Possible Use of Two Laser Beams to Determine Particle-Size Distribution.
Abstract
A study was made to determine whether particle-size distributions for small diameter aerosols (radius < or = 20 microns) such as fog can be determined by a new technique based on resonantly distorting the liquid drops by an oscillating electric field at the drops' mechanical vibrational frequencies. This field was transmitted by a linearly polarized CO2 laser of intensity 100 W/sq. cm. amplitude modulated at frequencies between 40,000 and 3,000,000 Hz, which correspond to the fundamental vibration frequencies of drops varying in radius from 21.2 to 1.19 microns. An unmodulated, 2-mW He-Ne laser was beamed along the path of the CO2 radiation, and scattering of this light was observed. The intensity of the He-Ne light scattered from the drops at the resonance frequency should be proportional to the density of the drops in the fog that oscillate at that frequency. A sensitive detection system able to measure ac signals with intensities as low as 10 to the -17th power W collected the scattered He-Ne light.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1979
- Accession Number
- ADA070965
Entities
People
- Donald E. Wortman
Organizations
- Harry Diamond Laboratories