太阳辐照度绝对辐射计的光电不等效性修正

针对绝对辐射计光电不等效性来源复杂、实验测量难度大的特点,提出了修正太阳辐照度绝对辐射计(SIAR)光电不等效性的有限元单元法。结合SIAR的测量方法,对真空中辐射计的腔温响应进行了实验测试。基于有限元单元法,建立了与实验腔温度响应相对误差仅为0.14%的有限元模型,对接收腔的温度响应进行了实验测试。测试结果显示:入射光功率为73.8mW时,接收腔与热沉之间的温度差异约为0.85K,响应的时间常数为29.8s。运用建立的有限元模型对SIAR的光电不等效性进行了评估和修正。结果表明:太阳辐照度绝对辐射计的光电不等效性来源主要为不同加热途径和不同加热区域引起的偏差,SIAR的光电不等效性因子N为0.999 621±0.000 004。该修正模型完善了仪器的修正体系,提高了测量精度,为绝对辐射计的发展提供了可靠的数据来源。

Non-equivalence correction of solar irradiance absolute radiometer

As the non-equivalence of absolute radiometers has complex sources and it is difficult to be measured, this paper proposes the finite element method to correct the non-equivalence of a Solar Irradiance Absolute Radiometer (SIAR).On the basis of the measuring method the SIAR, the nonlinear thermal dynamic response of the cavity in vacuum was tested. A finite element model with a relative error of 0.14% for an experimental cavity was established based on the finite element method to test the temperature response of the receiving cavity. The experimental results show that the temperature difference between the receiving cavity and the heat sink is approximately 0.85 K and the time constant is 29.8 s when input optical power is 73.8 mW. The finite element method was employed to estimate and correct the non-equivalence of the absolute radiometer. It indicates that the source of non-equivalence of SIAR mainly comes from the drifts driven by different heating paths and areas, and the correctional factor of non-equivalence for the SIAR is 0.999 621±0.000 004. The finite element correct model completes the correctional system of SIAR and significantly increases the accuracy of the SIAR. It is helpful to improve the future design of absolute radiometers.