【摘要】 介绍了γ射线对光纤的辐射效应,开展了稳态、瞬态γ辐射对光纤的感生损耗测量实验。计算了光纤在高剂量率脉冲γ辐射作用下的电子密度、电子与中性原子的碰撞频率、等离子体振荡频率,提出了基于低温等离子体对光波吸收的瞬态辐射感生损耗模型,计算了光纤在600～1600 nm的瞬态辐射感生损耗并与实验测量结果进行了对比分析。结果表明:(1)在1310 nm和1550 nm波长,光纤的瞬态辐射感生损耗的计算结果与实验测量结果在相同数量级,实验测量结果验证了等离子体吸收模型的适用性;(2)脉冲γ射线作用于光纤时,等离子体吸收与原子缺陷吸收同时存在,光纤的瞬态辐射感生损耗是两种机制共同作用的结果;(3)在600～1600 nm光谱范围内,随探测波长的增大,光纤的辐射感生损耗以等离子体吸收为主。更多还原

【Abstract】 General effect mechanisms of available fused silica optical fibers to nuclear radiation were introduced.Measurement experiments for radiation-induced losses of optical fibers were completed under steady and transient γ radiations respectively.The density of Compton electrons,the electronic oscillation frequency and the collision frequency between electrons and neutral atoms were computed under the pulsed radiation conditions with high dose rate.A method was presented that it could use the absorption model of low temperature plasma on light-wave to analyze the transient effects of nuclear radiation on optical fibers,and the radiation-induced absorption losses within wavelength range of 600-1600 nm were calculated.The results show that:(1) the transient radiation-induced absorption losses are in the same orders of magnitude comparing to the experimental results when the detecting wavelengths are 1310 nm and 1550 nm.The model could be used for analysis of transient radiation-induced loss of optical fiber under pulsed nuclear radiation;(2) both low temperature plasma absorption and atomic energy level defects absorption mechanisms exist simultaneously,therefore,transient radiation-induced loss of optical fiber is the result of joint action of the two;(3) the absorption of low temperature plasma is the dominant factor causing transient radiation-induced losses in the longer wavelength in the spectral range of 600-1600 nm.更多还原