SEPARATION OF SCATTERED IONS AND NEUTRALS IN CAICISS WITH AN ACCELERATION TUBE

A coaxial impact-collision ion scattering spectroscopy (CAICISS) apparatus equipped with an acceleration tube in the flight path of its time-of-flight analyzer has been developed. This apparatus has been operated successfully to separate charged and neutral particles being backscattered at 180-degrees during ion scattering experiments. By the use of this technique, the neutralization probability of incident ions can be investigated in an atom-by-atom scheme, and subsequently the structural and electronic information of a given surface can be obtained simultaneously. In the present work, the apparatus has been employed to study the charge exchange of 2 keV He+ with Ag atoms at the Si(111) square-root 3 x square-root 3 R30-degrees -Ag surface and in Ag crystallites epitaxially grown on a Si(111) substrate.