Development of advanced thin foil substrate for large X-ray telescope

Wolter I型光学系统是X射线天文学中应用最广泛的光学系统，由共焦抛物面和双曲面反射镜组成。我们建议开发一种先进的薄箔基板具有沃尔特光学未来的大型X射线望远镜具有高的空间分辨率。我们的研究目标是通过液压机和热成形从一张薄箔制成具有Wolter几何形状的先进薄箔，并演示具有Wolter几何形状的薄箔的复制。(1)Wolter形两级箔的开发我们压制了一张Mg箔，其具有200 mm/级的长度和0.3 mm的厚度，并且形成了具有约+/-30 mm的峰-峰值的形状误差的Wolter形箔。图形误差使我们能够进行复制，以实现薄箔上的光滑表面。首次将镁箔用作望远镜基片，镁合金对减轻X射线望远镜的重量是有益的。(2)两级箔的复制已经建立了短箔（100 mm长）的复制，但长薄箔（400 mm/两级）的复制是我们的第一个实验。我们与名古屋大学合作，尝试复制两阶段花剑。具有光滑表面的薄箔成功地从玻璃心轴复制。我们评价了图像质量的薄箔与ISAS X射线束设施。虽然X射线波段的成像质量受到玻璃芯轴精度的限制，但我们展示了薄箔的复制。通过这项研究，我们获得了制造大型X射线反射镜的关键技术。这种技术是必要的制造一个大型的X射线望远镜具有高空间分辨率进行未来的X射线任务。

Wolter type-I optics, which are the most widely used in X-ray astronomy, consists of confocal paraboloidal and hyperboloidal reflectors. We proposed to develop an advanced thin foil substrate having the Wolter optics for future large X-ray telescopes with a high spatial resolution. The goals of our research are make an advanced thin foil with the Wolter geometry from one sheet of thin foil by hydraulic press and thermal forming, and to demonstrate replication of the thin foil with Wolter geometry.(1) Development of the Wolter shaped two-stage foilWe pressed one sheet of Mg foil which has a length of 200 mm/stage and a thickness of 0.3 mm, and formed a Wolter shaped foil with a figure error of about a peak-to-peak value of +/-30mm. The figure error enables us to make a replication to realize a smooth surface on the thin foil. The use of Mg foil for a telescope substrate is the first experiment, and Mg alloy is useful to reduce weight of X-ray telescope.(2) Replication of the two-stage foilReplication of a short foil (100mm long) has been established, but the replication of a long thin foil (400mm/two-stage) was the first experiment for us. We tried replication of the two-stage foil in collaboration with Nagoya University. The thin foil with a smooth surface was successfully replicated off from a glass mandrel. We evaluated an image quality of the thin foil with the ISAS X-ray beam facility. Although the image quality in the X-ray band is limited by an accuracy of our glass mandrel, we demonstrated the replication of the thin foil.Through this research, we obtained the key technique to make a large X-ray mirror. This technique is necessary for fabrication of a large X-ray telescope with a high spatial resolution carried on future X-ray missions.