Influence of Hydroxyl Content and Preirradiation on the Radioluminescence of Pure‐Silica‐Core Optical Fibers

This study investigates how the X‐ray radiation‐induced luminescence (RIL) of multimode pure‐silica‐core (MM‐PSC) optical fibers is influenced by their hydroxyl (OH) content and by a preirradiation treatment up to 300 kGy(SiO 2 ). To achieve this objective, three MM‐PSC fibers with low‐, medium‐, and high‐OH contents were evaluated for their RIL response before and after a 300 kGy preirradiation. The high‐OH fiber exhibits the lowest RIL level but with excellent linearity as a function of the dose rate and a good stability over dose. Consequently, this fiber, having its RIL spectrum dominated by the nonbridging oxygen hole centers (NBOHCs) contribution, appears as a suitable dosimetry solution for high dose rate environments. The medium‐OH fiber showed the larger RIL at low doses and after preirradiation, its RIL is dominated by the contribution of silica oxygen‐deficient centers (SiODC(II)) and NBOHCs. For the low‐OH fiber, the same two defects are responsible for its RIL, which also increases with cumulated dose. These results highlight the critical role of OH content and preirradiation on RIL characteristics, with implications for the design of radiation‐hardened fiber‐based dosimeters.