Neutron degradation of UV enhanced optical fibers for fusion installation plasma diagnostics

The remote diagnostics of plasmas in fusion installations requires adequate connection links to transfer the measured signals in media subjected to high electromagnetic disturbances. We evaluated the neutron irradiation induced optical absorption in several commercially available optical fibers, as they were assessed for their possible use in fusion installations. Optical fiber samples were subjected to subsequent irradiation with fluences from 6 × 1011 to 6 × 1013 n/cm2. Significant radiation induced absorption was observed in the 220–260 nm spectral band, mainly for small core diameter optical fibers (200/220 μm), independent of the cladding material used.