Experimental validation of a pyroreflectometric method to determine the true temperature on opaque surface without hampering reflections

Optical properties of black and white ZrO2 for solar receiver applications

“…Similarly to what explained in [10], to allow a comparison with previous measurements, the socalled color temperature must be considered [27]. A discussion of the color and cross temperatures is beyond the scope of the present work and can be found in the literature [16,17,27]. Here it is worth to say that usually color temperature is slightly higher than cross temperature, thus the emittance calculated on the color temperature basis is slightly lower than the emittance calculated taking the cross temperature as reference.…”

“…The light detector was a radiometer sensitive to the 0.6-40 μm wavelength range, equipped with an optical telescope allowing to collect the light emitted by a small region near the center of the sample. The temperature of the sample surface was measured by a specifically developed two-color pyro-reflectometer [16,17], with operative wavelengths of 1.30 and 1.55 mm. Laser light at these wavelengths is transported with an optical fiber very close to the sample (3 mm), with quasi-normal incidence angle.…”

“…The experimental temperature is the pyro-reflectometric cross-temperature[16,17,27]. The emittance values calculated from Eq.…”

Efficiency and behavior of textured high emissivity metallic coatings at high temperature

“…The facility can be instrumented to perform the following measurements, all on the back face of the sample: temperature, directional total, or spectral, or in narrow ranges emissivity using a Heimann KT4 radiometer, mass spectrometry, and mass loss via a Quartz Crystal Microbalance. The temperature is measured with a bi-color optical fiber pyro-reflectometer developed at PROMES-CNRS [13]. Finally, tubes at 30°and 45°to the normal of the sample surface have been placed around the chamber to accommodate the treatment instruments: the Thermo-Fisher EX05 ion gun and the Omicron HIS13 VUV source (not used in this study).…”

“…This calibration is done in a way that the entire optical path of MEDIASE is reproduced on the calibration bench. The bi-color optical-fiber pyro-reflectometer is also calibrated, but because of its complex functioning [13], it requires two separate calibrations: one on a blackbody and one on a reflectivity calibration bench using reference reflectivity samples (Labsphere references). The bi-color optical-fiber pyro-reflectometer, in opposition to classical pyrometers, provides the real temperature of the surface without having to measure or assume first an emissivity or use the gray-body hypothesis: by measuring simultaneously the reflectivity and the radiance of the sample at two wavelengths (1.3 and 1.55 lm), it provides the real surface temperature without knowledge of the emissivity.…”