We have developed a compact sample transfer vessel. It consists of coaxial type linear motion feedthrough, vacuum vessel and sample catcher. The sample can be analyzed by using this system without exposing to atmosphere. The vessel pressure reached ∼ 4.6 × 10^-4 Pa and kept 1 × 10^-3 Pa for 20 days. The aluminum on which an argon sputtering was carried out was kept in this equipment for 41 hours. Then, ∼ 1.0 nm thick oxide film was formed on the surfaces. The oxide film thickness was about 1 ⁄ 4 of the natural oxide layer thickness.

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Atomic structural analysis methods for crystal surfaces by reflection high-energy positron diffraction are described with a dynamical diffraction theory for positron beams. Using the one-beam approximation method, surface normal components of atomic positions are determined easily. Subsequently surface lateral components are determined by a dynamical analysis of rocking curves at symmetrical incidence for a certain crystal axis and/or the analysis of intensity distribution of spots in diffraction patterns using the result of the one-beam analysis. For adsorbed surfaces, it is noted that it is easy to determine adsorption heights of adsorbates by a one-beam rocking curve at the total reflection region. As examples of surface structural analyses, methods of atomic structure determinations for the Si(111)√21×;√21-Ag and the Si(111)7×7 surface are described.

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