Development of precision Wolter mirrors for future solar x-ray observations
Development of precision Wolter mirrors for future solar x-ray observations
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开发用于未来太阳 X 射线观测的精密 Wolter 反射镜
DOI：
10.1117/12.2188905
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
N.
中科院分区：
文献类型：
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作者：
Sakao;T.;Matsuyama;S.;Kime;A.;Goto;T.;Nishihara;A.;Nakamori;H.;Yamauchi;K.;Kohmura;Y.;Miyake;A.;Hashizume;H.;Maezawa;T.;Suematsu;Y.;and Narukage;N.
太阳X射线日冕的高分辨率图像为理解那里等离子体粒子的动力学和加热过程提供了关键的关键。然而，由于制造精确的沃尔特镜存在严重的技术困难，尚未进行亚弧秒分辨率的太阳X射线成像。对于未来的太阳日冕的X射线观测，我们正试图通过采用先进的表面抛光和基于纳米技术的计量方法来实现亚弧秒分辨率的精确Wolter镜，以扇区反射镜组成整个环形的一部分。于二零一三年制造第一面工程镜及随后评估X射线聚焦性能后，制造第二面工程镜，并引入精密抛光及计量方面的改进。在SPring-8同步加速器设施上使用8 keV X射线测量第二反射镜的聚焦性能表明，PSF核心的FWHM尺寸达到0.2”，而其HPD（半功率直径）尺寸保持在~3”，这是由于核心外部存在小角度散射。此外，弧矢聚焦和弧矢聚焦之间的焦距存在显著差异，这可能是由反射镜区域中弧矢方向上<10 nm的下垂误差引起的。为克服这些问题，已计划在下一个工程镜像中进行进一步改进。
High resolution imagery of the solar X-ray corona provides a crucial key to understand dynamics and heating processes of plasma particles there. However, X-ray imagery of the Sun with sub-arcsecond resolution has yet to be conducted due to severe technical difficulty in fabricating precision Wolter mirrors. For future X-ray observations of the Sun's corona, we are attempting to realize precision Wolter mirrors with sub-arcsecond resolution by adopting advanced surface polish and metrology methods based on nano-technology to sector mirrors which consist of a portion of an entire annulus. Following fabrication of the first engineering mirror and subsequent evaluation on the X-ray focusing performance in 2013, the second engineering mirror was made with improvements in both precision polish and metrology introduced. Measurement of focusing performance on the second mirror at SPring-8 synchrotron facility with 8 keV X-rays has demonstrated that the FWHM size of the PSF core reached down to 0.2" while its HPD (Half Power Diameter) size remained at ~3" due to the presence of small-angle scatter just outside of the core. Also, there was notable difference in the focal length between sagittal and meridional focusing which could have been caused by an error in the sag in the meridional direction of <10 nm in the mirror area. Further improvements to overcome these issues have been planned for the next engineering mirror.