Development of X-Ray Multilayer Aspheric Mirrors by Replication Technology and Nano-Structure Analysis

在玻璃柱上沉积Pt/C多层膜后，我们将铝箔粘在上面，并在带有红外加热器的真空室中固化。从玻璃圆柱体上分离出铂碳多层膜铝箔反射镜，并将其作为复制的薄箔反射镜用于硬X射线望远镜。U.S.A.by在浮动抛光的化学镀镍平面上镀上Pt/C多层膜，再用环氧树脂将其与平整的玻璃板粘合，可以很好地将Pt/C多层膜与化学镀镍平面分离。通过高分辨透射电子显微镜（TEM）对硅片上镀Pt/C多层膜的断面观察，发现C层为非晶态结构，Pt层为取向的多晶纳米结构，这是造成两层界面粗糙度的主要原因。在Pt/C多层膜中，当层间距小于3 nm时，界面粗糙度随层间距的减小而增大，通过在非球面管芯和第一层Pt层之间增加一层Ti中间层，我们可以将Pt/C多层膜从化学镀镍模具中分离出来，得到Pt/C多层膜复制的硬X射线内反射镜。采用该工艺制作了直径为6 mm的镀金非球面内反射镜，获得了面形精度为72 nm、表面粗糙度Ra为1 nm的非球面X射线复制收集镜。在此基础上，研制了图像分辨率小于50 nm的软X射线显微镜。

After depositing Pt/C multilayer on a glass cylinder, we glued aluminum foil on it and cured in a vacuum chamber with an infrared heater. Pt/C multilayer mirrors on aluminum foils were separated from the glass cylinder and were used in a hard X-ray telescope as replicated thin foil mirrors. The telescope was lunched several times in U.S.A.by balloons for observing hard X-ray objects in a space.The float-polished electroless nickel plane was coated with Pt/C multilayer and glued with a flat grass plate using epoxy resin, and we could separate the Pt/C multilayer from the electroless nickel plane perfectly. The surface roughness was 0.14nm rms on the electroless nickel plane and 0.16nm rms on the Pt/C multilayer mirror, respectively.The high resolution transmission electron microscopy (TEM) sectional observation of Pt/C multilayer coated on a silicon wafer cleared that C layer showed an amorphous structure and Pt layer showed an oriented polycrystalline nano structure which causes the surface roughness at the interface between two layers. The interface roughness is increased with the decrease of layer spacing less than 3nm in the Pt/C multilayer.By adding an intermediate Ti layer between the electroless nickel aspheric die and the first Pt layer, we could separate the Pt/C multilayer from the electroless nickel die and obtain Pt/C multilayer replicated internal mirrors for hard X-ray application.This technology was used in making a gold plated aspheric inner mirror of 6 mm in diameter and we obtained aspheric X-ray replicated collecting mirrors of 72nm in shape accuracy and 1nm Ra in surface roughness. Then we made a soft X-ray microscope of less than 50nm in image resolution.