Development of an Automated Fiber Counting Instrument.
NIOSH 1979 Aug:45 pages
A prototype automated fiber counting instrument capable of discriminating between fibrous and nonfibrous particles deposited on cleared membrane filters was developed. Fiber recognition was accomplished by focusing a helium neon laser beam on an area approximately 20 micrometers in diameter, scanning the resulting diffraction pattern with an analog optical mask, and analyzing the resulting electrical signal. A four zone slit mask with radial openings every 90 degrees was used as the diffraction plane filter mechanism. A modulation value of length between 0.5 and 0.6 micrometers defined the fiber classification boundary. Data processing was performed utilizing a digital electronic microprocessor. The authors conclude that the optical configuration of the equipment developed is marginal for commercial use in identifying fibers less than 1 micrometer in length.
NIOSH-Contract; Contract-210-77-0067; Fibrous-bodies; Analytical-methods; Analytical-instruments; Analytical-processes; Particle-counters;
NTIS Accession No.
NIOSH, U.S. Department of H.E.W., Cincinnati, Ohio, 45 pages