Recently, it has been suggested that the First Sharp Diffraction Peak (FSDP) in glasses arises from a quasi-periodicity of void spaces in the structure, that plays the role of the lattice spacing of crystals, and that the Boson Peak (BP) in glasses could result from a piling up of the vibrational states near the boundary of the pseudo-Brillouin zone (PBZB).We propose to identify the contribution of collective excitations along the position of the PBZB in two borate glasses, characterized by different FSDP and BP positions, in order to verify if the FSDP acts as a sort of Brillouin zone center for glasses and if the observed BP arises from the piling up of the vibrational states near the related PBZB.Considering the kinematic range of interest, the MARI spectrometer is suited to enable a successful experiment.We request three different incident neutron energies and a beam time of 4 days.