This paper describes the design, construction, and test of a setup able to make thermal neutron irradiation at grazing angles of incidence on a sample lying inside an isotropic high neutron flux. Such characteristics are deemed to be very interesting for the future research facilities that will provide intense neutron beams. Indeed, collimated beams can be found easily in neutron sources around the globe, but the new equipment enables use of a relatively intense flux that will allow fast testing of materials. The aim of this study is the understanding of the mechanical stability of structural materials used for the manufacturing of neutron guides such as borosilicate glasses. This new equipment proved the unstability of some of these glasses to thermal neutron irradiation when exposed above a given fluence.