Molecular Beam Study of Gas-Surface Interaction.(1st Report, In-plane and Out-of-plane Scattering of Gas Molecule).

Abstract

The experiment of a gas molecule scattering from a clean graphite surface is performed using the molecular beam technique. The molecular beam experiment is performed in the ultra high vacuum molecular beam scattering system. The supersonic molecular beam is produced in a three stage differentially pumped vacuum system by expansion of gas through a nozzle. In the second stage of the beam line, a rotating disc chopper is mounted to do time of-flight measurements. The base pressure in the main chamber where the graphite is placed is 3.7×10-7Pa (2.8×10-9 Torr). The graphite sample is mounted on a six-axis manipulator. The scattered molecule is detected by a rotatable quadrupole mass filter detector. By using the manipulator and the detector, the in-plane and out-of-plane scattering of a gas molecule can be measured.