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Comparative Study of Pulsed γ-Ray and 7-Ray Radiation-Induced Effects in Pure-Silica-Core Optical Fibers.
- Source :
- IEEE Transactions on Nuclear Science; Aug2006 Part 1 Of 2, Vol. 53 Issue 4, p1756-1763, 8p, 1 Chart, 8 Graphs
- Publication Year :
- 2006
-
Abstract
- We have investigated the variation of the optical absorption induced by pulsed (dose rate > 10<superscript>8</superscript> rad/s) and continuous (<50 rad/s) γ-ray exposures in pure-silica-core optical fibers. Tested multimode waveguides, designed with well-defined concentrations of hydroxyl groups and chlorine impurity, are possible candidates for integration in the plasma diagnostics of LMJ and ITER facilities. We evaluated their radiation-tolerance to low dose levels (<5 × 10<superscript>4</superscript> rad) in the visible and near-infrared parts of the spectrum. We measure the time dependent changes (10<superscript>-9</superscript>–10<superscript>-1</superscript> s) of the radiation-induced attenuation (RIA) at fixed wavelengths and we complete these measurements with a spectral (450–1100 nm) analysis of these losses in the time range from 10<superscript>-2</superscript> to 10³ s. We compared the responses obtained under transient exposures with measurements done at same dose levels (5 × 10³ rad) with lower dose rate (<10² rad/s). We showed that the radiation-induced changes are strongly dose rate dependent for this kind of optical fibers. Depending on the hydroxyl group concentration in the silica-glass, different point defects are shown to alter the fiber transmission after both irradiation types. The self-trapped holes play a particular role in the transient responses of optical fibers whereas non-bridging oxygen hole centers are mainly responsible for γ-ray radiation-induced losses. The consequences of these different behaviors for the integration of optical fibers in the LMJ are discussed. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00189499
- Volume :
- 53
- Issue :
- 4
- Database :
- Complementary Index
- Journal :
- IEEE Transactions on Nuclear Science
- Publication Type :
- Academic Journal
- Accession number :
- 22324641
- Full Text :
- https://doi.org/10.1109/TNS.2006.877852