  The Gas Electron Multiplier (GEM) detector is one of the advanced members of
the Micro Pattern Gas Detector (MPGD) family, used in High Energy Physics (HEP)
experiments as a tracking device due to its high rate handling capability and
good spatial resolution. The uniformity in the performance of the detector is
an essential criterion for any tracking device.
  The presence of the dielectric medium (Kapton) inside the active volume of
the GEM chamber changes its behaviour when exposed to external irradiation.
This phenomenon is known as the charging-up effect. In this article, the
uniformity in terms of gain, energy resolution and count rate of a Single Mask
(SM) triple GEM chamber of dimension 10 cm $\times$ 10 cm are reported for both
the charged-up and uncharged GEM foils.
