High accuracy hot spot size estimation technique for Raman Distributed Temperature Sensors

We report in this work for the first time, to the best of the author's knowledge, an approach that allows to accurately determine directly from the sensor response the hot spot size in Raman Distributed Temperature Sensors. Our method applies a linear regression model to the full width at half maximum response based on the correlation between the spatial and temperature measurements of the sensor. Measurements of hot spot sizes of only 5 cm were achieved with 98% precision for a commercial sensor with spatial resolution of 1 m. Moreover, for hot spots shorter than the sensor resolution this technique also allows improvements in the average accuracy of temperature measurements by up to 86%.