We wish to measure the partial dynamical structure factors and the partial vibrational density of states (VDOS) for the archetypal network forming glass GeSe2 by using the method of isotope substitution in neutron scattering and the MERLIN spectrometer. Essentially, by averaging the separated Ge-Ge and Se-Se partial dynamical structure factors over Q, it is possible to obtain the exact VDOS for Ge and Se, respectively. The work builds on an initial test experiment using MERLIN (RB920266) where there was a substantial background scattering problem associated with use of an Al cryostat tail. Instead, in the new experiment, a ¿cold finger¿ will be used to remove this background scattering problem while still giving access to low temperatures. This is important to ensure that the harmonic approximation is valid and to minimise the multi-phonon contribution to the sample scattering.