FOURIER-TRANSFORM RADIATION THERMOMETRY - MEASUREMENTS AND UNCERTAINTIES

A Fourier-transform radiometer is used to measure blackbody temperatur es in the 500-1000-K range. The measurements involve collecting mid-in frared spectra at two known reference temperatures and one unknown tem perature. The accuracy of the interpolation measurement technique is d iscussed, and the effects of the uncertainty in the temperature refere nce points, the voltage ratio measurement, and the wavelength accuracy are described. Temperature accuracy at the 0.5% level has been achiev ed; the main uncertainty component is caused by the interferometer dri ft. Directions to reach 100-mk accuracy levels have been identified.