Laser granulometry: rapid and precise analysis of particle size
Laser particle size analysis is an analytical 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 for rapid, reproducible, and non-destructive measurement across a wide size range, from nanometers to millimeters . It is a reference method in the powders, cosmetics, materials, nutrition, food processing, pharmaceutical, and environmental sectors.
What is laser granulometry?
Laser granulometry , also called laser diffraction , is based on a simple physical principle: when a 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 post: Laser particle size analysis: laboratory results
How laser particle size analysis 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's model : more precise, applicable to a wide range of sizes and materials
The results are expressed in the form of:
- Particle size distribution curve
- Typical diameters: D10, D50, D90
- Average volumetric, surface or numerical values
Technical characteristics of laser particle size analysis
- Measurement 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
