Patent ID: 8040508

Claim:
An apparatus for measuring an average mass concentration of a polydispersed agglomerate of primary particles, the apparatus comprising: a first light source configured to emit a first beam of light in a first direction said first beam of light having a first wave length; a light detector configured to generate a signal related to light scattered onto the light detector by the polydispersed agglomerate in a first probe volume formed in the first beam of light; and a calculating device to calculate the average mass concentration of the polydispersed agglomerate of primary particles based at least in part on the signal generated by the light detector, wherein the calculating device is configured to calculate a C m #(qd go ) and an average mass concentration of the polydispersed agglomerate, C m , per unit total scattered light, P Tθ , based on an equation given by: C m P T ⁢ ⁢ θ = f 1 ⁢ f 2 ⁢ C m ⁢ # ⁢ ( qd go ) , where f 1 is a function of optical properties of the primary particles, f 2 is a function of a configuration of the apparatus, q is a scattering wave vector at a mean scattering angle, θ, for the optical receiver element given, in terms of the first wave length, by (4π/λ)sin(θ/2), and d go is an average gyration diameter for an assumed size distribution for the polydispersed agglomerate.