Mass Sensing with Damped Cantilever Beams

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There are a range of applications which require the identification of the component molecules of gasses and fluids. These range from fluid purity or contamination sensors in pipes and tanks to atmospheric probes on satellites and probes. There are two dominant methods currently utilised, photo-spectrometry and mass spectroscopy. The former uses imaging systems to identify the light spectrum absorption of known molecules when exposed to light while the latter uses electrical ionisation and electro-magnets to identify the masses of every molecule in a sample and predict the likely molecules present. However, it has also been theorised that a vibrating cantilever beam, damped or undamped, can be utilised to detect the mass of any attached object by comparing the resonance frequencies of the plain beam against those of the same beam with the attached mass. By exposing a fluid or gas sample to a sufficiently small, oscillating cantilever beam, some of the component molecules will temporarily adhere to the beam and act as an attached mass. The shifts in resonance frequency caused by this adhesion would be useable to determine the mass and thus identity of the molecules. To date researchers have proposed equations and methods which would function in one and two dimensions.