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

Abstract

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(rm SiO-2) were carried out with an original setup that allows to investigate combined temperature and radiation effects on the sensors within a temperature range from 30circrm C to 250circrm 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 sim 5circrm C down to sim 0.5circrm 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

Radiation Characterization of Optical Frequency Domain Reflectometry Fiber-Based Distributed Sensors

“…These variations of temperature and strain coefficients induce an error on the two investigated parameters when the fibers are employed as sensors. This error is mostly related to the coating change when exposed to heating or to radiation [20]. Both release stress into the fiber and change the temperature and strain coefficients.…”

Effects of gamma radiation on perfluorinated polymer optical fibers

“…Fiber-based systems have been exploited for strain [2], temperature [3] or humidity [4] sensing in radiation environments. Various fiber sensing schemes are being investigated, including distributed Rayleigh [3,5], Raman [6] or Brillouin [7] scattering techniques and fiber Bragg gratings or interferometric sensors [8,9]. Moreover, number of optical fiberbased systems has been developed for direct radiation sensing and monitoring [10e12].…”

Real time monitoring of water level and temperature in storage fuel pools through optical fibre sensors

“…On the other hand, recent work from our group has shown that radiations at MGy dose levels do not affect the optical fibre Rayleigh signature at the basis of the OFDR technique. Indeed, temperature and strain coefficients remain unchanged, within the 5% error, up to 10 MGy for a large variety of standard fibre classes 16 and distributed temperature measurements (from −40 °C up to 250 °C) have been shown not to be influenced by radiations up to 1 MGy 17 , 18 . However, it has been shown that the potentialities of OFDR sensors are affected by Radiation Induced Attenuation (RIA) phenomenon 16 , which limits the sensing range of the fibre, while its packaging could modify the sensor calibration curves and consequently influences the distributed measurements 18 , 19 .…”