Critical current measurements of Nb3Sn superconductors: NBS contribution to the VAMAS interlaboratory comparison

✍ Scribed by L.F. Goodrich; S.L. Bray

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 913 KB
• Volume: 29
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/0011-2275(89)90135-5

✦ Synopsis

Critical current measurements on several Nb3Sn superconductors were made as part of an interlaboratory comparison (round robin). These measurements were made in conjunction with twenty-four laboratories from the European Economic Community, Japan and the USA as part of the Versailles Agreement on Advanced Materials and Standards (VAMAS). The results of the NBS measurements, including the effect of sample mounting techniques on the measured critical current, are given. A systematic study of the effect of measurement mandrel (tubular sample-holder made from G10 fibreglass-epoxy composite) geometry revealed that a seemingly small change in that geometry can result in a 40% change in the measured critical current at a magnetic field of 12T. Specifically, the radial thermal contraction of the measurement mandrel depends on its wall thickness and, thus, so does the conductor pre~train (at 4 K) and, ultimately, the measured critical current. Techniques for reducing variation in the measured critical current are suggested.