A Simple Fiber Optic Temperature Sensor for Fire Detection in Hazardous Environment Based on Differential Time Rise/Decay Phosphorescence Response

In the present article, we report the development of a simple temperature sensor based on the difference in the temperature dependences of the rise and decay time and the intensity responses of Eu2+, Dy3+-doped strontium aluminates. A 374-nm pulsed LED was used as a UV source in combination with a lead-in and -out optical fiber to excite the sample and capture the phosphorescence. We show that because of the power law rise and decay time responses, the differential signals measured at earlier instants exhibit the highest sensitivities to temperature over the range from about 5 degrees C to 95 degrees C. Normalized differential signals are characterized by a wide range of linear responses to temperature changes, sensitivity of up to approximate to-1.89%/degrees C, and a relative error of less than 0.5%. Application to fire prevention is discussed and argumented.