Partner: FORTH
Operator: Christos Mitsios /Carolina Molina (LAPI/FORTH)
Link: https://www.cambustion.com/products/particle-classifiers/aac-aerodynamic-aerosol-classifier
Description: The Aerodynamic Aerosol Classifier (AAC) is a novel instrument that selects aerosol particles based on their relaxation time or aerodynamic diameter. The AAC employs two rotating concentric cylinders to create a well-defined flow field, allowing only particles with a specific relaxation time to pass through. This enables high-resolution measurements of particle size distributions from approximately 25 nm up to over 5 µm avoiding the multiple-charging artifacts that are present in electrostatic classifiers such as the Differential Mobility Analyzer (DMA).
When coupled with a Condensation Particle Counter (CPC), the AAC can operate in step-scan or continuous-scan modes to measure the full aerodynamic size spectrum. The continuous-scan mode (SASS) delivers higher spectral resolution and much faster scan times compared to step scanning. In monodisperse or set-point mode, the AAC isolates particles at a specific aerodynamic diameter: particles larger than the set-point are removed by impacting the classifier wall, while smaller particles follow the sheath flow and exit separately. This capability can be reversed in a low-pass separator configuration by modifying the outflow plumbing, the recorder can capture the smaller than set-point particles from the sheath flow for combination with other online instruments or analysis.