Spatial marks shaping techniques in counting volume

There have been developed and applied four methods of spatial marks shaping in counting volume of photoelectric aerosol particle counters. For example, in order to make measurements in optical dense aerosols we have developed the techniques to shape the counting volume of minimum possible dimensions by means of two counter-current convergent coherent laser beams. Focusing a fan of different wavelength divergent monochromatic beams in counting volume one can form a virtual ruler that will allow to directly define an aerosol particle size.