Laserdiffraktiomenetelmien

Laserdiffraktiomenetelmät, often translated as laser diffraction methods, refer to a group of analytical techniques that utilize the phenomenon of light diffraction to determine the size distribution of particles in a sample. This method is widely employed in various scientific and industrial fields, including pharmaceuticals, chemistry, materials science, and environmental monitoring.

The fundamental principle behind laser diffraction lies in the scattering of laser light by particles suspended in a liquid or gas. When a beam of monochromatic light, such as that from a laser, encounters a particle, it is diffracted in all directions. The angle at which the light is scattered is inversely proportional to the size of the particle. Larger particles diffract light at smaller angles, while smaller particles diffract light at larger angles.

A typical laser diffraction instrument consists of a laser source, a sample dispersion unit, and a detector array. The sample is usually dispersed in a liquid medium, such as water or a suitable solvent, to ensure that particles are individually interacting with the laser beam. The dispersed sample then passes through the laser beam. The diffracted light is collected by a series of detectors positioned at various angles. These detectors measure the intensity of the scattered light at each angle.

Sophisticated optical models, such as the Mie theory, are then applied to the measured diffraction pattern to calculate the particle size distribution. The Mie theory accounts for the wavelength of the light, the refractive indices of both the particles and the dispersion medium, and the angular scattering pattern. The output of a laser diffraction analysis is typically a histogram or a cumulative distribution curve representing the proportion of particles within different size ranges. This provides valuable information about the average particle size, as well as the spread or uniformity of the particle population.