中红外大气背景辐射测量系统及误差分析

Measurement System and Error Analysis of Mid-Infrared Atmospheric Background Radiation

为研究大气背景辐射和仪器辐射规律、控制仪器热辐射和仪器精度,设计了一套大气背景辐射测量系统。分析了测量系统各组件和辐射定标等各类误差源对总测量误差的影响,还分析了定标精度的影响因素,确定了测量工作的改进方向。结果表明:该系统在定标区间内的测量误差主要是定标误差和随机误差,两者分别为2.4719%和0.0790%;合成误差为2.4732%。当用该系统测量大气背景辐射时,对大多数优良的天文台站而言,大气辐射强度远低于定标时的辐射强度,因此需进行外推测量。对外推测量误差的估计结果表明,外推测量可能导致较大的测量误差。为提高大气背景辐射测量精度,更低辐射强度的标准辐射源不可或缺。研制了大气背景辐射测量系统,并进行了野外实测等工作,这为大口径红外天文望远镜系统的研制并将其实际应用于红外天文观测提供了基础。

To investigate the laws of atmospheric background radiation and instrument radiation as well as control the instrument thermal radiation and instrument accuracy,a measurement system of atmospheric background radiation is designed.The effects of various error sources,such as each component of this measurement system and radiation calibration,on the total measurement error are analyzed.Meanwhile,the factors influencing the accuracy of calibration are also analyzed.Finally,the direction of improving the measurement work is determined.These results show that the measurement error of this system in the calibration region is mainly composed of the radiometric calibration error and random error,whose values are 2.4719%and 0.0790%,respectively.In addition,the composite error is 2.4732%.For most of excellent astronomy sites,the atmospheric radiation intensity is far lower than the calibration value,and thus the extrapolation measurement is unavoidable.The estimation results of the extrapolation measurement errors indicate that the extrapolation measurement can lead to relatively high measurement errors.Therefore,in order to improve the precision of atmospheric background radiation measurement,the standard radiation sources with low radiation intensity are indispensable.The development of the atmospheric background radiation measurement system and the measurement work in the field are helpful to experience accumulation for the further development of large aperture infrared astronomical telescope systems and their practical applications to infrared astronomical observations.