大口径天文光学望远镜主镜镀膜的研究

发布时间：2018-06-12 15:54

本文选题：镀膜 + 大口径天文光学望远镜　；参考：《中国科学院研究生院（云南天文台）》2013年博士论文

【摘要】：大口径天文光学望远镜工作时，主镜直接与大气接触，指向天空。长期观测下来，大气中的污染物如灰尘颗粒和酸性颗粒落到主镜上不断累积，降低望远镜主镜的反射率并腐蚀镜面金属反射膜，使得主镜面的漫反射加强，进入系统探测器的杂散光加大。通过定期对主镜进行清洗的办法可适当缓解主镜光学性能的降低速度。为了使天文望远镜保持最佳的观测效果，需要每隔2-3年，对大口径天文光学望远镜主镜重新镀反射膜一次。本论文利用国内第一台自上向下，蒸镀天文望远镜主镜铝反射膜的大型镀膜机ZZ3200对天文望远镜主镜镀膜展开了深入而又全面的研究，讨论了天文望远镜主镜反射膜的膜层材料、均匀性、分子动力学模拟等镀膜技术相关问题，研究了镀膜过程中的主镜室结构、镀膜机控制参数、旧膜脱膜、清洗等问题，，最后针对目前国内拥有最大的单块天文主镜的丽江2.4米望远镜主镜镀膜开展研究工作，最终完成丽江2.4米望远镜主镜镀膜工作。论文首先对天文望远镜主镜金属反射膜材料的选择，结合ZZ3200镀膜机蒸发源布局讨论了铝反射膜的膜厚不均匀性及不均匀性对望远镜成像质量的影响。然后对天文望远镜主镜的保护膜进行了研究，分别分析了保护膜对主镜反射率的影响，和保护膜对天文光学望远镜主镜旧膜脱膜的影响。利用ZZ3200镀膜机，分别对天文望远镜主镜镀制铝反射膜时铝膜和保护膜分子动力学过程进行分析。以丽江2.4米望远镜主镜镀膜整个过程进行规划，包括镀膜前期准备，镀膜过程中的旧膜脱膜、镀膜机参数控制等关键问题进行了讨论，形成了固定的工艺文档。基于上述分析研究，于2012年10月，使用ZZ3200镀膜机，完成了对丽江2.4米望远镜主镜的镀膜工作，并定制云南天文台2.4米望远镜主镜镀膜的技术规范及相关工艺卡片，可为我国以后大型天文望远镜主镜镀膜工作提供参考与借鉴。经过陪镀片测试，2.4米望远镜主镜反射膜在350~1100nm范围内平均反射率87.16%。丽江2.4米望远镜主镜完成后，无论成像观测还是光谱实测，观测结果表明极限星等提高超过1个星等。
[Abstract]:When the large-aperture astronomical optical telescope works, the primary mirror is in direct contact with the atmosphere and points to the sky. Over a long period of time, pollutants such as dust particles and acidic particles in the atmosphere have been continuously accumulated in the primary mirror, reducing the reflectivity of the telescope's primary mirror and corroding the mirror metal reflection film, thus strengthening the diffuse reflection of the primary mirror. The stray light entering the system detector increases. By cleaning the primary mirror regularly, we can reduce the speed of the optical property of the primary mirror. In order to keep the best observation effect of the astronomical telescope, it is necessary to recoat the reflection film on the primary mirror of the large aperture astronomical optical telescope every 2-3 years. In this paper, a deep and comprehensive study on the primary mirror coating of astronomical telescope is carried out by using ZZ3200, the first domestic top-down, evaporating primary mirror aluminum reflection film, and the coating material of the primary mirror reflection film of astronomical telescope is discussed. Homogeneity, molecular dynamics simulation and other problems related to coating technology are studied in the process of coating, such as the structure of primary mirror chamber, the control parameters of coating machine, the de-coating of old film, cleaning and so on. Finally, the primary mirror coating of Lijiang 2.4m telescope with the largest single primary mirror in China is studied, and the primary mirror coating of Lijiang 2.4m telescope is finally completed. In this paper, the material selection of metallic reflection film for primary mirror of astronomical telescope and the distribution of evaporation source of ZZ3200 coating machine are discussed in this paper. The influence of non-uniformity of film thickness on imaging quality of telescope is discussed. Then the protective film of primary mirror of astronomical telescope is studied. The influence of protective film on primary mirror reflectivity and the influence of protective film on the old film of primary mirror of astronomical optical telescope are analyzed respectively. Using ZZ3200 coating machine, the molecular dynamics process of aluminum film and protective film were analyzed respectively when the primary mirror of astronomical telescope was coated with aluminum reflection film. The whole process of the primary mirror coating for Lijiang 2.4m telescope was planned, including the preparation of the coating period, the decoating of the old film during the coating process, the parameter control of the coating machine, and so on, and the fixed process documents were formed. Based on the above analysis, in October 2012, the primary mirror of Lijiang 2.4m telescope was coated with ZZ3200 coating machine, and the technical specifications and related process cards for the primary mirror coating of 2.4m telescope of Yunnan Observatory were customized. It can be used as reference for the primary mirror coating of large astronomical telescope in China. The average reflectivity of the 2.4m telescope primary mirror reflector in 350~1100nm range is 87.16. After the completion of the primary mirror of Lijiang 2.4m telescope, whether imaging observation or spectral measurement, the observation results show that the limit magnitude is increased by more than one magnitude.
【学位授予单位】：中国科学院研究生院（云南天文台）
【学位级别】：博士
【学位授予年份】：2013
【分类号】：P111.2

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