A.C. energy losses of Nb-Ti multifilamentary superconductors for the magnets of the nuclotron

The performances of the installation used to measure a.c. energy losses of short superconducting samples in an external pulsed magnetic field are given. The calorimetric method at 4.2 K is used. The measurable range of losses is from 10 up to 1000 mW. The results of loss measurements of superconducting wires and tubular cables with a various diameter of superconducting filaments and twist length are presented. The experimental values of hysteresis and eddy current losses are compared with the calculated ones. The influence of the Nb barrier and solid-state diffusion on the loss values is investigated.