为了得到X射线条纹相机中CsI光阴极的高能电子份额数据, 通过蒙特卡罗方法建立模型来研究CsI光阴极在X射线照射下的光电发射特性。研究了CsI光阴极厚度为100~1000nm、入射X射线能量为1~30keV时的二次电子(SE)能量分布。模拟结果显示, 入射X射线的能量越高、CsI光阴极的厚度越大, 从CsI光阴极出射的二次电子中高能电子(大于50eV)的份额越高, 在入射X射线能量为30keV、CsI光阴极厚度为1000nm时, 出射电子中的高能电子份额可以达到10.8%。但是当CsI光阴极厚度保持为100nm、而入射X射线能量大于15keV时, 高能电子份额维持在3.4%左右而不再随入射X射线的能量增加而增加。

A Monte Carlo model was developed and implemented to calculate the characteristics of X-ray induced secondary electron (SE) emission from a CsI photocathode used in X-ray streak cameras. Energy distributions of emitted SEs were investigated with incident X-ray energy ranging from 1~30keV and a CsI thickness ranging from 100 to 1000nm. Simulation results indicate that the ratio of fast electrons (＞50eV) increases with the energy of the incident X-ray and the thickness of the CsI photocathode. When the energy of the incident X-ray is 30keV and the thickness of the CsI photocathode is 1000nm, the ratio of the fast electrons achieves 10.8%. However, when the thickness of the CsI photocathode is 100nm and the energy of the incident X-ray is higher than15keV, the ratio of the fast electrons is about 3.4% and does not increase with the energy of the incident X-ray.