Laser Particle Size Analysis consists in measuring the size of particles (powders, suspensions and emulsions) using the diffraction and diffusion of a laser beam.
Two theories are used depending on the size of the particles :
--> Fraunhofer Theory (diffraction) 

• 1969 

CILAS is the inventor of the first particle size analyzer driver, by the cement industry.
• 1972 First system 220 (2.5 - 100 µm)
• 1978 Model 227 (0.5 - 128 µm)
• 1979 Model 715 (0.5 - 192 µm)
• 1985 Model 850, sub micron capability (0.1 - 600 µm) 
• 1992 Model 1064 (0.04 - 500 µm) & auto sampler
• 1993 Dry mode
• 1994 Small volume unit
• 1995 Model 940 (0.5 - 2000 µm)
• 1996 Software "The Particle Expert" under Windowsô
• 1998 Model 1180 (0.04 -2500 µm)
• 2000 Free fall