LOAC (Light Optical Aerosol Counter)
Measurements at 2 scattering angles (field of view of few degrees) : 
~12°, insensitive to the refractive index of the particles
(mainly diffraction) 

=> accurate size determination and counting 
~60°, strongly sensitive to the refractive index of the particles 
=> indication of the typology of the particles
Detection of the maximum of intensity for particle that crosses the laser beam 
Real-time stray light correction