We propose to build a Transition Radiation Detector (TRD)
with Gaseous Electron Multiplier (GEM) amplification, referred as GEM-TRD,
to improve the electron-pion separation in the GlueX experiment.
It will allow to study precisely reactions with
electron-positron pairs in the final states; such reactions like
$J/\psi $ photoproduction near threshold have significant impact
in many fields of the particle physics.
The motivation for such an upgrade is followed by a
technical description the detector and the electronics.
Preliminary requirements for the GEM-TRD gas system are specified.
