铝漫反射板200～300 nm相对双向反射分布函数的实验研究

选择了合适的测量方式．建立了铝漫反射板的相对双向反射向反射分布函数的测量装置。通过实验研究铝漫反射板的相对双向反射分布函数在不同情况下的性质表明：不同表面粗糙度的铝漫反射板相对双向反射分布函数随入射角度的变化趋势有所不同；表面镀A1 MgF2膜反射率可增大约1．5到3倍；相对双向反射分布函数在200～280nm之间不随波长改变，波长大于280nm时，随波长略有增加，最大13％。根据实验数据绘出的二维等值线图反映了光辐射以不同角度入射、观测角度固定情况下的铝漫反射板的相对双向反射分布函数的变化，对实验数据拟合得到在该情况下的铝漫反射板的相对双向反射分布函数的较精确的数学表达式。

Bidirectional Reflectance Distribution Function of Aluminium Diffuser at UV Spectral Band

The experimental setup for the measurement of aluminium diffuser′s bidirectional reflectance distribution function has been established by choosing a proper illuminating and viewing method. Characteristics of aluminium diffuser′s bidirectional reflectance distribution function under different situation are studied in experiment. The change trends of bidirectional reflectance distribution function with wavelength of different surfaces roughness of Al diffusers are different; after coated with Al+MgF2,the reflectance increase approximately from 1.5 to 3 times; from 200 to 280 nm, the relative bidirectional reflectance distribution function of Al diffuser does not change with wavelength, but it increases up to 13 percent while wavelength is longer than 280 nm. Contour plots resulting from experimental data show the change of aluminium diffuser′s bidirectional reflectance distribution function with different illuminating angles while viewing angles are fixed, a fitted empiristic formula in such case is given, its relative accuracy is 2.4 percent.