Radiation Hardened Optical Frequency Domain Reflectometry Distributed Temperature Fiber-Based Sensors

We study the performance of Optical Frequency Domain Reflectometry (OFDR) distributed temperature sensors using radiation resistant single-mode optical fibers. In situ experiments under 10 keV X-rays exposure up to 1 MGy( SiO₂) were carried out with an original setup that allows to investigate combined temperature and radiation effects on the sensors within a temperature range from 30^°C to 250^°C. Obtained results demonstrate that optical fiber sensors based on Rayleigh technique are almost unaffected by radiation up to the explored doses. We show that a pre-thermal treatment stabilize the sensor performance increasing the accuracy on temperature measurement from ~ 5^°C down to ~ 0.5^°C by reducing the packaging-related errors (such as ones related to coating modification) that could be introduced during the measurement. These results are very promising for the future integration of Rayleigh based sensors in nuclear facilities.