Use of an Alternating Gradient Cloud Chamber to Measure the Performance of a Condensation Nucleus Counter
An aerosol sampling project for the Air Force (Whitefield et al 1993), generated the need to make particle concentration measurements in the size range ≤10 nm, and a Met One CNC (Model 1100-5) was used for these measurements. The Met One small size performance and efficiency vs. particle concentration were calibrated against an ALGR/OPC facility (ALternating GRadient continuous flow thermal diffusion cloud chamber (CFD) and Optical Particle Counter), using a laboratory generated NaCl aerosol for which the critical supersaturation spectrum is both well known and low. The advantage of the ALGR is that it and the Model 1100-5 can operate under similar aerosol concentration conditions. These studies show that the Met One CNC begins to drop below 100% counting efficiency at aerosol diameters ≤10 nm, and reaches 75% efficiency at 7 nm. Complementary electrometer measurements were made for comparison.
D. E. Hagen et al., "Use of an Alternating Gradient Cloud Chamber to Measure the Performance of a Condensation Nucleus Counter," Proceedings - Annual Technical Meeting - Institute of Environmental Sciences, vol. 1, pp. 319-335, Institute of Environmental Sciences, Jan 1993.
39th Annual Technical Meeting of Institute of Environmental Sciences (1993: May 2-7, Las Vegas, NV)
Mechanical and Aerospace Engineering
Keywords and Phrases
Aerosols; Calibration; Cloud chambers; Condensation; Detectors; Particle size analysis; Particles (particulate matter); Performance; Sampling; Thermal diffusion; Alternating gradient continuous flow thermal diffusion cloud chamber; Condensation nuclei counter; Optical particle counters; Optical instruments
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International Standard Serial Number (ISSN)
Article - Conference proceedings
© 1993 Institute of Environmental Sciences, All rights reserved.