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Airborne particles are separated according to their electrical mobilities using a microfabricated corona ionizer and separator electrodes. Oleic acid particles with sizes ranging from 30 to 300 nm are used to characterize the device. They are generated using a TSI 3075 constant output atomizer. These particles are electrically charged by a microfabricated corona ionizer, and the resultant particle electrical mobility is a function of the size of the particle. A varying dc potential difference of 0-2 kV across the separator electrodes selects charged particles of various electrical mobilities. These separated particles are subsequently counted using a TSI 3025A Condensation Particle Counter. The device demonstrated its ability to separate particles between 50 and 130 nm into five distinct size bins. The operational flow rate is 0.5 L/min, and the micropin-between-planes corona ionizer operates at 1.3 kV with 7 [mu]A. The theoretical and experimental electrical mobilities of the particles are compared. [2008-0091] Index Terms--Aerosol instrumentation, corona ionizer, particle electrical mobility, particle separation.

A microfabricated corona ionizer is developed for miniaturized air particle monitoring instruments. Peek's breakdown criterion and Warburg's Law are used to calculate the required electrode geometries. Single mask electroplating is employed as the microfabrication technique. Devices with discharge pin radius of 20 [micro]m and interelectrode spacing of 1.4, 1.8, 2.0, and 2.2 mm are fabricated and tested. The inception voltages in the range from 1.4 to 2 kV are achieved without substrate breakdown. It consumes relatively low power at 150 mW or less. Corona charging currents of more than 50 [micro]A were achieved before streamers break down. The experimental results also demonstrated the nondependency of the inception voltage on the pin's radius of curvature so long as it is significantly smaller than the interelectrode spacing. There is only one value of inception voltage for each given interelectrode spacing ( 1.4 to 2.2 ram) with the pin's radius of curvature ranging from 10 to 200 [micro]m. This implies that strict dimensional control is not required in the microfabrication process in order to ensure the same inception voltage for each device. [2007-0152] Index Terms--Avalanche, corona, discharge, electroplating, inception, ionizer, microfabricated, plasma, streamer.