An ultrahigh vacuum apparatus for H atom scattering from surfaces.

We present an apparatus to study inelastic H or D atom scattering from surfaces under ultra-high vacuum conditions. The apparatus provides high resolution information on scattering energy and angular distributions by combining a photolysis-based atom source with Rydberg atom tagging time-of-flight. Using hydrogen halides as precursors, H and D atom beams can be formed with energies from 500 meV up to 7 eV, with an energy spread of down to 2 meV and an intensity of up to 108 atoms per pulse. A six-axis manipulator holds the sample and allows variation of both polar and azimuthal incidence angles. Surface temperature can be varied from 45 K up to 1500 K. The apparatus' energy resolution ( E / Δ E ) can be as high as 1000 and its angular resolution can be adjusted between 0.3° and 3°.