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| Titel |
Performance evaluation of a high-resolution parallel-plate differential mobility analyzer |
| VerfasserIn |
J. P. Santos, E. Hontañón, E. Ramiro, M. Alonso |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 9, no. 7 ; Nr. 9, no. 7 (2009-04-03), S.2419-2429 |
| Datensatznummer |
250007159
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| Publikation (Nr.) |
 copernicus.org/acp-9-2419-2009.pdf |
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| Zusammenfassung |
A high-resolution differential mobility analyzer (DMA), specially designed
for (i) the measurement of ion mobility spectra, and (ii) the generation of
a continuous stream of monomobile ions, has been developed and tested. The
apparatus consists of two parallel-plate electrodes between which an
electric field is applied. The test ion stream flows into the instrument
through a narrow rectangular slit made in one of the electrodes, and
migrates toward the other electrode driven by the applied field, while being
transported by a stream of clean air which flows parallel to the plates at
Reynolds number between 2×104 and 9×104 in laminar flow
conditions. The collector electrode contains also a narrow slit through
which ions of the desired mobility are withdrawn out of DMA. The classified
ion current is measured with a high-sensitivity electrometer having a noise
level around 0.1 fA.
The theory behind the DMA operation is first discussed, focusing on the
special case of parallel-plate geometry. Some generic results showing the
stability and repeatability of the measurements and the resolving power of
the instrument are presented next. The last part of the paper deals with the
application of the apparatus to the study of the effect of humidity and
aging time on the mobility spectra of air ions generated by a low-activity
241Am source. |
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