ETD

• Energetic Neutral Atoms (ENA)
• gas detector
• graphene
• MICROMEGAS

The observation of Energetic Neutral Atoms (ENA) is important in space physics because ENAs trace solar wind–planet interactions without being affected by electromagnetic fields. The SWEATERS project aims to develop a compact detector able to measure the energy, direction, and species of ENAs in the 1–100 keV range. Its core is a low-pressure MICROMEGAS gas detector that enables ultra-thin entrance windows, essential to preserve ENA properties. This thesis contributes to the development and characterization of a first prototype in a CubeSat-compatible configuration, combining experimental tests and simulations. Experimentally, the main task was selecting an entrance window material with high ion transparency, strength up to 100 mbar, and low gas permeability. Bi-layer graphene on support grids was chosen for its minimal thickness, robustness, and UHV compatibility. I performed leak-tightness tests using an RGA, evaluated different adhesives, and studied graphene transparency to 1–5 keV H₂⁺ and He⁺ ions at a dedicated beamline, taking part in alignment, commissioning, and measurements of transmission, scattering, and energy straggling. In parallel, I developed Geant4 simulations to optimize geometric acceptance and model charge transport in an Ar:CO₂ mixture, estimating the effective active region and the trade-off between spatial resolution, sensitivity, and compactness. Overall, the work provides a solid basis for the next steps of the SWEATERS project.