Characterisation of N2-GEM: a beam monitor based on Ar-N2 gas mixture

The gas recycle is nowadays an important issue for gaseous detectors operation under study and for this reason, scientists are testing new gas systems for GEM detectors. Since some gas purifier does not allow to use oxygen, the standard Ar-CO2 (70%-30%) cannot be used; thus, new gas mixtures are under investigation. This paper presents the study of a triple GEM detector filled with new gas mixture based on Argon and Nitrogen (Ar-N2) at different concentrations: 90%-10%, 80%-20% and 70%-30%. The GEM detector characterisation has provided the High Voltage working point for the gas mixtures and a comparison between the Ar-CO2 and the Ar-N2.