Laser granulometry: fast and precise analysis of particle size
Laser particle size analysis is an analysis technique used to measure the size and distribution of solid or liquid particles present in a sample. Based on the principle of light diffraction , it allows rapid, reproducible and non-destructive measurement, with a wide range of sizes from nanometers to millimeters . It is a reference method in the powder, cosmetics, materials, nutrition, food, pharmaceutical and environmental sectors.
What is laser granulometry?
Laser granulometry , also called laser diffraction , is based on a simple physical principle: when laser beam passes through a sample containing particles, these scatter the light at an angle inversely proportional to their size.
Small particles scatter light at large angles , while large particles scatter at small angles . By analyzing the angular distribution of this diffracted light, it is possible to reconstruct the particle size distribution of the sample, usually expressed as D10, D50 and D90.
To learn more, check out our blog article: Laser granulometry analyses: laboratory results
How laser granulometry works
The sample is dispersed either in a liquid (wet dispersion) or in an air stream (dry dispersion), then passed through by a laser beam . A detector measures the intensity of the diffracted light at different angles.
The data is then processed using mathematical models :
- Fraunhofer model : used for opaque particles > 10 µm
- Mie model : more accurate, applicable to a wide range of sizes and materials
The results are expressed as:
- Particle size distribution curve
- Characteristic diameters D10, D50, D90
- Volumetric, surface or numerical average values
Technical characteristics of laser granulometry
- Measuring range : approximately 10 nm to 3 mm depending on the equipment
- Rapid analysis : results in less than 2 minutes
- High reproducibility and precision
- Non-destructive method
- Compatible with dry or wet dispersion
- Applicable standards : ISO 13320, USP 429, EP 2.9.31, ISO 9276
For which matrices?
Main industrial applications
Léa Géréec
Technical and scientific advisor
