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| Titel |
Characterisation of corona-generated ions used in a Neutral cluster and Air Ion Spectrometer (NAIS) |
| VerfasserIn |
H. E. Manninen, A. Franchin, S. Schobesberger, A. Hirsikko, J. Hakala, A. Skromulis, J. Kangasluoma, M. Ehn, H. Junninen, A. Mirme, S. Mirme, M. Sipilä, T. Petäjä, D. R. Worsnop, M. Kulmala  |
| 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. 12 ; Nr. 4, no. 12 (2011-12-16), S.2767-2776 |
| Datensatznummer |
250002152
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| Publikation (Nr.) |
 copernicus.org/amt-4-2767-2011.pdf |
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| Zusammenfassung |
| We characterized size and chemical composition of ions generated by a
corona-needle charger of a Neutral cluster and Air Ion Spectrometer (NAIS)
by using a high resolution differential mobility analyzer and a
time-of-flight mass spectrometer. Our study is crucial to verify the role of
corona-generated ions in the particle size spectra measured with the NAIS,
in which a corona charger is used to charge aerosol particles down to the
size range overlapping with the size of generated ions. The size and
concentration of ions produced by the corona discharging process depend both
on corona voltage and on properties and composition of carrier gas. Negative
ions were <1.6 nm (0.8 cm2 V−1 s−1 in mobility) in all
tested gas mixtures (nitrogen, air with variable mixing ratios of water
vapour), whereas positive ions were <1.7 nm (0.7 cm2 V−1 s−1). Electrical filtering of the corona generated ions and not
removing all charged particles plays an important role in determining the
lowest detection limit. Based on our experiments, the lowest detection limit
for the NAIS in the particle mode is between 2 and 3 nm. |
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