AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
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Transfer Function of a New DMA and Its Use with a DEG-CPC for SMPS Measurements Starting at 1nm
JACOB SCHECKMAN, Mark R. Stolzenburg, Michel Attoui, Hee-Siew Han, Juergen Spielvogel, TSI Incorporated
Abstract Number: 532 Working Group: Instrumentation and Methods
Abstract SMPS systems employing a DMA for sizing and a CPC for counting are widely used for measurement of aerosol particle size distributions. Measurements of particles as small as 1nm in diameter are needed in many applications. Diethylene glycol (DEG) has been used as a working fluid to grow sub-2.5nm particles to a size detectable with a butanol-based CPC (Iida et al, 2009), enabling SMPS size distributions in this size range (Jiang et al, 2011). Recently, TSI introduced the Model 3086 1nm-DMA and the Model 3777 Nano Enhancer which, when combined with a CPC (Model 3772), and suitable neutralizer, form a 1nm-SMPS system capable of size distribution measurements from 1-50nm. Here we characterized the components of this system and combined them for SMPS measurements down to 1nm.
The transfer function and penetration of the TSI Model 3086 1nm-DMA was characterized using monomobile molecular ion standards. Particles were generated by electrospray, and classified with a high-resolution DMA before being introduced into the Model 3086 DMA under test. The concentration upstream and downstream of the test DMA was measured in order to report the DMA penetration efficiencies. The data were inverted using a routine employing the diffusive transfer function introduced by Stolzenburg in order to obtain the true transfer function for the DMA under test.
The response of the TSI 3777 Nano Enhancer+3772 CPC-combination to mobility-classified NaCl was compared to a TSI Model 3068B Aerosol Electrometer and gave a CPC lower detection limit (d50) of 1.4nm, consistent with data from the literature for similar designs. The concentration linearity, response time and CPC false count rate of the combination were also characterized.
Iida, K., Stolzenburg, M. R., and McMurry, P. H. (2009). AS&T, 43(1), 81–96.
Jiang, J., Chen, M., Kuang, C., Attoui, M., and McMurry, P. H. (2011). AS&T, 45(4), 510–521.