Physical conditions of computer analysis of ion backscattering

Abstract

The physical effects on computer data analysis of 4He and 1H ion backscattering have been investigated. The consequences of the low-energy tail effect, undetected elements, the nonunique correspondence between the sample and the spectrum, screening and nuclear effects on the scattering cross sections, and the energy response of the silicon surface barrier detector have been studied from the point of view of spectrum synthesis. Cases are pointed where these physical effects should be taken into account. Usually their consequences are neglected in ‘‘standard’’ computer programs since they are considered to have secondary importance. It is shown that ‘‘standard’’ procedures are well justified only in treating those parts of 4He backscattering spectra which arise near the surface region of the sample at about 2-MeV ion energy.