2017 journal article

Self-monitoring 'SMART' (RE) Ba2Cu3O7-x conductor via integrated optical fibers

SUPERCONDUCTOR SCIENCE & TECHNOLOGY, 30(11).

By: F. Scurti n, S. Sathyamurthy*, M. Rupich * & J. Schwartz n

co-author countries: United States of America πŸ‡ΊπŸ‡Έ
author keywords: quench detection; optical fiber sensors; Rayleigh scattering; REBCO conductor; high temperature superconductor; magnet monitoring; distributed sensing
Source: Web Of Science
Added: August 6, 2018

A self-monitoring, SMART (RE)Ba2Cu3O7βˆ’x (REBCO) conductor has been created by integrating optical fibers into the solder fillet of the current REBCO conductor architecture. By interrogating the integrated optical fiber by Raleigh backscattering, a spectral shift signal as a function of time and position along the conductor is obtained. Due to the direct integration into the solder fillet, intimate, consistent contact between fiber and conductor is obtained, while the optical fiber is protected and does not take up any space in the magnet winding. Therefore, the SMART conductor enhances the benefits of the co-wound fiber approach and provides ultimate sensitivity and practicality. Several samples of SMART REBCO conductor have been manufactured and characterized. The strain self-sensing capabilities have been demonstrated as well as thermal perturbation detection and localization with 2.56 mm spatial resolution. Results show that a key feature of the SMART conductor concerns its sensitivity to thermal perturbation; unlike in the case of a coil with co-wound optical fiber, the SMART REBCO sensitivity increases as the temperature decreases. A series of quench measurements have been performed, both on straight samples and on a pancake coil, at temperatures as low as 14.6 K. Using the data collected by the SMART REBCO during quench experiments, the temporal evolution of the size of a normal zone and the instantaneous normal zone propagation velocity have been calculated.