In this work, we demonstrate optomechanical measurements of radiation induced alterations of the acoustic velocity in a fluoroacrylate polymer coating of a silica optical fiber. The optomechanical measurement is based on forward Brillouin scattering initiated in the fiber core which stimulates acoustic waves that reach the fiber coating. The measurement may serve as an additional metric to quantify the dose of ionizing radiation to which the fiber was exposed. We have demonstrated that the stiffness of the coating increases following gamma irradiation, as measured by the time of flight of radial acoustic waves through the coating. The measurement was performed on few meters long fiber, but can be extended to a spatially distributed analysis in longer fibers. The tests showed a linear dependence of the acoustic time-of flight on the overall dosage of gamma irradiation. The time of flight decreased by as much as 15% following exposure to 180 Mrad from a 60Co source. In a follow-up study, we found that the stiffness of the previously exposed fiber coatings continued to slowly increase over months, after extraction from the radiation field. These results reveal the vulnerability of the specific coating to ionizing radiation and the potential complexities involved with dosimetry.
|Title of host publication||Micro-Structured and Specialty Optical Fibres VII|
|Editors||Kyriacos Kalli, Pavel Peterka, Christian-Alexander Bunge|
|State||Published - 2022|
|Event||Micro-Structured and Specialty Optical Fibres VII 2022 - Virtual, Online|
Duration: 9 May 2022 → 20 May 2022
|Name||Proceedings of SPIE - The International Society for Optical Engineering|
|Conference||Micro-Structured and Specialty Optical Fibres VII 2022|
|Period||9/05/22 → 20/05/22|
Bibliographical notePublisher Copyright:
© 2022 SPIE.
- fiber optic sensors
- fiber optics
- forward Brillouin scattering
- radiation dosimetry
- structural health monitoring