VAMAS INTERCOMPARISON OF CRITICAL-CURRENT MEASUREMENTS ON NB3SN SUPERCONDUCTORS - A SUMMARY REPORT

This paper is a summary of an international collaboration endorsed by VAMAS to study problems associated with critical current measurements in Nb3Sn superconductors and provide guidelines for a standard measure ment. Two series of critical current measurements were implemented. In the first series, three different sample conductors were used and par ticipants made measurements using their own techniques. As a result, c oefficients of variation for these samples at 12 T turned out to be 8- 29.9%. A major source of these variations was attributed to strain sen sitivity of the Nb3Sn conductors. Thus, the second series of measureme nts were done on one sample conductor and under specified measurement conditions, particularly in terms of specimen strain. The coefficient of variation decreased to 2.2%, which is regarded as a reasonable base for future establishment of an international standard measurement met hod.