Discussion of line-start theory

Although equation (8.56) is the recommended one for the line-start technique [33] there is considerable disagreement as to whether it is correct and it is often assumed that the attenuation is proportional to 

The number fraction of particles in the field of view is given by  

Treasure assumed that the relative number concentration in the light beam, centered on d, may be expressed by the linear function n d, )-= f + g d i). I hus the total cross-sectional area of particles in the beam is proportional to  

The solution to this integral, if higher order terms are neglected, gives the proportionality  

Other published solutions state that the amount of light cut off is proportional to particle volume [34,35] for line-start and to particle surface for homogeneous mode. 

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