4He atomic beam scattering from clean surfaces of silicon and germanium

Abstract

A modulated, nozzle type 4He atomic beam has been used to investigate scattering from clean, room temperature surfaces of silicon and germanium. The surfaces are prepared by cleaving in situ under ultrahigh vacuum, the pressure being in the low 10−9 Torr range. The beam can be operated with the source gas at room temperature or cooled with liquid nitrogen, resulting in a wavelength of ∼0.57 and ∼1.07 Å, respectively. The scattered beam is subspecularly directed with a maximum intensity less than 1% of the incident beam intensity.