Laser Diffraction Spectrometer HORIBA LA-950 for analysing particle size distribution

Measurement Principle: Light scattering analysis using Mie Theory according to DIN/ISO 13320
Measuring Range
: 0,01 µm - 3000 µm
Type of analysis: wet measurement

A sample that passes a laser beam scatters the light at an angle and intensity that is directly related to the size of the particles:

  • Smaller particles scatter light with low intensity at wide angles.
  • Larger particles scatter light with higher intensity at narrow angles.

The measurement of the intensity of the diffracted light as a function of the angle and the processing of the data via a mathematical model allows calculating the particle size distribution of the sample.



The research group Geoecology uses the instrument for determining the grain size distribution of sediments and soil samples. Where applicable, the samples should be pretreated with hydrochloric acid for breaking down of carbonates and/or with hydrogen peroxide for oxidising organic compounds. To disperse the clay fraction of a sample completely, the clay minerals have to be covered with lyophilic cations (overhead shaking with Na-Polyphosphate).

Contact person: Elke Ahrensfeld