EFFECT OF MECHANICAL POLISHING ON THE SURFACE-STRUCTURE OF GLASSES STUDIED BY GRAZING ANGLE NEUTRON REFLECTOMETRY

Grazing angle neutron reflectometry, optical and mechanical roughness profilometry techniques have been used to study the effects of the pol ishing operations on the surface of Borkron Schott glass (special boro silicate glass for neutron optics applications) as the polishing tool pressure P and the mean grain size of the polishing powder PHI. The ne utron reflectivity investigations have shown that there is formation o f a layer at the surface glass substrate. This layer is less dense tha n the bulk substrate and its thickness is around 60 angstrom. The opti cal and mechanical profilometry measurements have shown that both roug hness and waviness decrease with P and PHI. All the experimental resul ts show a good correlation between the neutron refractive index, the t hickness and the roughness of the surface layer and the waviness of th e glass surface with the two mechanical polishing parameters. The prev ious techniques have been completed by secondary ion mass spectroscopy and atomic force microscopy measurements.