a method and device of detecting a scattering light beam for tools measuring scattering signals produced by the interaction of solid microparticles , such as a biological cells moving with a high - intensity , focused light beam , capable of reducing the influence of the cell movement with respect to the optical axis of the illuminating beam , and improving the quality of the signal characterized by the recognition of the individual particle or cell , specifically in fluid currents , such as those used in flow cytometry are disclosed .