最小膜层厚度对X射线非周期多层膜光学性能的影响

Influence of the least layer thickness on the characterization of the X-ray non-periodic multilayer

选用能制备小周期的钨/硅(W/S i)作为膜层材料对,着重研究最小膜层厚度对X射线非周期多层膜光学性能的影响。基于矩阵法计算多层膜反射率和单纯形数值优化方法,设计了入射光子能量为8.0keV,掠入射角的宽度分别为0.85°~1.10°,1.40°~1.70°的X射线超反射镜。结合实际实验制备技术,考虑了W/S i两种膜层材料的最小成膜厚度,确定了膜堆中最小膜层厚度为0.5nm^1.0nm。通过改变最小膜层厚度的值,优化设计了上述条件下的非周期多层膜并对其光学性能进行比较。结果表明:同一个工作波长下,随着多层膜工作角度(掠入射)的增加,膜堆中膜层的厚度减小,最小膜层厚度对其光学性能的影响增加,其光学性能变差。

X-ray supermirror is a kind of non-periodic multilayer, the least layer thickness has great effect on its optical characterization. Based on the iterative method of the matrix and the Simplex optimization method, the non-periodic W/Si multilayers were designed with different gazing angle range at the fixed photon energy of 8. 0keV. Considering of the fabrication technology, the least layer thickness was controlled in the range of 0. 5nm-1. 0nm, and hence the different multilayers were obtained. The calculated results show that with the increase of the grazing angle, the layer thickness changes thinner and the influence of the least layer thickness great.