1. n. [Formation Evaluation]

A technique for analyzing the grain-size distribution of a core sample. A cleaned, disaggregated sample is dispersed in a carrier fluid. The grains cause diffraction of a laser beam directed through the fluid. The angle of scattering is inversely proportional to the particle size, while the intensity of scattering is proportional to the number of particles. Laser diffraction also may be referred to as laser sieve analysis.

See: carrier fluid,  sieve analysis