A UHV-compatible ΔE− E gas telescope for depth profiling and surface analysis of light elements

Abstract

We have developed a compact ΔE− E gas telescope that can easily be incorporated into a standard ultrahigh vacuum ion scattering chamber. If energetic, heavy ions are available as a primary beam, the gas telescope can be used to detect light elastic recoils scattered from the surface region of a sample. The detector consists of a gas ionization chamber in front of a surface-barrier detector. The energy loss signal in the gas ( ΔE) is taken in coincidence with the energy signal in the surface-barrier detector ( E) to identify both the atomic number and the total energy of the elastic recoil. The design parameters of the detector have been chosen to allow detection of elements from H to O with good depth resolution ( < 100 Å) and submonolayer sensitivity. The mass resolution is adequate to easily separate all elements from H to O.