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Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants. (Quarterly Technical Report, April 1, 2005-June 30, 2005).

DE2005842719

Publication Date	2005
Personal Author	Baker, G. L.; Ghosh, R. N.; Osborn, D. J.
Page Count	40
Abstract	A reflection mode fiber optic oxygen sensor is being developed that can operate at high temperatures for power plant applications. The sensor is based on the 3O2 quenching of the red emission from hexanuclear molybdenum chloride clusters. Two critical materials issues are the clusters ability to withstand high temperatures when immobilized in a porous the sol-gel support, and whether after heating to high temperatures, the sol-gel matrix maintains a high and constant permeability to oxygen to support rapid quenching of luminescence. We used a composite materials approach to prepare stable sensing layers on optical fibers. We dispersed 60 w/w% of a pre-cured sol-gel composite containing the potassium salt of molybdenum clusters (K2Mo6Cl14) into a sol-gel binder solution, and established the conditions necessary for deposition of sol-gel films on optical fibers and planar substrates. The fiber sensor has an output signal of 5 nW when pumped with an inexpensive commercial 365 nm ultraviolet light emitting diode (LED). Quenching of the sensor signal by oxygen was observed up to a gas temperature of 175C with no degradation of the oxygen permeability of the composite after high temperature cycling. On planar substrates the cluster containing composite responds within <1 second to a gas exchange from nitrogen to oxygen, indicating the feasibility of real-time oxygen detection.
Keywords	Thermal power plants Oxygen sensors Fiber optics Luminescence Molybdenum chlorides Permeability Reflection Potassium chlorides Sol-gel processes
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Michigan State Univ., East Lansing. Dept. of Chemistry.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200605

Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants. (Quarterly Technical Report, April 1, 2005-June 30, 2005).

Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants. (Quarterly Technical Report, April 1, 2005-June 30, 2005).
DE2005842719

Publication Date	2005
Personal Author	Baker, G. L.; Ghosh, R. N.; Osborn, D. J.
Page Count	40
Abstract	A reflection mode fiber optic oxygen sensor is being developed that can operate at high temperatures for power plant applications. The sensor is based on the 3O2 quenching of the red emission from hexanuclear molybdenum chloride clusters. Two critical materials issues are the clusters ability to withstand high temperatures when immobilized in a porous the sol-gel support, and whether after heating to high temperatures, the sol-gel matrix maintains a high and constant permeability to oxygen to support rapid quenching of luminescence. We used a composite materials approach to prepare stable sensing layers on optical fibers. We dispersed 60 w/w% of a pre-cured sol-gel composite containing the potassium salt of molybdenum clusters (K2Mo6Cl14) into a sol-gel binder solution, and established the conditions necessary for deposition of sol-gel films on optical fibers and planar substrates. The fiber sensor has an output signal of 5 nW when pumped with an inexpensive commercial 365 nm ultraviolet light emitting diode (LED). Quenching of the sensor signal by oxygen was observed up to a gas temperature of 175C with no degradation of the oxygen permeability of the composite after high temperature cycling. On planar substrates the cluster containing composite responds within <1 second to a gas exchange from nitrogen to oxygen, indicating the feasibility of real-time oxygen detection.
Keywords	Thermal power plants Oxygen sensors Fiber optics Luminescence Molybdenum chlorides Permeability Reflection Potassium chlorides Sol-gel processes
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Michigan State Univ., East Lansing. Dept. of Chemistry.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200605