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一、前言航天及航空技术中所用传感器离不开光谱辐射亮度的定标,特别是飞行前传感器的定标与试验结果的处理。用国家级绝对辐射计标定两种黑体的Stefan-Boltzman 常数与理论值最大偏差为2%,该偏差表示了绝对黑体所期望的可置信度。黑体B 即使在负载波动很大时,也具有保持均温的自调能力,特别适用于2.5～15.0 μm 系统光谱定标。由于限制光阑半径r_(max)使L/r_(max)=12.5,用Gouffé公式算出ε>0.999[1],定标结果足够令人满意。二、黑体A 的结构及设计考虑图1为黑体A 的构造,其外形φ18×28 cm,孔径φ2～φ8±0.002 mm,中空的隔热套与相当厚的绝热层足以保证绝热性。绕在传热铜管上的加热绕组提供升温到设定值的热能。三只高精度铂电阻对称地镶入黑体腔体内,一只控温,一只保护、报警,另一只精确地测定腔室的即时温度。
I. Introduction The sensors used in aerospace and aeronautical technology are inseparable from the calibration of spectral radiance, especially the calibration of pre-flight sensors and the processing of test results. The maximum deviation of the Stefan-Boltzman constants of the two blackbodies from the theoretical value is 2%, which is indicated by the national absolute radiometer. This deviation represents the confidence that the absolute blackbody expected. Blackbody B has self-tuning capability to maintain a uniform temperature even with large load fluctuations, and is especially suitable for spectral calibration of systems from 2.5 to 15.0 μm. The calibration result is satisfactory because the limiting aperture r_ (max) makes L / r_ (max) = 12.5, and the Gouffé formula calculates ε> 0.999 [1]. Structure and Design Considerations of Blackbody A Figure 1 shows the structure of blackbody A with the shape of φ18 × 28 cm and the diameter of φ2 ~ φ8 ± 0.002 mm. The hollow insulation sleeve and the thick insulating layer are enough to ensure the heat insulation. The heated winding wound around the heat transfer brass provides the thermal energy that is warmed up to the set value. Three high-precision platinum resistance symmetrically embedded in the black body cavity, a temperature control, a protection, alarm, and the other one to accurately measure the chamber’s real-time temperature.