A technique for measuring the emissivity of single, nominally 50-µm-sized tungsten particles at elevated temperatures is demonstrated. Single particles are electrodynamically suspended in the cavity of a cw Nd:YAG laser and subsequently heated by the laser beam. The light emitted by the heated particles is focused onto the slit of a spectrometer. The detector used is an intensified gatable diode array that allows for the collection of time-resolved spectral data. Spectral radiance is deduced by calibrating the system against a standard lamp. Assuming that the relationship between emissivity and wavelength is a smooth function, the particle temperature and emissivity are determined by a curve-fitting procedure involving Planck's spectral radiation law. Experimental demonstration and error estimates of the technique are presented.
J. R. Fincke,
C. L. Jeffery,
R. Erik Spjut,
"Measurement Of The Emissivity Of Small Particles At Elevated Temperatures," Optical Engineering 27(8), 278684 (1 August 1988). https://doi.org/10.1117/12.7976741