Multiport particle chamber validation for particle number concentration using condensation particle counters

A Multiport Particle Chamber (MPC) has been developed to enable up to 24 particle sensors to be assessed simultaneously. The MPC was characterised using Condensation Particle Counters (CPC). Testing of the MPC demonstrated a 1% variation in particle concentration for both port-to-port variability and sampling depth dependence around the central ring of the MPC. The MPC was compared to a 4-way flow splitter using various CPCs (from TSI Incorporated) and the results were found to agree to within the variability of the measurements. Dilution and dampening within the MPC was also assessed indicating a 92.5% dilution of the generated particle source. Two instrument comparisons were conducted: the first between CPC and Droplet Measurements Technologies (DMT, Boulder, Co.) Cloud Condensation Nuclei counter (CCN) and the second between the water-based TSI 3786-LP CPC and the butanol-based TSI 3775 CPC challenged with a hydrophilic aerosol. The results of this investigation show that the MPC is suitable for multi low flow rate instrument (0.3 lpm) particle number concentration intercomparisons, using the central ring of the MPC and up to 100 nm nominal particle diameter.