  Gas Electron Multiplier (GEM) is one of the mostly used gaseous detectors in
the High Energy Physics (HEP) experiments. GEMs are widely used as tracking
devices due to their high-rate handling capability and good position
resolution. An initiative is taken to study the stability in performance of the
GEM chamber prototypes in the laboratory using external radiation for different
Argon based gas mixtures. The effect of ambient parameters on the gain and
energy resolution are studied. Very recently some behavioural changes in the
performance of a SM GEM chamber is observed. The details of the experimental
setup, methodology and results are reported here.
