No.3（2008）9.Development of a Far-Infrared Spectral Irradiance Measurement Method

Toshiharu Nakajima, Tetsuo Yamamoto, Toshihide Iwanaga, Hirotaka Nakamura

We investigated development of a method measure far-infrared spectral irradiance. The experimental system combined and built a Fourier transform infrared spectrometer (FTIR) and integrating sphere coated with gold. We removed the influence of normal temperature radiation from the output (the blackbody furnace and far-infrared heater) of FTIR, and corrected it. Then we sought the spectral irradiance of the blackbody furnace, to correct the experimental system. We found the spectral irradiance (the actual measurement) of the far-infrared heater from the spectral irradiance of the blackbody furnace, and the output of corrected FTIR. We found the spectral irradiance (the theoretical value) of the far-infrared heater from the arithmetic expression of illumination by direct light. We did comparative examination of the actual measurement and the theoretical value. If the distance was within 10 to 25cm at 2 to 15 microns in the wavelength range using the experimental system, we found it possible to measure spectral irradiance for the far-infrared heater with comparatively small exothermic capacity.

Keywords

far-infrared, spectral infrared irradiance, spectral emissivity, blackbody, Fourier transform infrared spectrometer

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