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| Titel |
Modeling the UV Signal Scattered into the Lunar Dust Experiment (LDEX) from the Lunar Surface |
| VerfasserIn |
Zoltan Sternovsky, Sam Gagnard, David Gathright, Eberhard Gruen, David James, Sascha Kempf, Mark Lankton, Mihaly Horanyi, Ralf Srama, Jamey Szalay |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250090441
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| Publikation (Nr.) |
 EGU/EGU2014-4679.pdf |
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| Zusammenfassung |
| The Lunar Dust EXperiment (LDEX) instrument onboard the Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft is currently characterizing the distribution of dust around the Moon and its temporal variability. LDEX is an impact ioni-zation dust detector with a sensor area of ~ 0.01 m2. The impact target is of a hemispherical shape and a radial electric field is used to focus the generated ions onto a microchannel plate (MCP) detector. LDEX has two modes of detecting dust: Particles larger than about r > 0.3 micron produce sufficiently large charges and can be detected as individual impact events. A potentially large population of smaller grains, r < 0.3 micron, can be identified by measuring their collective signal by integrating the MCP signal for ~100 ms periods. This integrated signal then enables the identification of regions with a high-density of particles that are too small to be detected individually. The LDEX instrument is also sensitive to the UV light that enters the instrument and may scatter into the MCP detector. LADEE is on a low-inclination orbit and the LDEX instrument it turned off while the Sun is in its field-of-view (FOV). Shortly after passing the subsolar point the LDEX instrument is turned on and flies over the sunlit lunar surface until it crosses the terminator. The preliminary data show that on some orbits the background signal is quiet, while on other obits there are contributions from additional sources, possibly ions beams. The motivation for the present work is to remove the contribution from UV backscat-tered from the lunar surface in order to identify and characterize the signal sources of interest. The prelimi-nary calculation of the UV background signal is based on the photometric properties of the lunar surface de-rived by Hapke [Theory of reflectance and emittance spectroscopy (Cambridge University Press, 2nd ed., 2005)] and Lucke et al. [Far-ultraviolet albedo of the Moon, Astron. J. 81, 1162 (1976)], using parameters measured by previous space missions, and the cali-brated sensitivity of the LDEX instrument. The pre-liminary model reproduces the general shape of the data, however, the model needs to be updated to obtain better agreement. |
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