Temperature and Thickness Dependence of IR Optical Properties of Sapphire at Moderate Temperature

Lee, Geun Woo; Jeon, Seol; Park, Seung-Nam; Yoo, Yong Shim; Park, Chul-Woong

doi:10.1007/s10765-011-0990-2

Cited by 14 publications

(3 citation statements)

References 9 publications

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“…Thus, two additional sources need to be included in the uncertainty calculations and all partial derivatives evaluated in section 4 need to take into account an additional weight of (1 + (1 − ε sub )τ ) −1 . The transmittance is evaluated as a Type B uncertainty from extreme values taken from literature data [63], whereas the emissivity of ARMCO iron and its combined standard uncertainty have been evaluated in our laboratory.…”

Section: Combined Standard Uncertainty Of Representative Materialsmentioning

confidence: 99%

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Updated measurement method and uncertainty budget for direct emissivity measurements at the University of the Basque Country

Arrieta¹,

Echániz²,

Fuente³

et al. 2020

Metrologia

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This work reports on the upgrades made to the direct emissivity measurement facility of the UPV/EHU. The instrumental improvements consist of, among others, a high-vacuum system and wider temperature range (300 − 1273 K). Methodological developments include a refined measurement equation with updated parameters and a reworked ISO-compliant uncertainty budget, and a Monte Carlo procedure for accurate calculations of total emissivities from spectral data. These upgrades have been demonstrated and validated in measurements of both metallic and ceramic materials. The results obtained in this work are applicable to similar experimental devices for emissivity measurements in order to report reliable emissivity data.

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Section: Combined Standard Uncertainty Of Representative Materialsmentioning

confidence: 99%

“…In order to check the validity of the applied method and the calculated uncertainties, a comparison to literature data from reference [63] has been made in figure 6. There is quantitative agreement between both curves in certain wavelength ranges, although some discrepancies may be noted.…”

Section: Combined Standard Uncertainty Of Representative Materialsmentioning

confidence: 99%

Updated measurement method and uncertainty budget for direct emissivity measurements at the University of the Basque Country

Arrieta¹,

Echániz²,

Fuente³

et al. 2020

Metrologia

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“…The transmittance and the reflectance of the window with a thickness of 2 mm and a diameter of 50 mm were measured by using an IR spectrometer (Nicolet 6700). The We present the measuring method and the sample heater in a separate paper [6]. Figure 5 shows the emissivity of a UV-grade sapphire window for various temperatures from 30 • C to 500 • C, which is deduced from the transmittance and reflectance.…”

Section: Emissivity Of a Sapphire Window At Elevated Temperaturesmentioning

confidence: 99%

Thermal Image Degradation Through a Heated Sapphire Window

et al. 2011

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Optical windows are indispensable for monitoring industrial processes under vacuum or high pressure by using thermal imagers and radiation thermometers. When a thermal imager observes a sample through an infrared window at elevated temperatures, the window emits additional thermal radiation and increases the background signal of the thermal images, which results in image degradation. Standard four-bar images with various radiance temperature differences were measured using a thermal imager with a spectral band from 3 µm to 5 µm through a UV-grade sapphire window. The four-bar images are given by a blackbody collimator with various image patterns. The window was indirectly heated in a furnace and then rapidly placed on the optical path between the collimator and the thermal imager. The four-bar image degradation was measured as a function of the window temperature and the radiance temperature difference of the four-bar pattern. A simple equation which describes the contrast of the four-bar image by using the transmittance and reflectance of the sapphire window was proposed. It was confirmed that the model can properly predict the window temperature when the appearance of the four-bar pattern cannot be determined.Keywords Aerodynamic heating · Emissivity · Infrared window · Minimum resolvable temperature difference (MRTD) · Noise equivalent temperature difference (NETD) · Thermal imager

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Difference of optical properties between porous alumina and sapphire using two-substrate method at elevated temperature

Jeon

Kang

Lee

2013

Current Applied Physics

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Temperature and Thickness Dependence of IR Optical Properties of Sapphire at Moderate Temperature

Cited by 14 publications

References 9 publications

Updated measurement method and uncertainty budget for direct emissivity measurements at the University of the Basque Country

Updated measurement method and uncertainty budget for direct emissivity measurements at the University of the Basque Country

Thermal Image Degradation Through a Heated Sapphire Window

Difference of optical properties between porous alumina and sapphire using two-substrate method at elevated temperature

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