from the matrix of stabilizer.