Future superconducting magnets with “sensing nerves”: Distributed fiber optic sensing for quench detection and thermomechanical integrity

Optical Frequency Domain Reflectometry (OFDR), based on Rayleigh scattering, offers an innovative diagnostic approach for superconducting magnets. In addition to its high spatial resolution, electromagnetic immunity, and distributed sensing capability, OFDR allows continuous and quantitative mapping of thermomechanical states throughout the magnet’s lifecycle—from initial winding pre-stress and cooldown to excitation and quench. For critical performance monitoring, particularly in tracking the combined strain–temperature behavior under cryogenic and high-field conditions, OFDR provides a level of accuracy and spatial detail that is difficult to match with existing sensing methods. Although engineering challenges remain, including cryogenic calibration, strain transfer, signal decoupling, and system integration, most can be resolved as the technology matures. Looking ahead, OFDR is poised to become a core technology for next-generation “smart” superconducting structures, redefining diagnostic strategies in high-energy physics and fusion magnet systems.