为了满足类氖-锗X射线激光研究的需要,设计制备了23.4 nm软X射线多层膜反射镜。依据多层膜选材原则并考虑材料的物理化学特性选择新的材料Ti与Si组成材料对。设计优化材料多层膜的周期厚度(d),材料比例(Γ),周期数(N),计算出Ti/Si反射率曲线。通过实验优化各种镀膜工艺参数,制备出了23.4 nm的Ti/Si多层膜反射镜。利用X射线衍射仪和软X射线反射率计对Ti/Si多层膜结构和反射率进行检测,测量结果为Ti/Si多层膜反射镜中心波长0λ=23.2nm,正入射峰值反射率为R=25.8%。将Ti/Si多层膜反射镜与软X射线波段常用的Mo/Si多层膜反射镜相比,在23.4 nm处,Ti/Si多层膜反射镜的反射率提高10%,而带宽减小1.8 nm,光学性能显著提高。
To meet the research requirement of Ne-like Ge X-ray laser,we designed and fabricated soft X-ray multilayer mirrors at 23.4 nm.New material combination Ti/Si has been chosen based on the material selecting rule,considering the optical characteristics and physicochemical characteristics.Then the period thickness(d),material ratio(Γ),and period number (N) of the multilayer were optimized and the reflectivity was calculated by software.The coating parameters were optimized through experiments and the Ti/Si multilayer mirrors at 23.4 nm were fabricated by magnetron sputtering coating machine.The mirrors were tested by X-ray diffractometer and soft X-ray reflectometer after fabrication.The test results of the Ti/Si multilayer were λ0=23.2 nm and R=25.8%.Compared with Mo/Si multiplayer,which is generally used in soft X-ray region,the reflectivity of Ti/Si multilayer increases 10% approximately, and FWHM narrows by 1.8 nm at 23.4 nm,indicating better optical performance.