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Proceedings Paper

Double integrating sphere system for optical parameter determination of industrial suspensions
Author(s): Ville T. J. Keränen; Anssi J. Mäkynen
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Paper Abstract

The main objective of this study was to construct a double integrating sphere system and to verify its performance using Intralipid fat emulsion. The final goal was to be able to determine optical properties of various turbid suspensions with the proposed system. Online measurements even would have been possible as backscattering and forward scattering were measured simultaneously. The measured suspension was injected in a cuvette placed between two integrating spheres and illuminated with a laser through the first sphere. The diameter of the spheres was 8" and the diameter of the sample port could have been varied up to 2.5". The cuvette was made of plastic and optical grade glass and its diameter was sufficient to cover the sample port area. The sample thickness in the measurement cuvette was 5 mm. Optical powers were detected using fiber coupled photodiodes. There was one diode for each sphere and one for the unscattered light at the opposite end of the sphere system facing towards the laser. The measured optical powers were converted to absorption coefficient, scattering coefficient and if possible to anisotropy using an inverse adding-doubling method. The results measured for the Intralipid using the described system corresponded with those documented in published literature. A number of pulp samples with unknown optical properties were measured with encouraging results. However, the differences between different pulps and fillers are so small that, in the future, the focus will be in error source elimination to achieve reasonable accuracy.

Paper Details

Date Published: 5 June 2008
PDF: 8 pages
Proc. SPIE 7022, Advanced Laser Technologies 2007, 70220T (5 June 2008); doi: 10.1117/12.804056
Show Author Affiliations
Ville T. J. Keränen, Univ. of Oulu (Finland)
Anssi J. Mäkynen, Univ. of Oulu (Finland)


Published in SPIE Proceedings Vol. 7022:
Advanced Laser Technologies 2007

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