Research on High Sensitivity FiberOptic Radiation Dosimeter

To develop an all-fiber radiation monitoring device for radiation monitoring in the space station, the radiation-induced attenuation characteristics of fiber were investigated by a theoretical model of the radiation effect of silica-based optical fibers. The radiation sensitivity of commercial optical fibers such as rare-earth-doped fibers, boron-doped fibers, and high germanium-doped fibers under gamma radiation was studied using a ⁶⁰Co-γ radiation source to simulate the space environment. It was found that rare-earth doped fiber has significant radiation-sensitive characteristics, boron doped fiber and high germanium doped fiber also exhibit little radiation-sensitive characteristics. Especially, Erbium-doped fiber has the strongest radiation sensitivity, the rate of radiation-induced attenuation is about $\mathbf{4.45}\times \mathbf{10}^{-\mathbf{4}}\sim \mathbf{1.13}\times \mathbf{10}^{-\mathbf{3}}$ dB/m/rad (Si). In addition, the relationship between the light source and radiation sensitivity characteristics of optical fiber was also studied. It was found that the radiation sensitivity of the optical fiber is related to the wavelength. The radiation sensitivity of optical fiber decreases monotonously with the increasing wavelength. Based on the above research, an all-fiber irradiation dosimeter with a 1310nm DFB light source and an Er80/125 fiber model was developed. The measurement showed that the output light intensity of the fiber attenuated by 0.0075dB within 7 days, and the estimated radiation dose was 0.843 rad (Si).