Radiation tolerant fiber Bragg gratings for high temperature monitoring at MGy dose levels
- Authors: Morana, A; Girard, S; Marin, E; Marcandella, C; Paillet, P; Périsse, J; Macé, JR; Boukenter, A; Cannas, M; Ouerdane, Y
- Publication year: 2014
- Type: Articolo in rivista (Articolo in rivista)
- OA Link: http://hdl.handle.net/10447/97146
Abstract
We report a method for fabricating fiber Bragg gratings (FBG) resistant to very severe environments mixing high radiation doses (up to 3 MGy) and high temperatures (up to 230°C). Such FBGs have been written in two types of radiation resistant optical fibers (pure-silica and fluorine-doped cores) by exposures to a 800 nm femtosecond IR laser at power exceeding 500 mWand then subjected to a thermal annealing treatment of 15 min at 750°C. Under radiation, our study reveals that the radiation induced Bragg wavelength shift (BWS) at a 3 MGy dose is strongly reduced compared to responses of FBGs written with nonoptimized conditions. The BWS remains lower than 10 pm for temperatures of irradiation ranging from 25°C to 230°C without noticeable decrease of the FBG peak amplitude. For an applicative point of view, this radiation induced BWS corresponds to an additional error on the temperature measurements lower than 1.5°C, opening the way to the development of radiation-tolerant multi-point temperature sensors for nuclear industry.