FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

Technical Report · Fri Jul 01 04:00:00 EDT 2005

DOI:https://doi.org/10.2172/842719· OSTI ID:842719

Baker, Gregory L; Ghosh, Ruby N; Osborn, III, D J; Zhang, Po

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 {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Two critical materials issues are the cluster's 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 (K{sub 2}Mo{sub 6}Cl{sub 14}) 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 175 C 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.

• Research Organization: Michigan State University
• DOE Contract Number: FC26-02NT41582
• OSTI ID: 842719
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPOSITE MATERIALS
FIBER OPTICS
FIBERS
LIGHT EMITTING DIODES
LUMINESCENCE
MOLYBDENUM
MOLYBDENUM CHLORIDES
NITROGEN
OPTICAL FIBERS
OXYGEN
PERMEABILITY
POTASSIUM
POWER PLANTS