Novel ultra-lightweight and high-resolution MEMS X-ray optics for space astronomy
Novel ultra-lightweight and high-resolution MEMS X-ray optics for space astronomy
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用于空间天文学的新型超轻量高分辨率 MEMS X 射线光学器件
DOI：
10.1016/j.sna.2012.02.042
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
Kazuo Nakajima
中科院分区：
文献类型：
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作者：
Ikuyuki Mitsuishi;Yuichiro Ezoe;Kensuke Ishizu;Teppei Moriyama;Makoto Mita;Noriko Y.Yamasaki;Kazuhisa Mitsuda;Yoshiaki Kanamori;Kohei Morishita;Kazuo Nakajima
我们报告了我们的新型超轻和高分辨率MEMS x射线光学系统的首次x射线成像测试，用于未来的太空天文任务。我们在厚度为300μm的Si（111）晶圆上制备了单级测试光学器件。我们进行了干蚀刻，并制作了20μm的线和空间通过孔，将其侧壁用作x射线反射镜。我们通过退火和塑料弯曲晶圆片使侧壁平滑，曲率半径为1000mm。我们将Al Kα 1.49keV辐照到测试光学器件上，并首次验证了x射线聚焦。评估的角分辨率范围从26到130角分，比我们的目标15角秒差了两个数量级。我们发现这种分辨率的下降主要是由于侧壁的表面粗糙度很大，可能是由于变形过程。估计的x射线反射率也比假设侧壁平坦的理论值低一个数量级。我们得出结论，这可能是由于粗糙的表面损失了反射面积。因此，为了获得更好的角分辨率和有效面积，未来对大尺度表面粗糙度的改进是必不可少的。
We report on our first X-ray imaging test of our novel ultra-lightweight and high-resolution MEMS X-ray optics for future space astronomical missions. We have fabricated a single-stage test optic made of Si from a Si (111) wafer with a thickness of 300μm. We conducted a dry etching and made 20μm line and space through holes to use their side walls for X-ray mirrors. We have smoothed the side walls by annealing and plastically bending the wafer to a spherical shape with a curvature of radius of 1000mm.We have irradiated Al Kα 1.49keV to the test optic and, for the first time, have verified X-ray focusing. An evaluated angular resolution ranged from 26 to 130arcmin, which is two orders of magnitude worse than our goal of 15arcsec. We found that this degraded resolution is mainly due to a large surface roughness of the side walls >10μm scale and possibly the deformation process. An estimated X-ray reflectivity was also an order of magnitude lower than the theoretical value assuming flat side walls. We concluded that this could be due to the loss of the reflective area by the rough surface. Therefore, the future improvement on the large scale surface roughness is indispensable for the better angular resolution and effective area.