Sebag Jacques, Andrew John, Neill Douglas, Warner Michael
National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, Arizona 85719, USA.
Appl Opt. 2010 Aug 20;49(24):4610-20. doi: 10.1364/AO.49.004610.
Temperature and strain measurements obtained during coating of spin-cast borosilicate samples are presented here with an analysis of these results. These tests were performed for the Large Synoptic Survey Telescope (LSST) project to verify the possible use of sputtering deposition of optical coating on its large 8.4m diameter primary-tertiary mirror. Made of spin-cast borosilicate glass, the working stress of the mirror's nonpolished surfaces is 100 psi (0.69 MPa), resulting in a local temperature difference limit of 5 degrees C. To ensure representative environmental conditions, the tests were performed in the Gemini Observatory coating chamber located in Hawaii, whose design was utilized to develop the LSST coating chamber design. In particular, this coating chamber is equipped with linear magnetrons built with cooled heat shields directly facing the mirror surface. These measurements have demonstrated that it will be safe for the LSST to use a magnetron sputtering process for coating its borosilicate primary-tertiary mirror.
本文展示了在旋铸硼硅酸盐样品镀膜过程中获得的温度和应变测量结果，并对这些结果进行了分析。这些测试是为大型综合巡天望远镜（LSST）项目进行的，以验证在其直径8.4米的大型主次镜上溅射沉积光学涂层的可行性。该镜子由旋铸硼硅酸盐玻璃制成，其未抛光表面的工作应力为100磅力/平方英寸（0.69兆帕），导致局部温差限制为5摄氏度。为确保具有代表性的环境条件，测试在位于夏威夷的双子座天文台镀膜室中进行，该镀膜室的设计被用于开发LSST镀膜室设计。特别是，这个镀膜室配备了线性磁控管，磁控管带有直接面向镜面的冷却隔热罩。这些测量结果表明，LSST使用磁控溅射工艺为其硼硅酸盐主次镜镀膜是安全的。
