Open AccessFiber Optical Micro-detectors for Oxygen Sensing in Power Plants
Author(s) -
Gregory L. Baker,
Ruby N. Ghosh,
III Osborn,
Po Zhang
Publication year - 2006
Language(s) - English
Resource type - Reports
DOI - 10.2172/876615
Subject(s) - molybdenum , quenching (fluorescence) , optical fiber , oxygen sensor , fiber optic sensor , materials science , fiber , analytical chemistry (journal) , oxygen , chloride , optoelectronics , chemistry , optics , composite material , metallurgy , fluorescence , physics , organic chemistry , chromatography
A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Previously we described a particle-in-binder approach to immobilizing the potassium salt of a molybdenum cluster, K{sub 2}Mo{sub 6}Cl{sub 14}, at the tips of optical fibers. Compared to previous methods, the particle-in-binder approach affords fibers with greatly improved mechanical properties. We have extensively characterized two fiber sensors at high temperature. We obtain quenching ratios between pure nitrogen and 21% oxygen as high as 3.9 x at 70 C. For the first sensor at 60 C we obtained a {+-} 1% variation in the quenching ratio over 6 cycles of measurement, and monitored the device performance over 23 days. We were able to operate the second sensor continuously for 14 hours at 70 C, and the sensor quenching ratio was stable to 5% over that time period. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters