A cryogenic white light absorption spectroscopy setup with <i>in situ</i> gamma irradiation and thermo-optical annealing for optical fiber radiation-induced attenuation characterization
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095209_1_5.0273589.pdf
Description
Published version
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9.3 MB
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Adobe PDF
Checksum (MD5)
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Author(s)
Legoupil, AYM
Kirby, R
Lamere, E
Christianson, R
Duke, O
Nguyen, AK
Short, MP
Date Issued
September 23, 2025
Journal
Review of Scientific Instruments
Publisher
AIP Publishing
Citation
A. Y. M. Legoupil, R. Kirby, E. Lamere, R. Christianson, O. Duke, A. K. Nguyen, M. P. Short; A cryogenic white light absorption spectroscopy setup with in situ gamma irradiation and thermo-optical annealing for optical fiber radiation-induced attenuation characterization. Rev. Sci. Instrum. 1 September 2025; 96 (9): 095209.
Version
Final published version
Abstract
Silica optical fiber sensors offer a fast, distributed measurement solution in various cryogenic and radiation environments, such as magnets for fusion power. Under these conditions, light-absorbing point defects limit lifetime via radiation-induced attenuation (RIA). To support RIA kinetics prediction, we present an in situ, broadband absorption spectroscopy setup combining gamma irradiation with liquid nitrogen cooling. The apparatus enables continuous monitoring of narrowband RIA levels and the use of secondary optical annealing light sources, alongside broadband spectrum measurements to characterize RIA defects through spectrum decomposition. Initial results confirm the inevitable photobleaching effect of the probe light source, which must be accounted for. In addition, we report RIA kinetics during cycles of gamma irradiation at 77 K and isochronal thermal annealing steps from liquid nitrogen to room temperature, showcasing the setup’s ability to replicate real fiber operation scenarios. These instruments form an ideal platform to further study the kinetics of RIA coupled with thermal and optical annealing.
MIT Department
Massachusetts Institute of Technology. Plasma Science and Fusion Center
Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
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Creative Commons Attribution-NonCommercial-NoDerivatives
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DOI of Published Version
https://doi.org/10.1063/5.0273589
