Beryllium and tungsten are seen at present as the most suitable wall materials for the future international tokamak ITER and they are presently tested at JET. The formation of binary Be¿W alloys under plasma action is one of the most important issues in plasma¿wall interaction processes at the tokamak wall. In this contest, we propose the study of mixed materials through neutron scattering, in particular we will focus on two different samples and namely 1) a sample of dust collected on the JET divertor during the 2012 intervention by vacuum cleaning and 2) a section of a JET tile from the so-called ITER-like wall. If the composition and/or relative quantities of the different Be-W compounds on the tile are significantly different from that in the dust, it would be a most interesting information about the nature of the possibly competing interactions encountered by the beryllium.