Gaseous Electron Multiplier (GEM), foil holes deformation studies

GEM detectors play an important role in the upcoming high-luminosity LHC upgrade in 2018 where they will be exposed to high doses of radiation in the muon endcap region. A series of tensile tests were performed on neutron irradiated and non-irradiated GEM foils where the shape of the holes was thoroughly examined. It was found that the GEM foil does not deform much at lower loads but the deformation gets exponentially bigger after applying more than a 60 N force. Both sets of samples behaved similarly at lower loads up to 40 N after which the holes of the irradiated samples started to deform more rapidly than the non-irradiated ones. The failure point of the non-irradiated samples occurred consistently at around 135 N while the irradiated samples experienced failure at around 85 N with two outliers failing at 120 and 135 N.