In-field strain and temperature measurements in a (RE)Ba2Cu3O7−x coil via Rayleigh-backscattering interrogated optical fibers. (1st June 2023)

• Record Type: Journal Article
• Authors: Scurti, F; Velez, C; Kelly, A; Ishmael, S; Schwartz, J
• Is Part Of: Smart materials and structures. Volume 32:Number 6(2023)
• Publication Date: 2023-06-01
• Subjects: Rayleigh-backscattering interrogated optical fibers -- distributed sensing -- quench detection -- superconducting magnets -- high temperature superconductors; Smart materials -- Periodicals; Strucural design -- Periodicals; 620.11
• DOI: 10.1088/1361-665X/acc7df
• Languages: English
• ISSNs: 0964-1726

Abstract

Abstract: (RE)Ba2 Cu3 O7-x (REBCO) conductors have overcome technical challenges related to manufacturing quality, length homogeneity, scale-up of piece-length, and joints. There is one remaining technical challenge, however, which is common to all high temperature superconductors and lies in effective detection of failure to prevent material degradation. An innovative technique based on optical fibers interrogated by Rayleigh backscattering has been shown to have advantages over voltage taps at detecting incipient faults. Prior work has experimentally demonstrated the technique in several implementation scenarios, including direct integration of optical fibers into superconducting conductors and cables to create a class of 'SMART' conductors and cables that are able to monitor their own health. In this paper, the magnet monitoring technique based on Rayleigh backscattering interrogated optical fibers has been experimentally studied in a model coil subject to external magnetic field, where different fiber integration methods are used to increase selectivity of the fiber sensor to temperature. Results show that the spectral shift displays different features during strain and thermal transients. The implications of the results in terms of potential and limitations of each sensor as well as strain-temperature decoupling are discussed.