【作者】 邓涛；

【导师】 谢峻林；

【作者基本信息】 武汉理工大学 ， 材料学， 2010， 博士

【摘要】 近年来,石英玻璃及石英光纤在辐射环境下的应用逐渐引起了人们的广泛关注,但研究者们在关于材料组成对两者的抗辐射性能的影响、不同辐射条件下的辐致损伤等问题的理解上存在一定的分歧。为了进一步研究石英玻璃及光纤的辐致损伤机制和影响因素,为制备具有较高抗辐射性能的石英光纤奠定理论基础,本文以等离子体化学气相沉积工艺(PCVD)制备的高纯、掺杂石英玻璃及石英光纤为研究对象,分析了掺杂对石英玻璃结构以及抗辐射性能的影响,对比了不同材料组成的石英光纤的抗辐射性能,研究了辐致损耗与辐射条件之间的相关性,同时就石英光纤抗辐射性能的优化开展了一些研究工作。主要研究内容和结论如下：(1)红外光谱及Raman光谱测试结果表明,氟在石英玻璃中的存在状态为[SiO3F],氟的引入将增大断网几率,减少石英玻璃中的三元环与四元环等结构。石英玻璃的抗辐射能力随着掺F量的增加而增加。电子自旋共振谱(ESR)测试结果表明,纯石英玻璃及掺氟石英玻璃在200-900nm波段的吸收主要来自于SiE’心,对SiE’心的形成机制进行了解释,并给出了SiE’心吸收与辐照剂量之间的函数关系。(2)在掺锗石英玻璃Raman光谱中,既出现了[SiO4]、[GeO4]的特征振动峰,如Si-O-Si伸缩振动峰(1060cm-1)以及Si-O-Si弯曲振动(420cm-1)与Ge-O-Ge弯曲振动(440cm-1)相叠加后的强峰,同时也出现了Ge-O-Si的振动峰(675cm-1),说明出现了[SiO4]和[GeO4]之间的相互连接现象,同时采用二能级理论模型对三元环与四元环特征峰的变化进行了解释。单掺锗石英玻璃的抗辐射能力随着锗含量的增加而恶化,辐照之后出现了大量与锗有关的色心,色心的吸收主要在193nm、213nm、242nm以及300nm附近,这些色心使得石英玻璃在紫外波段的吸收增加、透过率下降。此外,将ESR结果与吸收光谱结果进行了关联,对掺锗石英玻璃中的缺陷进行了辨认。研究表明：300nm的吸收与Ge(1)心的浓度符合良好的线性,而213nm的吸收与GeE’心浓度之间不存在线性关系。(3)在介绍石英光纤材料组成与结构的基础上,提出了PCVD工艺在制备抗辐射光纤方面的优势,简要分析了抗辐射光纤产品的开发思路。对比研究了三种不同结构组成的单模光纤的抗辐射性能,它们的抗辐射能力由高到低顺序为：纯硅芯光纤>采用功能梯度概念设计制造的氟锗共掺单模光纤>单掺锗石英芯单模光纤。同时评估了一种普通多模光纤在不同辐照条件下抗辐射能力。光纤的折射率剖面测试结果表明,即使较高剂量(10kGy/h×10h)的Gamma射线辐照也不会对光纤的波导结构造成明显影响。此外,结合ESR结果给出了光纤中引起辐致吸收的缺陷的转变过程,得到了单模光纤在1550nm、多模光纤在1300nm波段的辐致损耗与辐照条件之间的函数关系,借由此关系可以对光纤的抗辐射能力给出预估。(4)研究纯硅芯单模光纤以及氟锗共掺单模光纤的抗辐射性能对拉丝工艺的依赖性发现,前者受拉丝工艺影响较大,后者受拉丝工艺影响小,因而更适合规模生产。对比单独载氢以及预辐照结合载氢对光纤抗辐射性能的优化效果,结果表明预辐照结合载氢更有助于改善光纤的抗辐射性能。这对于图象传输用光纤具有较大意义。更多还原

【Abstract】 In recent years, the applications of silica glass and silica optical fibres in the radiation environment aroused extensive attention of the researchers. There are different opinions of the influence of material structure on the radiation resistance properties of silica glass and silica optical fibres. Arguments are never stopped on the radiation-induced defect in different radiation conditions. In this dissertation, the pure silica glass, doped silica glass and optical fibres fabricated with PCVD process are taken as the study objects, in order to further study the radiation-induced defect mechanism and concerned influence factors, to lay a foundation for the production of high quality radiation resistance optical fibres. The dopant influences on the structure of silica glass and radiation resistance properties are researched. The radiation resistance propertiesof optical fibres with different structures are compared. The relationship between radiation-induced losses of optical fibres and radiation conditions is studied. The improvement of optical fibre’s radiation resistance properties is considered as well. The main contents and conclusions are as follows:(1) By analyzing the Si-F bond vibration absorption bands from the infra-red spectrum and Raman spectrum of Fluorine doped silica glass, it was found that Fluorine exists in silica networks as the formation of [SiO3F]. The introduction of Fluorine will increase the probability of bond broken, and decrease the structures of 3-fold rings and 4-fold rings. Consequently, the radiation resistance properties of silica glass will be improved with the increase of the Fluorine doped quantity. According to the UV-VIS spectrum combined with ESR test results, the absorptions of the pure silica glass and doped silica glass in 200 to 900 nm are mainly contributed by SiE’ centers. In this dissertation, the formation principle of SiE’ centers was researched. The functional relation of the SiE’absorbance and radiation dose was explained as well.(2) By analyzing the Raman spectrum of Ge doped silica glass, the Si-O-Si stretching band (1060cm-1), the overlap of bending vibration of Si-O-Si(420cm-1) and Ge-O-Ge(440cm-1) were observed. The vibration band of Ge-O-Si at 675cm-1 were observed as well. It has been proved that the linkage between [SiO4] and [GeO4] in Ge-doped silica glass exists. Based on the two level energy model, the change of 3-fold rings and 4-fold rings band was explained. The radiation resistance properties of silica glass will be deteriorated with the increase of the Germanium doped quantity. After radiation, plenty of Ge-related color centers were found. The Ge-related color centers are mainly located around 193nm,213nm,242nm and 300nm which will cause the absorption increase and permeation decrease in the ultraviolet band. Combined the ESR test results and optical absorption spectrum, the flaws in Ge-doped silica glass were identified. After calculation, it was demonstrated that there is linear relationship between the absorption peak value at 300nm and the Ge(1) center concentration. Besides, no linear relationship was found between the absorption peak value at 213nm and the GeE’center concentration.(3) With the introduction of material structure of silica optical fibre, the advantages of PCVD process used for the fabrication of radiation resistant optical fibre are analyzed. Three kinds of single mode optical fibres with different structures were compared:the pure silica core optical fibre has the best radiation resistance, the F-Ge co-doped optical fibre with functional graded material design takes the second place, and the Ge-doped silica core optical fibre is the worst. Different radiation conditions on the same multimode optical fibres were evaluated as well. Based on the refractive index (RI) test results, it has been proved that even with high radiation dose (10kGy/h×10h), the Gamma irradiation will not influence the waveguide structures obviously. Based on the ESR test results, the transition process of radiation induced defects in optical fibres was researched. Functional relation between the radiation induced losses (SMF at 1550nm and MMF at 1300nm) and radiation conditions was concluded. It could be used for the pre-evaluation of the radiation resistance properties of the optical fibres.(4) The radiation resistance properties are dependent of the drawing process. The pure silica core optical fibre is more sensitive with the drawing process, and the Ge-F co-doped single mode fibre is insensitive with the drawing process, which is more suitable for large scale production. Comparing the effect of hydrogen treatment with that of pre-radiation plus hydrogen treatment, it has been proved that the later is more effective on optimizing the radiation resistance properties of the optical fibre. This is especially meaningful for the image-guide-used optical fibres.更多还原