Continuous Flow Diffusion Chamber – Ice Activation Spectrometer (CFDC-IAS)

The CFDC-IAS measures ice nucleating particle (INP) concentrations in real- time. Based on Colorado State University’s design that has a long and successful track record of INP measurements, the CFDC-IAS adds a number of automation features to enable autonomous and reliable long-term operation in the laboratory or field. Product applications include Laboratory INP characterization, Field ambient INP measurement, Aerosol-cloud interactions, Climate research and Weather modification and cloud seeding.

The CFDC-IAS exposes sampled aerosol particles to controlled temperature and water saturation conditions found in mixed-phase clouds. It features two ice-coated cylindrical copper walls that are kept at different temperatures to drive temperature and water vapor pressure gradients between them. The different rates of diffusion for water vapor and heat lead to a region between the walls that is super-saturated with respect to ice, and depending on the magnitude of the gradient, water. Aerosol passing between the walls freeze either directly as ice crystals (deposition freezing) or first activate as a supercooled liquid droplet, which may then freeze (condensation/ immersion freezing). Ice crystals formed in the chamber are counted with an optical particle counter at the exit of the chamber.