Development of strain measurement in superconducting magnet through fiber Bragg grating

Temperature and strain responses of fiber Bragg grating sensors were measured in cryogenic environment. With temperature from room temperature down to 77 K or 4.2 K, the temperature response was found to be relatively linear above 100 K, and the temperature sensitivity decreases with the decrease of temperature, and to approximately zero for temperature less than 50 K. Technologies were developed to eliminate the multi-peaks in strain experiment, so the strain response was measured at 77 K, and was found to be linear at constant temperatures.