Study of Fibre Bragg Grating samples exposed to High Fast-Neutron Fluences

Research output: Contribution to journalArticle

Authors

  • Andrei Goussarov
  • Guy Cheymol
  • Laurent Remy
  • D. Kinet
  • P. Mégret
  • G. Laffont
  • T. Blanchet
  • A. Morana
  • E. Marin
  • S. Girard

Institutes & Expert groups

  • CEA Saclay - Commissariat à l'énergie atomique
  • UMons - University of Mons-Hainaut
  • Université de Saint-Etienne - Laboratoire Hubert Curien

Documents & links

DOI

Abstract

Fibre Bragg Grating (FBG) sensors are expected to provide valuable data in extreme radiation environments associated with nuclear research reactors. However, when the fast neutron fluence reaches 1018 to 1019 n/cm², the radiation induced changes in the material density and refractive index may drastically bias the measurements. The present study evaluates the radiation effect on the FBG performances by comparing their properties before and after their exposure to fast neutron fluences exceeding 1019 n/cm² (E > 1 MeV). We studied responses of FBGs manufactured by three different laboratories in the same single-mode optical fibre but using different inscription conditions. The Bragg wavelength and the reflectivity were measured before and after irradiation thanks to a dedicated mounting. For nearly all FBGs, the Bragg peak remains visible after the irradiation while the radiation-induced Bragg wavelength shifts (RI-BWS) vary from a few pm (equivalent temperature error <1°C) to nearly 1 nm (~100°C error) depending of the FBG inscription conditions. Such high RI-BWSs can be explained by the huge refractive-index variation and compaction observed for bare fibre samples through other experimental techniques. Our results show that by using specific hardening techniques the FBG-based temperature measurements in a nuclear research reactor experiment may become feasible.

Details

Original languageEnglish
Article number102
Pages (from-to)1-8
Number of pages8
JournalIEEE transactions on nuclear science
Volume65
Issue number9
DOIs
StatePublished - 21 Feb 2018

Keywords

  • Fibre Bragg grating, optical fibre sensors, radiation effect, optical fibres, neutron, gamma, compaction

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