Premium
Optical Particle Sizer: A New Development with Mathematical Correction of Spread Measurement Data
Author(s) -
Mühlenweg Heike,
Weichert Reiner
Publication year - 1997
Publication title -
particle and particle systems characterization
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 56
eISSN - 1521-4117
pISSN - 0934-0866
DOI - 10.1002/ppsc.199700046
Subject(s) - amplitude , particle size distribution , calibration , computational physics , optics , physics , particle (ecology) , distribution function , fredholm integral equation , particle size , light scattering , scattering , mathematical analysis , integral equation , mathematics , chemistry , quantum mechanics , geology , oceanography
The development of an optical particle sizer for aerosols is described which is based on the principle of light scattering by single particles. The instrument is appropriate for simultaneous measurements of broad particle size distributions and allows applications in hot gases. The main topic concerns the evaluation of the particle size distribution from measured data, i.e. a mathematical correction for the influence of inhomogeneous illumination and of particle shape. Irregularly shaped and randomly orientated particles which also might be illuminated inhomogeneously (laser light, border zone) deliver different signal amplitudes, which finally results in a spreading of the measured particle size distribution. Assuming a specific distribution of signal amplitudes related to every particle size and shape, the spreading of the measured data can be corrected. The mathematical procedure requires the solution of a Fredholm integral equation, i.e. the inversion of a linear equation set whose coefficients are based on a correction function to be determined by a preceding calibration. A new inversion method has been developed combining the well known regularizalion according to Phillips and Twomey and the non‐negative least‐squares method according to Lawson and Hanson.