Fast determination of the particle size of aerosols and hydrosols by measuring the attenuation of sonic waves

The attenuation of a sonic wave, passing through an aerosol, is caused by the mechanical interaction of the particles with the surrounding gas and other effects. The theory for this leads to an integral relation between the frequency dependent attenuation coefficient and the propability density function N(r) of the particle radius. With a fast inversion method for the arising Fredholm integral equation a fast possibility for the determination of the particle number distribution from 10 sonic attenuation measurements in the size range of 0.1μm to 10μm is shown.