Development of an improved field ionization detector incorporating a secondary electron stage
Field ionization from sharp tips is attracting increased attention for use in detectors for neutral atomic/molecular species. However, the direct detection of the ionized species typically results in low sensitivities due to the small acceptance angle of the receiving ion-sensitive measurement devic...
| Main Authors: | , , , , , |
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| Format: | Journal Article |
| Published: |
IOP Publishing Ltd
2011
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| Subjects: | |
| Online Access: | http://hdl.handle.net/20.500.11937/10372 |
| Summary: | Field ionization from sharp tips is attracting increased attention for use in detectors for neutral atomic/molecular species. However, the direct detection of the ionized species typically results in low sensitivities due to the small acceptance angle of the receiving ion-sensitive measurement device (usually a channel electron multiplier) and can result in sputtering damage due to the relatively high mass and energy of the incident ion species. Here we present a design for a field-ionization-based neutral atom detector incorporating a simple secondary electron generating stage. The use of such a stage decouples the field-ionized species from the detected electron signal, thus eliminating any sputtering damage to the channel electron multiplier. The detector armature discussed is shown to exhibit a linear response to neutral gas pressure and a sensitivity that is improved by more than two orders of magnitude over a previous field ionization detector design. |
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