Experimental characterization of a low-pressure MICROMEGAS detector for low energy ion measurements

A compact low-pressure MICROMEGAS detector was developed to study low-energy ion-gas interactions, relevant for space plasma diagnostics, fusion edge studies, direct dark matter searches and microdosimetry. Using a dedicated ion beam facility, we measured the ionization quenching factor for low energy light ions in Ar/CO2mixtures at pressures below 150 mbar, demonstrating its independence from pressure and detector gain. These results made it possible to establish an absolute energy calibration scale that can be used with any detector filled with the same gas mixture. A custom discrete-component readout chain, combined with a new reconstruction method, enabled accurate reconstruction of ion impact points.