A MAGIC concept for self-sustained, water-based, ultrafine particle counting

Abstract

A self-sustaining, motion-tolerant, water-based condensation particle counter (CPC) has been designed, fabricated, and tested. Referred to as “MAGIC” for moderated aerosol growth with internal water cycling, the particle size response is similar to the 5-nm cut-point commercial CPCs. MAGIC is a laminar-flow instrument with three temperature stages: cool, warm, and cool. The middle warm-walled stage initiates the condensational growth and the final cool-walled stage maintains supersaturated conditions while recovering water vapor. By using a continuous wick throughout all three stages, the system recharges itself through a combination of water condensate from the sampled airstream and recovery of water vapor from the peak supersaturation region. A reservoir-less prototype system based on this concept was built and tested. Experiments show equal performance in any orientation, upright or inverted, and tolerance to tipping, shaking and vibrational shocks up to 5 g. Under mild ambient conditions, it provided multi-week operation without replenishing the wick.Copyright © 2018 American Association for Aerosol Research