The Mastersizer laser diffraction particle size analyzer is used to determine accurate particle size distributions for both wet and dry dispersions.
During a laser diffraction measurement a laser beam passes through a dispersed particulate sample and the angular variation in intensity of the scattered light is measured. Large particles scatter light at small angles relative to the laser beam and small particles scatter light at large angles. The angular scattering intensity data is then analyzed to calculate the size of the particles that created the scattering pattern using the Mie theory of light scattering. The particle size is reported as a volume equivalent sphere diameter.
Figure 1. Schematic showing scattering angles in relation to particle size (image:MalvernPanalytical).
In house: MalvernPanalytical Mastersizer Hydro 2000 & Hydro 2000 S
- Principle: Laser light scattering
- Analysis: Mie and Fraunhofer scattering
- Data acquisition rate: 1 kHz
- Red light source: Max. 4mW He-Ne, 632.8nm
- Blue light source: Max. 0.3mW LED, 470nm
- Lens arrangement: Reverse Fourier (convergent beam)
- Particle size: 0.02 - 2000 µm *
- Accuracy: Better than 1% (polydisperse standard) **
- Reproducibility: Better than 1% variation (polydisperse standard)