Solar blind pyrometry not relying on atmospheric absorption bands

• We developed a method to measure temperature with an IR camera in solar furnaces.
• Reflected solar radiation is a problem we solve by using two band pass filters.
• Filters centered in atmospheric transmission bands reduce the uncertainty sources.
• One filter allows the camera to measure the temperature through quartz windows.
• The other one allows measuring the temperature of the window.

Infrared measurement of the thermal radiation emitted by solar irradiated material surfaces is the most reliable alternative to contact thermometry which is inadequate for measuring surface temperatures. However, reflected solar radiation and the use of windows for material testing in controlled atmosphere or vacuum, can be important sources of error in this non-contact methodology. A promising method for eliminating this solar perturbation is by using centered band-pass filters on the spectral bands where the solar radiation has been attenuated. Two wavelength bands are analyzed in this paper. An IR camera prototype with band-pass filters centered at these two wavelength bands and an analysis of its behavior are presented.