Radiation-induced attenuation (RIA) at a wavelength of $\lambda = 1.55\,\,\mu \text{m}$ as well as the RIA spectra were investigated in optical fibers during and after irradiation at the IVG.1M nuclear reactor (Republic of Kazakhstan). The fibers studied were single mode at $\lambda = 1.55\,\,\mu \text{m}$ , had an undoped silica core and an-F-doped silica cladding [pure-silica fibers (PSFs)], and were provided by different manufacturers. In addition to five PSFs, a single-mode revolver hollow-core fiber was also studied. The PSFs had different coating materials: polyimide, copper, or aluminum. All fibers were exposed to three runs of reactor irradiation at enhanced temperature (155–355 °C) so that by the end of the third run, the fast-neutron fluence amounted to $\Phi = 4.46\cdot 10^{17}$ n/cm² and $\gamma $ -dose to $D = 2.91\cdot 10^{7}$ Gy. The total induced loss at $\lambda = 1.55\,\,\mu \text{m}$ was found to be composed of 1) RIA, 2) bending loss (BL), caused by thermal expansion of the copper cylinder the PSFs were wound on, and 3) thermo-induced microbending loss (ML) in Cu-coated PSFs. At the end of the irradiation campaign, the net RIA in PSFs proved to lie in the interval of 0.12–0.16 dB/m, which appears to be admissible to intrareactor transport fibers. It was confirmed that long-wavelength RIA tail is the only RIA origin at $\lambda = 1.55\,\,\mu \text{m}$ in PSFs in such strong radiation fields. The hollow-core fiber was found to feature zeroth RIA throughout the campaign.

中文翻译：

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单模光纤在IVG.1M核反应堆辐照下λ=1.55 μm的辐射电阻

波长范围内的辐射诱导衰减 (RIA) $\lambda = 1.55\,\,\mu \text{m}$ 以及在 IVG.1M 核反应堆（哈萨克斯坦共和国）辐照期间和之后对光纤中的 RIA 光谱进行了研究。所研究的光纤是单模在 $\lambda = 1.55\,\,\mu \text{m}$ ，具有未掺杂的二氧化硅纤芯和掺杂 F 的二氧化硅包层 [纯二氧化硅光纤 (PSF)]，由不同的制造商提供。除了五个 PSF 之外，还研究了单模左轮手枪空心光纤。PSF 具有不同的涂层材料：聚酰亚胺、铜或铝。所有的纤维都在高温（155-355°C）下进行了三轮反应器辐照，因此在第三轮结束时，快中子注量达到 $\Phi = 4.46\cdot 10^{17}$ n/cm ²和 $\伽马$ - 剂量 $D = 2.91\cdot 10^{7}$ 吉。总诱导损失在 $\lambda = 1.55\,\,\mu \text{m}$ 发现由 1) RIA，2) 弯曲损耗 (BL) 组成，由缠绕 PSF 的铜圆柱的热膨胀引起，以及 3) 镀铜 PSF 中的热诱导微弯曲损耗 (ML)。在辐照活动结束时，PSF 中的净 RIA 被证明位于 0.12-0.16 dB/m 的区间内，这似乎是反应器内传输光纤可接受的。经证实，长波长 RIA 尾部是唯一的 RIA 起源于 $\lambda = 1.55\,\,\mu \text{m}$ 在如此强辐射场的 PSF 中。发现空心光纤在整个活动中具有第零个 RIA。