Continuing results of systematic error in I/sub C/ testing

Critical current (I/sub C/) testing of the superconducting wire for the Superconducting Super Collider Laboratory (SSCL) is an important concern due to its significance in magnet variability. Established procedures to quantify measurement variability have been adapted to I/sub C/ measurements. To implement these ideas, a round robin experiment was developed and all vendor qualification program participants were required to become certified before the end of Phase II. The authors include updated results from all vendors, including foreign suppliers. The definition of each component of variability, test plan procedure quantifying each component, minimum SSCL certification requirements, current results, and future plans, are reported. Results show that all of the round robin participants have accuracy within the SSCL certified limit of +or-2% of the National Institute of Standards and Technology critical current Standard Reference Material value. Reproducibility results show that all of the test sites have less than a 2% uncertainty with the repeatability results falling between 1 and 3.5%. Cumulative uncertainty is determined to be between 1.5 and 5%.<>