在北京同步辐射装置上, 利用经过标定的硅光二极管作为标准探测器, 对金、铝两种阴极的X射线二极管灵敏度进行了绝对测量。由于光源中二次谐波的影响, 会造成计算所得的灵敏度降低。为了消除二次谐波的影响, 实验中采用透射光栅对光源的二次谐波份额进行测量, 并以此为依据对计算所得的灵敏度进行修正。通过光阴极次级电子发射模型对二次电子转换效率进行了分析, 并且利用分析结果对缺省能点的阴极灵敏度进行了计算。同时对影响灵敏度计算的各种因素进行分析, 最终得到的X射线二极管光阴极灵敏度的相对不确定度小于3%。

With the calibrated silicon photodiode as standard detector, the sensitivity of X-ray diodes (XRDs) with different photocathodes (Al and Au) has been absolutely measured on the Beijing Synchrontron Radiation Facility. The 2nd-order harmonic in the light source will cause the derived sensitivity to decrease. In order to eliminate this effect, a transmission grating was used to measure the share of the 2nd-order harmonic, and the result was utilized to correct the derived sensitivity of XRDs. A simple model for secondary electron emission of photocathode was presented, and the conversion efficiency of secondary electron was analyzed. The sensitivity in the energy range without experimental data was then calculated through the model. The uncertainty analysis was also carried out, and the resulting relative uncertainty of sensitivity was smaller than 3%.