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Titel |
Characterisation of a new Fast CPC and its application for atmospheric particle measurements |
VerfasserIn |
B. Wehner, H. Siebert, M. Hermann, F. Ditas, A. Wiedensohler |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1867-1381
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Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Measurement Techniques ; 4, no. 5 ; Nr. 4, no. 5 (2011-05-06), S.823-833 |
Datensatznummer |
250001976
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Publikation (Nr.) |
copernicus.org/amt-4-823-2011.pdf |
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Zusammenfassung |
A new Fast CPC (FCPC) using butanol as working fluid has been built based on
the setup described by Wang et al. (2002). In this study, we describe the new
instrument. The functionality and stable operation of the FCPC in the
laboratory, as well as under atmospheric conditions, is demonstrated. The
counting efficiency was measured for three temperature differences between
FCPC saturator and condenser, 25, 27, and 29 K, subsequently resulting in a
lower detection limit between 6.1 and 8.5 nm. Above 25 nm the FCPC reached
98–100% counting efficiency compared to an electrometer used as the reference
instrument. The FCPC demonstrated its ability to perform continuous
measurements over a few hours in the laboratory with respect to the total
particle counting. The instrument has been implemented into the airborne
measurement platform ACTOS to perform measurements in the atmospheric
boundary layer. Therefore, a stable operation over two hours is required. The
mixing time of the new FCPC was estimated in two ways using a time series
with highly fluctuating particle number concentrations. The analysis of a
sharp ramp due to a concentration change results in a mixing time of 5 ms
while a spectral analysis of atmospheric data demonstrates that for
frequencies up to 10 Hz coherent structures can be resolved before sampling
noise dominates. |
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