In the case of AsSe:Sn and Ge27Sb13Se60 amorphous thin films deposited on Si(100) wafer, it was observed that the diffraction pattern is distorted by the escape-peak, which is very sensitive in intensity to the wafer's position in its own plane, This peak was found to be superimposed on the first sharp diffraction peak, which characterises the medium range order in the amorphous materials. A method for the minimisation of the escape-peak effect is presented. A different method is suggested to avoid this peak.