FAAM NON-CORE ultrafine condensation particle counter (CPC)


The TSI 3025a ultrafine condensation particle counter (CPC) measures total aerosol concentration from a nominal 3 nm to maximum of 3 µm. This instrument uses Butan-1-ol as the condensing agent. The instrument was installed on the old CCN rack prior to May 2008 and on the new CCN rack after. In both fits it has sampled via the second rosemount pair on the port side of the aircraft. The instrument was discontinued as part of the instrument fit on the BAe-146 from June 2008. It was replaced with the TSI modified water filled 3786 model.


 Below are the product overview and full manual for the TSI 3025a butanol filled CPC:


The instrument's particle concentration ranges from 0 to 9.99*104 with an accuracy of ±10 % up to 105 particles cm-3. This is output at 1Hz with other parameters in the FAAM core data product. The concentration measurement is reported at ambient pressure and a temperature of 39oC. The last flight with any data from this instrument in B380 on May 21st 2008. Prior to May 2008 the diffusional loss on the smallest particles was unknown post this period they can be estimates at... 
There are limitations to this measurement, the Johnson Williams liquid water content should be used as flag to exclude data as water drops shatter on the inlet and enhance the concentrations. There is also some issue with water mixing with the butanol and contaminating the condensing vapour.
The inlet flow of the instrument can be set at 1.5 liters per minuet or 0.3 liters per minuet. To ensure as high a spatial resolution as possible the instrument has been operated at the higher flow.
 Below is part of the data set that encouraged the replacement of the TSI 3025a CPC with the TSI modified 3786 CPC.