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High Critical-Current Measurements in Liquid and Gaseous Helium

  • L. F. Goodrich
  • L. T. Medina
  • T. C. Stauffer
Part of the Advances in Cryogenic Engineering book series (ACRE, volume 44)

Abstract

We compared variable-temperature critical-current, Ic(T), measurements up to 200 A on samples immersed in liquid helium to those on samples in flowing helium gas. Multifilamentary Nb-Ti and Nb3Sn samples were used in this study. Ic(T) measurements above 5 K are difficult because these measurements need to be done in helium gas and the heat generated during the measurement and conducted down high-current leads can raise the sample temperature significantly. This creates a large uncertainty and perhaps a sample dependent bias in the sample temperature that occurs even if the measurements are made meticulously. Ic(T) measurements at a constant magnetic field are needed to determine the temperature margin of magnet applications and performance data for cryogen-free applications. The comparison of Ic(T) data in liquid helium to data in gaseous helium, over the temperature range of 4 to 5 K, allows for the inference of sample temperature uncertainty and biases. Agreement to within 30 mK was obtained.

Keywords

Critical Current Density Settling Time Pulse Method Liquid Data Current Contact 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer Science+Business Media New York 1998

Authors and Affiliations

  • L. F. Goodrich
    • 1
  • L. T. Medina
    • 1
  • T. C. Stauffer
    • 1
  1. 1.National Institute of Standards and TechnologyBoulderUSA

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