聚变反应速率测量光学系统设计

基于塑料闪烁体和条纹相机设计了聚变反应速率测量系统,论述了测量光学系统的工作原理和设计方法。通过设置防辐射石英玻璃窗,防止了光学元件受强X射线辐射而变暗;采用晶体等紫外透过率高的光学材料,满足了光学系统对透过率的要求;光学系统像面与条纹相机的阴极面直接对接,解决了条纹相机孔径不匹配的问题;最后在一次像面设置场镜,大幅缩小了光学元件的口径。设计的光学系统总长为2 660mm,放大倍率为1/3,像方F/#数达到0.667,系统透过率达到67%,时间弥散小于7.3ps。这些结果能够适应不同中子产额的实验需求,在激光打靶实验中取得了较好的实验效果。

Design of optical system for fusion reaction-rate measurement

Based on a plastic scintillator and an optic streak camera, a measuring system for fusion reaction-rate was designed, then the working princile and design method of the measuring system were addressed in detail. A piece of fused silica window was set just behind the plastic scintillator to protect optical elements from darkening after a long time exposure in scatted X rays and the ultraviolet crystals and other ultraviolet glass were selected to ensure the high system transmission. Furthermore, the image plane of the optical system was put onto a photocathode of the streak camera directly to remove the aperture non-matching of input optic system of the streak camera. Finally, a field mirror was put on the first image plane to reduce the max diameter of optical element from 160 mm to 120 mm. The designed optical system has a total length of 2 660 mm, magnification of 3∶1 and its final lens is F/0.667 and transmission is 67%. Moreover, the time dispersion of the optical system is less than 7.3 ps. These results meet the experimental needs of different neutron yields and good experimental results have been obtained in a laser targeting experiment.