依据材料的质量吸收系数和波长的关系,选择Cr和Al 设计和制备30.4 nm自支撑滤光片。在制备时以NaCl为脱膜剂,以热蒸发方式蒸镀Al,以电子束蒸发方式蒸镀Cr,制备了30.4 nm的Cr/Al/Cr自支撑滤光膜,并对滤光片的表面缺陷进行了分析。通过显微镜观察,滤光膜均匀纯净,无明显针孔。Cr/Al/Cr自支撑滤光片在合肥国家同步辐射实验室进行了测量,Cr/Al/Cr厚度为5 nm/500 nm/5 nm和12.5 nm/500 nm/12.5 nm的滤光片在30.4 nm波长处的透过率分别为7.6%和4.6%,透过率曲线和理论计算基本一致。用紫外分光光度计测量得滤光片在200～800 nm波长范围的透过率小于0.02%,满足使用要求。

In this paper Cr and Al were chosen to design the 30.4 nm filter of self-supporting thin film based on relation between mass absorption coefficient and wavelength. In the preparing course NaCl was chosen as parting agent,Al was deposited by thermal evaporation and Cr was deposited by electron-beam evaporation,finally the 30.4nm Cr/Al/Cr filter of self-supporting thin film was prepared successfully. Observed under microscopy the surface topography of filter was clean and uniformity,no apparent pinholes appeared on the surface. The Cr/Al/Cr filters were measured in synchrotron radiation laboratory in Hefei,the transmittance of Cr(5 nm)/Al(500 nm)/Cr (5 nm) filter and Cr(12.5nm)/Al(500 nm)/Cr(12.5 nm) filter was 7.6% and 4.6% at the wavelength of 30.4 nm,respectively,the measured transmittance curves were in accordance with the prediction design generally. The transmittance of the filter was less than 0.02% from 200 nm to 800 nm measured with ultraviolet spectrophotometer,satisfying the requirement of use. Finally the surface defects of the filter were analyzed.