@article {Kuang:2012:0278-6826:309,
title = "Modification of Laminar Flow Ultrafine Condensation Particle Counters for the Enhanced Detection of 1 nm Condensation Nuclei",
journal = "Aerosol Science and Technology",
parent_itemid = "infobike://tandf/uast",
publishercode ="tandf",
year = "2012",
volume = "46",
number = "3",
publication date ="2012-03-01T00:00:00",
pages = "309-315",
itemtype = "ARTICLE",
issn = "0278-6826",
eissn = "1521-7388",
url = "https://www.ingentaconnect.com/content/tandf/uast/2012/00000046/00000003/art00006",
doi = "doi:10.1080/02786826.2011.626815",
author = "Kuang, Chongai and Chen, Modi and McMurry, Peter H. and Wang, Jian",
abstract = "This paper describes simple modifications to thermally diffusive laminar flow ultrafine condensation particle counters (UCPCs) that allow detection of 1 nm condensation nuclei with much higher efficiencies than have been previously reported. These non-destructive modifications
were applied to a commercial butanol-based UCPC (TSI 3025A) and to a diethylene glycol-based UCPC (UMN DEG-UCPC). Size and charge dependent detection efficiencies using the modified UCPCs (BNL 3025A and BNL DEG-UCPC) were measured with high resolution mobility classified aerosols composed
of NaCl, W, molecular ion standards of tetra-alkyl ammonium bromide, and neutralizer-generated ions. With negatively charged NaCl aerosol, the BNL 3025A and BNL DEG-UCPC achieved detection efficiencies of 37% (90\texttimes increase over TSI 3025A) at 1.68 nm mobility diameter (1.39 nm geometric
diameter) and 23% (8\texttimes increase over UMN DEG-UCPC) at 1.19 nm mobility diameter (0.89 nm geometric diameter), respectively. Operating conditions for both UCPCs were identified that allowed negatively charged NaCl and W particles, but not negative ions of exactly the same mobility size,
to be efficiently detected. This serendipitous material dependence, which is not fundamentally understood, suggests that vapor condensation might sometimes allow for the discrimination between air ions and charged particles. As a detector in a scanning mobility
particle spectrometer (SMPS), a UCPC with this strong material dependence would allow for more accurate measurements of sub-2 nm aerosol size distributions due to the reduced interference from neutralizer-generated ions and atmospheric ions, and provide increased sensitivity for the determination
of nucleation rates and initial particle growth rates.",
}