Toward standardization of critical current measurement method: VAMAS interlaboratory comparison. 1

This paper summarizes the results of the first critical current intercomparison implemented in the framework of VAMAS (Versailles Project on Materials and Standards) and discusses on the origins of data scatters reported by the participants. Three different Nb3Sn conductors were used and participants made measurements using their own techniques. As a result, variation coefficients for these samples were 8.0% to 29.9% at 12 T. A major source of these variations was found to be strain sensitivity of the Nb3Sn conductors. Effects of factors in the critical current measurement, such as magnetic field, temperature, current bypassing through mandrel, current transfer voltage, etc. were also examined on the basis of the results of the intercomparison. (author)