HIGH-TEMPERATURE REMOTE THERMOMETRY USING LASER-INDUCED FLUORESCENCE DECAY LIFETIME MEASUREMENTS OF Y2O3-EU AND YAG-TB THERMOGRAPHIC PHOSPHORS

A Nd: YAG laser-based remote sensing system, for determining the surfa ce temperature of substrates coated with thermographic phosphors, has been developed. The obtained fluorescence decay lifetime versus temper ature measurements for Y2O3: Eu (4.52% Eu) and YAG: Tb (5% Tb) over th e temperature range 27-1095-degrees-C are presented. Both phosphors ca n be used for continuous temperature measurements over the range appro ximately 550-degrees-C- approximately 1000-degrees-C. In addition, ste pwise regression analysis is used to calculate empirical relationships expressing temperature as a function of the measured fluorescence lif etimes for both phosphors beyond the onset temperature quenching point . The accuracy of the temperature measurements was estimated to be +/- 5%. Furthermore, a comparison between the intensity of the 611 nM-Y2O 3: Eu and the 544 nm-YAG: Tb emission lines as a function of temperatu re is presented.