Details
| Original language | English |
|---|---|
| Pages (from-to) | 223-229 |
| Number of pages | 7 |
| Journal | International Journal for Ion Mobility Spectrometry |
| Volume | 15 |
| Issue number | 4 |
| Publication status | Published - 5 Jul 2012 |
Abstract
Most state of the art gas sensor systems based on atmospheric pressure ionization, such ion mobility spectrometers use radioactive beta-sources (e. g. 3H or 63Ni) to provide free electrons with high kinetic energy to initiate a chemical gas phase ionization of the analytes to be detected. Here, we introduce a non-radioactive electron emitter which generates free electrons at atmospheric pressure. Therefore, electrons are generated in a vacuum by field emission and accelerated towards a 300 nm thin 1 mm 2 silicon nitride membrane separating the vacuum from atmospheric pressure. Electron currents of about a few hundred microamps can be reached. High energetic electrons of about 10 keV can easily penetrate the membrane without significant loss of kinetic energy. The concept of proximity focusing avoids complex electron lenses to focus the electron beam onto the membrane. The used field emitter tips are made of multi-walled carbon nanotubes. Another benefit of our system is that no insulated power supply operating at high voltage is needed, as necessary for thermo emitters. Here, we show a first prototype of a proximity focused electron gun with field emitting carbon nanotubes. The system is coupled to our drift tube ion mobility spectrometer for validation. Ion mobility spectra similar to those of a 3H ionization source were achieved.
Keywords
- Atmospheric pressure ionization source, Carbon nanotubes, Non-radioactive electron gun, Proximity focusing
ASJC Scopus subject areas
- Chemistry(all)
- Spectroscopy
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In: International Journal for Ion Mobility Spectrometry, Vol. 15, No. 4, 05.07.2012, p. 223-229.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Towards a miniaturized non-radioactive electron emitter with proximity focusing
AU - Cochems, Philipp
AU - Langejuergen, Jens
AU - Heptner, Andre
AU - Zimmermann, Stefan
PY - 2012/7/5
Y1 - 2012/7/5
N2 - Most state of the art gas sensor systems based on atmospheric pressure ionization, such ion mobility spectrometers use radioactive beta-sources (e. g. 3H or 63Ni) to provide free electrons with high kinetic energy to initiate a chemical gas phase ionization of the analytes to be detected. Here, we introduce a non-radioactive electron emitter which generates free electrons at atmospheric pressure. Therefore, electrons are generated in a vacuum by field emission and accelerated towards a 300 nm thin 1 mm 2 silicon nitride membrane separating the vacuum from atmospheric pressure. Electron currents of about a few hundred microamps can be reached. High energetic electrons of about 10 keV can easily penetrate the membrane without significant loss of kinetic energy. The concept of proximity focusing avoids complex electron lenses to focus the electron beam onto the membrane. The used field emitter tips are made of multi-walled carbon nanotubes. Another benefit of our system is that no insulated power supply operating at high voltage is needed, as necessary for thermo emitters. Here, we show a first prototype of a proximity focused electron gun with field emitting carbon nanotubes. The system is coupled to our drift tube ion mobility spectrometer for validation. Ion mobility spectra similar to those of a 3H ionization source were achieved.
AB - Most state of the art gas sensor systems based on atmospheric pressure ionization, such ion mobility spectrometers use radioactive beta-sources (e. g. 3H or 63Ni) to provide free electrons with high kinetic energy to initiate a chemical gas phase ionization of the analytes to be detected. Here, we introduce a non-radioactive electron emitter which generates free electrons at atmospheric pressure. Therefore, electrons are generated in a vacuum by field emission and accelerated towards a 300 nm thin 1 mm 2 silicon nitride membrane separating the vacuum from atmospheric pressure. Electron currents of about a few hundred microamps can be reached. High energetic electrons of about 10 keV can easily penetrate the membrane without significant loss of kinetic energy. The concept of proximity focusing avoids complex electron lenses to focus the electron beam onto the membrane. The used field emitter tips are made of multi-walled carbon nanotubes. Another benefit of our system is that no insulated power supply operating at high voltage is needed, as necessary for thermo emitters. Here, we show a first prototype of a proximity focused electron gun with field emitting carbon nanotubes. The system is coupled to our drift tube ion mobility spectrometer for validation. Ion mobility spectra similar to those of a 3H ionization source were achieved.
KW - Atmospheric pressure ionization source
KW - Carbon nanotubes
KW - Non-radioactive electron gun
KW - Proximity focusing
UR - http://www.scopus.com/inward/record.url?scp=84869202555&partnerID=8YFLogxK
U2 - 10.1007/s12127-012-0108-y
DO - 10.1007/s12127-012-0108-y
M3 - Article
AN - SCOPUS:84869202555
VL - 15
SP - 223
EP - 229
JO - International Journal for Ion Mobility Spectrometry
JF - International Journal for Ion Mobility Spectrometry
SN - 1435-6163
IS - 4
ER -