Progress on precise grinding and polishing of thin glass monolithic shell (towards WFXT)
Progress on precise grinding and polishing of thin glass monolithic shell (towards WFXT)
复制标题
薄玻璃整体壳精密磨削抛光研究进展（面向WFXT）
DOI：
10.1117/12.895309
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Citterio O
中科院分区：
文献类型：
--
作者：
Citterio O
下一代宽视场X射线望远镜（WFXT）将要求在宽视场（直径约1 ° 2）内的角分辨率约为5-10角秒，几乎是恒定的。为了实现这一目标，光学系统的设计必须基于以短长度和多项式轮廓为特征的反射镜，以及焦平面曲率和板尺度校正。相对于通常使用的Wolter-I配置，这些概念保证了在大离轴角下提高的角分辨率。因此，这些望远镜最适合用于调查目的。与以前的任务相比，还必须大大增加有效区域和掌握能力。这可以通过高精度但同时薄（对于30-110 cm的镜直径，厚度为2-3 mm）的玻璃镜壳来实现。为了实现5角秒的目标并进一步改进技术，我们正在考虑不同的材料。熔融石英是一种众所周知的材料，具有良好的热机械和抛光特性，是最佳选择。为了使镜面达到所需的精度，我们采用了一种确定性的直接抛光方法（已经用于过去的任务，如爱因斯坦，Rosat，Chandra）。现在的技术挑战是将其应用于几乎薄十倍的壳体。
The next generation wide-field X-ray telescope (WFXT) will require an angular resolution of ~5-10 arcsec almost constant across a wide field of view (~1 deg2diameter). To achieve this goal, the design of the optical system has to be based on mirrors characterized by short length and polynomial profiles, as well as focal plane curvature and plate scale corrections. These concepts guarantee an improved angular resolution at large off-axis angle with respect to the normally used Wolter-I configuration. These telescopes are therefore optimal for survey purposes. A significant increase of effective area and grasp with respect to previous missions must also be achieved. This is possible with high precision but at the same time thin (2-3 mm thickness for mirror diameters of 30-110 cm) glass mirror shells. To achieve the goal of 5 arcsec and improve further the technology, we are considering different materials. Fused silica, a well-known material with good thermo-mechanical and polishability characteristics provide the best choice. To bring the mirror shells to the needed accuracy, we are adopting a deterministic direct polishing method (already used for past missions as Einstein, Rosat, Chandra). The technological challenge now is to apply it for almost ten times thinner shells.