  The purpose of this work is to study the change in the structure of the Ge-Se
network upon doping with Ag. The total structure factor S(Q) for two samples
has been measured by neutron diffraction using the two-axis diffractometer
dedicated to structural studies of amorphous materials, D4, at the Institut
Laue Langevin. We have derived the corresponding radial distribution functions
for each sample and each temperature, which gives us an insight about the
composition and temperature dependence of the correlation distances and
coordination numbers in the short-range. Our results are compatible with the
presence of both GeSe4/2 tetrahedra and Se-Se bonds. The Ag atoms are linked to
Se in a triangular environment. Numerical simulations allowing the
identification of the main peaks in the total pair correlation functions have
complemented the neutron diffraction measurements.
