球冠型入射光学系统中等效辐射平面位置的计算

Calculation of the Equivalent Radiation Plane for the Spherical Entrance Optics

为了满足包括太阳直射和天空散射在内的2π球面度立体角范围的入射光线的测量需求,要求太阳紫外光谱辐射测量装置的入射光学系统必须具备较好的余弦响应特性。研制的入射光学系统由聚四氟乙烯积分球、磨砂石英球冠型余弦漫射器和修正环组成。

The ideal cosine entrance system is required for measuring the total radiation of the solar including the direct radiation and the diffuse radiation over a solid angle of 27π steradian on the surface of the Earth. A new combination entrance optics is developed with the integral cosine error 〈 f2 〉 = 0.94% , which is composed by a polytetrafluoroethylene （FIFE） integrating sphere, a spherical ground quartz diffuser and a special correction ring. The conception of equivalent radiation plane receiver is introduced, the mathematic calculation and experimental method are presented and compared to determine the position of the equivalent radiation plane according to the information of geometrical shape of the diffuser, the different irradiance value on the spherical surface, and the angular response of the receiver. The uncertainty of calibration of the solar UV spectroradiometer will be improved when the method of equivalent radiation plane is adopted.