Speaker
Description
Superconducting magnets play a critical role in a wide range of applications, including their use as an enabling technology for fusion energy. However, ensuring their reliable operation requires robust monitoring techniques to prevent catastrophic magnet failure. Fiber optic sensors have emerged as a promising solution to address this technical gap, offering distributed, online strain and temperature measurements. Prior research has demonstrated that optical fibers can be successfully integrated into superconducting magnets, though further optimization is needed to maximize their performance and reliability.
This contribution presents recent progress at Penn State and collaborating institutions in the development of fiber optic sensing techniques for in-situ health monitoring of superconducting magnets. The work includes advancements in Rayleigh scattering-based Optical Frequency Domain Reflectometry (OFDR), particularly improvements in sensing length, measurement rate, and characterization of its response to vibrations and AC current operation. Additionally, new developments in Brillouin scattering-based Optical Time Domain Reflectometry (B-OTDR) for cryogenic applications are highlighted, with a focus on performance below 40 K. Results of a novel technique based on coherent-phase Optical Time Domain Reflectometry (cp-OTDR) are also presented, including its potential and current limitations in cryogenic environments. Further, we present the cryogenic characterization of a novel type of Fiber Bragg Grating (FBG) that can be inscribed in a wide range of optical fiber material compositions, enabling higher radiation tolerance for fusion reactor environments.
The effects of ionizing radiation on these sensing techniques are also investigated, since the optical fibers are to be integrated into systems exposed to ionizing radiation, such as particle accelerators and fusion reactors. Optical fibers Emphasis is placed on understanding how cryogenic irradiation influences sensor performance compared to room-temperature irradiation. Finally, we explore new concepts for integrating optical fibers into pancake coil configurations, including both insulated and non-insulated coil designs.
These advancements mark a step forward toward the deployment of fiber optic sensors as a tool for preventing failure of superconducting magnets operated in complex environments.
