Details
| Original language | English |
|---|---|
| Pages (from-to) | 247-255 |
| Number of pages | 9 |
| Journal | International Journal for Ion Mobility Spectrometry |
| Volume | 15 |
| Issue number | 4 |
| Publication status | Published - 9 May 2012 |
Abstract
With optimized geometry and operating parameters both IMS selectivity and sensitivity can be significantly increased. However, finding these parameters and geometry requires an accurate knowledge of the electrical field and the ion concentration within the IMS at any time of operation. Furthermore, the ion loss at metallic surfaces and space charge effects caused by the moving ion cloud must be considered. This is particularly true when using non-radioactive electron emitters which generate a comparably high space charge density at electron currents similar to radioactive beta-sources due to their smaller ionization volume. This can lead to a reduced IMS resolution mainly caused by coulomb repulsion. In this work a transient model which enables a detailed view on the electric field within the IMS considering ion diffusion and migration as well as ion loss and coulomb repulsion is presented. This finite element model provides excellent agreement between simulated IMS spectra and experimental data especially when considering space charge effects and coulomb repulsion respectively. The model is used to design a short drift tube IMS with significantly improved resolution. Furthermore, this model allows considering ion-ion and ion-neutral reactions, such as ion generation, charge transfer reactions and ion-ion recombination. Moreover, fluid dynamics can be considered as required for modeling aspiration type IMS.
Keywords
- Coulomb repulsion, FEM, Finite element model, IMS, Ion mobility spectrometry, Transient simulation
ASJC Scopus subject areas
- Chemistry(all)
- Spectroscopy
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In: International Journal for Ion Mobility Spectrometry, Vol. 15, No. 4, 09.05.2012, p. 247-255.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Results of a transient simulation of a drift tube ion mobility spectrometer considering charge repulsion, ion loss at metallic surfaces and ion generation
AU - Langejuergen, Jens
AU - Cochems, Philipp
AU - Zimmermann, Stefan
PY - 2012/5/9
Y1 - 2012/5/9
N2 - With optimized geometry and operating parameters both IMS selectivity and sensitivity can be significantly increased. However, finding these parameters and geometry requires an accurate knowledge of the electrical field and the ion concentration within the IMS at any time of operation. Furthermore, the ion loss at metallic surfaces and space charge effects caused by the moving ion cloud must be considered. This is particularly true when using non-radioactive electron emitters which generate a comparably high space charge density at electron currents similar to radioactive beta-sources due to their smaller ionization volume. This can lead to a reduced IMS resolution mainly caused by coulomb repulsion. In this work a transient model which enables a detailed view on the electric field within the IMS considering ion diffusion and migration as well as ion loss and coulomb repulsion is presented. This finite element model provides excellent agreement between simulated IMS spectra and experimental data especially when considering space charge effects and coulomb repulsion respectively. The model is used to design a short drift tube IMS with significantly improved resolution. Furthermore, this model allows considering ion-ion and ion-neutral reactions, such as ion generation, charge transfer reactions and ion-ion recombination. Moreover, fluid dynamics can be considered as required for modeling aspiration type IMS.
AB - With optimized geometry and operating parameters both IMS selectivity and sensitivity can be significantly increased. However, finding these parameters and geometry requires an accurate knowledge of the electrical field and the ion concentration within the IMS at any time of operation. Furthermore, the ion loss at metallic surfaces and space charge effects caused by the moving ion cloud must be considered. This is particularly true when using non-radioactive electron emitters which generate a comparably high space charge density at electron currents similar to radioactive beta-sources due to their smaller ionization volume. This can lead to a reduced IMS resolution mainly caused by coulomb repulsion. In this work a transient model which enables a detailed view on the electric field within the IMS considering ion diffusion and migration as well as ion loss and coulomb repulsion is presented. This finite element model provides excellent agreement between simulated IMS spectra and experimental data especially when considering space charge effects and coulomb repulsion respectively. The model is used to design a short drift tube IMS with significantly improved resolution. Furthermore, this model allows considering ion-ion and ion-neutral reactions, such as ion generation, charge transfer reactions and ion-ion recombination. Moreover, fluid dynamics can be considered as required for modeling aspiration type IMS.
KW - Coulomb repulsion
KW - FEM
KW - Finite element model
KW - IMS
KW - Ion mobility spectrometry
KW - Transient simulation
UR - http://www.scopus.com/inward/record.url?scp=84869213954&partnerID=8YFLogxK
U2 - 10.1007/s12127-012-0095-z
DO - 10.1007/s12127-012-0095-z
M3 - Article
AN - SCOPUS:84869213954
VL - 15
SP - 247
EP - 255
JO - International Journal for Ion Mobility Spectrometry
JF - International Journal for Ion Mobility Spectrometry
SN - 1435-6163
IS - 4
ER -