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The Advanced Small Analyzer for Neutrals (ASAN) on the Chang'E-4 Rover Yutu-2

Abstract : The Advanced Small Analyzer for Neutrals (ASAN) is a compact mass resolving energetic neutral atom analyzer flown on the Yutu-2 rover of the Chinese Chang'E-4 mission to the Moon. ASAN measures energetic neutral atoms in the energy range from 10 eV to 10 keV with typically 30% energy resolution. The field-of-view is a single angular pixel of 37° × 30° pointing at lunar surface. Energetic neutral atoms enter the instrument through a charge particle deflection system and are then ionized on a diamond-like carbon conversion surface. Positive ions from the conversion surface are energy analyzed using an electrostatic analyzer and their velocity is subsequently determined in a time-of-flight section using ceramic channel electron multipliers as detectors. The obtained mass resolution m/Δ m is about 2, comfortably separating neutral hydrogen, helium, and the oxygen-group (≥16 amu). A full energy spectrum for energetic neutral atoms is obtained in 3 seconds. Switching the charged particle deflection system off, ASAN also directly measures positive ions with similar performance as for energetic neutral atoms. Including electronics the instrument weighs 970 g and consumes 3.4 W.
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Contributor : Nathalie POTHIER Connect in order to contact the contributor
Submitted on : Thursday, May 19, 2022 - 8:00:35 PM
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M. Wieser, S. Barabash, X. -D. Wang, A. Grigoriev, A. Zhang, et al.. The Advanced Small Analyzer for Neutrals (ASAN) on the Chang'E-4 Rover Yutu-2. Space Science Reviews, 2020, 216, ⟨10.1007/s11214-020-00691-w⟩. ⟨insu-03673142⟩



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