CFDC (Continuous flow diffusion chamber)
The Continuous Flow Diffusion Chamber (CFDC) measures ice nucleating particles (INP) by exposing sampled air to controlled temperature and relative humidity conditions and optically detecting any ice crystals formed. It features a concentric cylindrical nucleation and growth chamber with inner and outer walls coated by a thin layer of ice. By controlling the wall temperatures to generate a specified temperature gradient the CFDC can produce a region within the growth chamber of known temperature and relative humidity, including super-saturated conditions. The instrument is capable of measuring INP over a wide range of conditions relavant to mixed phase cloud conditions.
Rogers, D. C., P. J. DeMott, S. M. Kreidenweis, and Y. Chen, A Continuous-Flow Diffusion Chamber for Airborne Measurements of Ice Nuclei, Journal of Atmospheric and Oceanic Technology, 18, 725-741, 2001.
DeMott, P. J., et al., Sea spray aerosol as a unique source of ice nucleating particles, Proceedings of the National Academy of Sciences, 113, 5797-5803, 2016.
Bi, K., et al., Continuous measurements of ice nucleating particles in Beijing, China, submitted to Journal of Geophysical Research, 2019.
Technical Specifications (brochure)
Size: 26" x 50" x 60" (D x H x W)
Weight: ~225 kg
Power: 100-230 VAC, 50/60 Hz, 6000 W
Size range: D < 2.5 um
Sample flow rate: 1.5 LPM
Sensitivity: ~1/L depending on operating conditions
Response time: 3-5 minutes depending on INP concentrations
Required consumables: Nitrogen @ 15 PSI for purge air, DI water for wall icing, ethanol or other refrigeration fluid for cooling systems, silica gel and molecular sieve for diffusion dryers (included)
Data system: Included data acquisition hardware and PC, pull out keyboard/monitor tray