Measuring and testing – Gas analysis – By vibration
Patent
1994-03-24
1995-08-29
Williams, Hezron E.
Measuring and testing
Gas analysis
By vibration
73 2401, 422 88, G01N 2700
Patent
active
054450080
ABSTRACT:
A mass microsensor is fabricated with a microcantilever oscillated by a piezoelectric transducer. A chemical coating having absorptive or adsorptive affinity for a specifically targeted chemical or compound is applied to the microcantilever for oscillation in the monitored atmosphere. Molecules of the targeted chemical attach to the microcantilever coating resulting in an oscillating mass increase which influences the resonant frequency of the microcantilever oscillation. The rate at which the coated microcantilever accumulates the target chemical is functional of the target chemical concentration. Consequently, the extent of microcantilever oscillation frequency change is related to the concentration of the target chemical within the monitored atmosphere. Such oscillation frequency changes are detected by a center-crossing photodiode which responds to a laser diode beam reflected from the microcantilever surface resulting in an output frequency from the photodiode that is synchronous with the microcantilever frequency.
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Thundat Thomas G.
Wachter Eric A.
Adams Harold W.
Brock Michael J.
Marcontell W. Allen
Martin Marietta Energy Systems Inc.
Spicer James M.
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