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The spectral emissivities of silicon wafer, silicon carbide, molybdenum and tungsten at different wavelengths and temperatures. (a) Silicon wafer, (b) Silicon carbide, (c) Molybdenum, (d) Tungsten
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A measurement apparatus based on the optical fiber spectrometer is established to measure the directional spectral emissivity in the near infrared band. The sample is heated by a self-designed silicon carbide heater. The measurement angle can be adjusted from 0° to 82° by rotating the fiber collimating lens installed in a motorized rotary stage. Th...
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... stability and reliability of the experimental device. The directional spectral emissivity of a singlesided polished silicon wafer with a resistivity of 1 Ω·cm is measured at 900 nm and 1000 K. The simulated data are calculated based on the Fresnel formula [26,27]. The experimental and simulated data of directional spectral emissivity are shown in Fig. 4a together with the results in the literature [17]. It can be seen that the experimental and simulated data are almost coincident with the results of previous study in the measurement angle range from 0° to 82°. The deviation at measurement angle greater than 82° is related to the technical limitations including the measurement area ...Context 2
... and the inconsistency of the optical system, sample composition and environmental condition in different experiments [17,26]. The normal spectral emissivities of silicon carbide, molybdenum, and tungsten are measured in the verification experiment due to the lack of the directional spectral emissivity data in the near infrared. As shown in Fig. 4, it can be seen that the experimental data are almost coincident with those in the literatures [28,29], which indicates the good stability and reliability of the experimental ...Citations
To realize precise directional spectral emissivity determination of solid materials under the atmosphere, an apparatus what covers the temperature region from 50 °C to 1000 °C and a spectral range of 3 μm–14 μm was developed. The measurement angle can be adjusted from 0° to 60° utilizing a stepper rotary stage. The reliability of the apparatus’s reliability was confirmed by measuring the spectral emissivity of a SiC sample at high temperatures. Furthermore, the normal spectral emissivity of SiC was investigated from 50 °C to 1000 °C, and the directional spectral emissivity at 600 °C and 800 °C was shown. The influence of temperature and measurement angle on the spectral emissivity of SiC was analyzed in detail. Additionally, the cause of the silicon dioxide film on the surface of SiC after high temperature heating and its influence on spectral emissivity were explored. Finally, a detailed analysis of the uncertainty components of the emissivity measurement under varying temperatures and wavelengths was performed, and the results showed that the uncertainty of the apparatus was better than 0.05 in its measurement range.
This paper verified through experiments that change in ambient temperature are the main cause of dark output noise drift. Additionally, the impact of dark output noise drift in fiber optic spectrometers on emissivity measurements has been investigated in this work. Based on an improved fiber optic spectrometer, two methods were proposed for characterizing and correcting the dark output noise offset in fiber optic spectrometers: the mean correction scheme and the linear fitting correction scheme. Compared to the mean correction scheme, the linear fitting correction scheme is more effective in solving the problem of dark output noise drift. When the wavelength is greater than 1600 nm, the calibration relative error of silicon carbide (SIC) emissivity is less than 0.8% by the mean correction scheme, while the calibration relative error of silicon carbide emissivity is less than 0.62% by the linear fitting correction scheme. This work solves the problem of dark output noise drift in prolonged measurement based on fiber optic spectrometers, improving the accuracy and reliability of emissivity and quantitative radiation measurement.
