Measurement of low oxygen concentrations by phosphorescence lifetime usingoptical fibers

In this paper, a relatively simple, low-cost industrial prototype for measu ring low oxygen concentrations in gaseous medium based on phosphorescence l ifetime of Al-Ferron in Sol-Gel probe is presented. The main advantages ove r other techniques are an excellent sensitivity, precision, selectivity, re sponse time, and facility of maintenance. Fiber optics is used to guide the light. This fact allows one to reach difficult places and to make the meas urements from a distance. The design of the system and best ways to maximiz e the emission maximizing the excitation light from the light source, the o ptimal distance from the optical fibers to the chemical sensor, and a simpl e method to filter the response are discussed and verified with the prototy pe developed. The system allows the detection of oxygen concentrations of 0 .005%.