软X射线反射法测量金属W的光学常量

在同步辐射装置3W1B光束线上测量了软X射线能区50~200 eV金属W薄膜的反射率,并采用最小二乘拟合得到其光学常量.实验采用三种样品：Si衬底单层W超薄膜，Si衬底W/C双层膜，SiO2衬底W薄膜.分别获得金属W光学常量，三种样品的结果分别代表W薄膜光学常量，WC薄膜结合中W薄膜的光学常量及体材料W的光学常量.结果表明,前两者结果与以往发表数据一致性较好，第三种样品的结果则更接近已发表的体材料的结果.通过实验结果和已发表数据的比较，发现随着薄膜厚度的降低，光学常量实部（色散因子）变化不明显，而虚部（吸收因子）随之升高.实验不确定度来源于光谱纯净度和光源稳定性.

Optical Constants of Tungsten from Soft-X-ray Reflectance Measurements

Reflectances of three type Tungsten films(monolayer tungsten film with substrate of Si,monolayer tungsten film with substrate of float glass and W/C biolayer with substrate of Si) were measured on 3W1B beam line of Beijing Synchrotron Radiation Facility (BSRF) in the soft X-ray region 50~200 eV.The optical constant of tungsten film has been obtained with least square curve fitting from the data of reflectance. The results show that the result of the first and the second sample are nearly the same with previously reported data,but the third one accord with the body material almost.It is also found that as the thickness of the film decreased,the imaginary number part (absorption) increased and the real number part（dispersive）changed little.The spectral impurity and stability of the light source has significant effect on calibration.