USGS-GD-Scientific Capabilities  - GRAIN SIZE ANALYZER Equipment



  • Malvern Laser-Diffraction Particle Size Analyzer (Laser PSA) was purchased in 1997. The Laser PSA is a fully automated instrument for measuring the particle size distribution of sediment samples. The Malvern laser PSA occupies the top of a laboratory bench and is connected to a water supply. Dispersed samples are suspended in a volume of water that is circulated rapidly, in constant agitation so that all grain sizes are randomly distributed, as the laser beam samples the passing grains. The laser PSA is attached to a computer with software that permits instantaneous display of results as numbers and graphs, export of results to spreadsheet program such as Excel, and is flexible in reporting particle-size data in several modes including phi units, Wentworth, USDA, or a user-specified set of sizes. The instrument is located in Denver.

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