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| Titel |
Photoemission from glass dust grains: First results |
| VerfasserIn |
Libor Nouzak, Radim Pechal, Jiri Pavlu, Jana Safrankova, Zdenek Nemecek |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250074196
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| Zusammenfassung |
| Dust grains are widely present in both interstellar space as well as on numerous space
objects like the Moon or asteroids. Quite often, the dust consists of large amount of
SiO2. While every object in the space is exposed to impacting particles from the
Sun (photons, electrons, and ions), the dust grains become charged. Interesting
phenomena (e.g., Lunar horizon glow, dust fountains, and levitation) may appear as a
consequence of different conditions at the light and dark lunar sides. Although they where
observed already during Apollo and Surveyor missions, these effects are still not fully
understood.
We present laboratory measurements carried on the single SiO2 grain of micron size
caught in the electrodynamic trap and exposed to UV and electron irradiations. Analyzing the
dust motion (oscilation frequency and position), we can evaluate its specific charge. In this
paper, we are comparing equilibrium charge-to-mass ratios given by a secondary
electron emission induced by 400Â eV electrons (about a maximum of the secondary
emission) and by the UV-induced photoemission from the He I lamp (-Â 21Â eV). Initial
results indicate that the resulting charge is about twice larger for photoemission. |
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