  With the advancement of the accelerator systems and the requirements of high
luminosity particle beams to reach different physics goals, detectors with good
position resolution and high rate handling capability have become essential for
designing any High Energy Physics (HEP) experiments. The Gas Electron
Multiplier (GEM) detectors are widely used in many HEP experiments as a
tracking device because of their good spatial resolution and rate handling
capability. The presence of the dielectric medium inside the active volume of
the GEM detector changes its behaviour when exposed to external radiation. This
mechanism is commonly referred as the charging-up effect. In this article, the
effect of the charging-up phenomenon and the initial polarisation effect of the
dielectric on the gain of the chamber are reported for a single mask triple GEM
chamber with Ar/CO2 gas mixture.
