Optical Airborne Particle Counter Operation

  • Alvin Lieberman


For most cleanroom airborne particle measurements, an optical single particle counter (OPC) is used. An OPC measures particle size in response to the amount of light level change caused by the presence of a particle as it passes through a sensing zone within the OPC. The light level change can be positive or negative, depending upon the nature of the OPC. Three types of measurements are made with OPCs. Particles suspended in gas or liquid or on surfaces are measured. Particles can be counted and sized in ambient air or in either compressed or low-pressure gases with these devices. Particles can be measured in a variety of liquids, including those that are extremely corrosive. Particles can also be measured on surfaces that are actual product surfaces or surrogates of the product or of the cleanroom environment. The last procedure is used to indicate deposition upon critical surfaces that cannot be removed from the product area for testing purposes.


Particle Counter Sheath Flow Sensitive Zone Illumination Wavelength Illumination Beam 
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  1. Aitken, J., 1888. On the Number of Dust Particles in the Atmosphere. Proceedings of the Royal Society, Edinburgh, p. 35.Google Scholar
  2. Bartz, H., et al., 1985. Response Characteristics for Four Different Condensation Nucleus Counters to Particles in the 3-50 nm Diameter Range. Journal of Aerosol Science 16(5):443–456.CrossRefGoogle Scholar
  3. Borden, P., & Knodle, W., 1988. Monitoring Particles in Vacuum Equipment. Proceedings of the 9th International Committee of Contamination Control Societies Conference, pp. 204–207, September 26, 1988, Los Angeles.Google Scholar
  4. Borden, P., et al., 1989. Real-Time Monitoring of Large Particle Fallout for Aerospace Applications. Proceedings of the 35th Institute of Environmental Science Annual Technical Meeting, pp. 394–396, April 1989, Anaheim, CA.Google Scholar
  5. Bowling, R. A., Larrabee, G. B., & Fisher, W. G., 1989. Status and Needs of In-Situ Real-Time Process Particle Detection. Journal of Environmental Science 32(5):22–27.Google Scholar
  6. Cooke, D. D., & Kerker, M., 1975. Response Calculations for Light Scattering Aerosol Particle Counters. Applied Optics 14(3):734–739.CrossRefGoogle Scholar
  7. Ensor, D. S., & Donovan, R. P., 1985. The Application of Condensation Nuclei Monitors to Clean Rooms. Journal of Environmental Science 28(2): 34–36.Google Scholar
  8. Ensor, D. S.,et al., 1989. Measurement of Ultrafine Aerosol Particle Size Distributions at Low Concentrations by Parallel Arrays of a Diffusion Battery and a Condensation Nucleus Counter in Series. Journal of Aerosol Science 20(4): 471–475.CrossRefGoogle Scholar
  9. Fisher, M. A., et al., 1955. The Aerosoloscope: An Instrument for the Automatic Counting and Sizing of Aerosol Particles. Proceedings of the Third National Air Pollution Symposium, April 18–20, 1955, Pasadena, CA.Google Scholar
  10. Hayakawa, I., et al., 1984. Image Processing on Remote Detected Particulates in Clean Room. Proceedings of the 30th Institute of Environmental Science Annual Technical Meeting, pp. 90–93, May 1984, Orlando, FL.Google Scholar
  11. Hodkinson, J. R., & Greenfield, J. R., 1965. Response Calculations for Light Scattering Aerosol Counters. Applied Optics 4(1): 1463–1474.CrossRefGoogle Scholar
  12. Knollenberg, R. G., 1987. Sizing Particles at High Sensitivity in High Molecular Scattering Environments. Proceedings of the 34th Institute of Environmental Science Annual Technical Meeting, May 1987, King of Prussia, PA.Google Scholar
  13. Lieberman, A., 1988. A New 0.05 μm, 0.1 CFM Optical Particle Counter. Proceedings of the 20th DOE/NRC Nuclear Air Cleaning Conference, August 1988, Boston.Google Scholar
  14. Lieberman, A., & Stockham, J., 1961. Automatic Techniques of Airborne Particle Counting. Air Engineering 2(1):37–39.Google Scholar
  15. Niida, T., et al., 1988. Counting Efficiency of Condensation Nuclei Counters in N2, Ar, CO2 and He. Journal of Aerosol Science 19(7): 1417–1420.CrossRefGoogle Scholar
  16. Sinclair, D., 1982. Particle Size Sensitivity of Condensation Nucleus Counters. Atmospheric Environment 16(5):955–958.CrossRefGoogle Scholar
  17. Stolzenburg, M. R., & McMurry, P. H., 1984. A Theoretical Model for an Ultrafine Aerosol Condensation Nucleus Counter. In Aerosols, ed. B. Y. H. Liu, et al., pp. 59–62. New York: Elsevier.Google Scholar

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© Van Nostrand Reinhold 1992

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  • Alvin Lieberman

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