为了实现对球面镜真空紫外光谱反射率的直接测量, 构建了一套真空紫外光谱反射率测试系统。 该系统以氟化镁窗口氘灯与Seya-Namioka凹面光栅单色仪产生单色光源, 反射式调制器与参考探测器做光学补偿, 内径80 mm的荧光积分球与精密转台作为接收系统。 光学补偿消除单色光源不稳定性, 荧光积分球消除了两次测量光斑不同对探测器响应的影响, 且减少了系统的能量损失。 利用该系统测量了115～180 nm球面镜的反射率, 测试结果表明测量重复性优于±0.3%; 按国际通用不确定度评估规范, 对系统进行不确定度分析, 相关不确定度小于1.3%。 实现了球面镜反射率的高精度测量。

In order to directly measure the vacuum ultraviolet spectrum reflectance of spherical mirror a measurement system was established. The system consists of monochromatic light source with deuterium lamp of magnesium fluoride window and Seya-Namioka concave grating monochromator, optical compensator with reflection modulator and reference detector and the receiving system with 80 mm diameter fluorescence integrating sphere and precision turntable. The optical compensation eliminates the instability in monochromatic light source, and the fluorescence integrating sphere eliminates the impact of light spot sizes in the two measurements, and reduce the system energy loss. The system measures the spherical mirror reflectivity in 115~180 nm, and the measurement result show that the repeatability is less than ±0.3%, and the relative uncertainty is less than 1.3%. The spherical mirror reflectivity achieves high-precision measurement.