Photodetection of low level phosphorescence produced by low level oxygen concentrations using optical system based on fiber optical and avalanche photodiode

In this paper, a very simple and low-cost photodetection system is presented which can be used for measuring very low oxygen concentration in gaseous medium based on phosphorescence lifetime of Al-ferron in sol-gel probe. A similar system has been presented but the most innovative aspect in this work is in the use of avalanche photodiode (APD). APD has several important advantages over photomultiplier tubes (PMTs) such as a lower device size, low cost and less critical power supply requirements. The APD also has a good photosensitivity and low dark current, enough characteristics for measuring phosphorescence. So, this kind of device becomes very interesting for use in phosphorimetric systems.