Surface effects on the angular distributions of samarium vapor effusing from cylindrical orifices

A mass-spectrometric investigation has been made of the angular distributions of atomic samarium vapor effusing from cylindrical orifices of varying geometries and materials. Neither the theoretical angular distribution curves obtained from the Clausing theory nor any of the existing modifications of this theory coincided with the experimental distributions. The substantial effect of orifice material on the angular distribution curves suggests the possibility of bulk diffusion in the orifice walls as a contributory factor.