Temperature measurements of high-temperature surface in environments with interfering radiation using luminescence lifetime thermometry

Abstract

Interfering radiation, such as self-emitting thermal radiation, infrared radiation from heating sources, and combustion gas radiation, significantly impacts the use of optical thermometry. How to improve the precision of temperature measurement in such an environment is a key issue. Therefore, this work aimed to quantitatively analyze the temperature measurement precision of luminescence lifetime thermometry for measuring the temperatures of hot components in environments with interfering radiation. In this paper, based on the quantitative analysis of measurement noise of optical signal and the error propagation theory, we proposed a theoretical model for predicting the temperature measurement precision of luminescence lifetime thermometry. Using blue LED as the interfering radiation source, the temperature measurement experiments of high-temperature surfaces under different interfering radiation intensities were carried out. By comparing the measured precision based on the standard deviation of repeated experiments with the predicted precision of the theoretical model proposed in this paper, the reliability of this theoretical model was verified. The experiments also revealed that the temperature measurement precision was linearly related to the square root of the measured signal intensity (i.e., the sum of luminescence signal and interfering radiation signal). With the increase of the background interfering radiation intensity, although the accuracy of temperature measurement did not change significantly, the measurement noise increases, resulting in a significant increase in random error of measured temperature. This work provides guidance for developing luminescence lifetime thermometers and their applications in environments with interfering radiation.