The counting of particles is likewise a cornerstone of biologic, chemical, medical and physical analysis methods. Generally, there is differentiation between particle-counter and single-particle-counter.
The standard measurements are via laser, either by light-diffraction, -scattering or -blocking.
Particle counts are from utmost importance in the manufacturing process of pharmaceutical products just as in the inspection of cleanness of industrial processes and products.
Systems for the particle count determination: