New computer iterative fitting program DVBS for backscattering analysis

Abstract

A new computer program DVBS for the backscattering (BS) analysis and simulation of the backscattered ions energy spectra was developed. The stimulus was the possibility to calculate the depth concentration profiles from the BS spectra at the specimen interfaces and surfaces to obtain the diffusion coefficients. The program was being developed and improved since December 1989 till 1992, when the last version was finished, and is currently used at IP SAS and LNP JINR. The effects of detector resolution, straggling and non-Rutherford or resonant scattering cross section are included in the program analysis. Using graphics possibilities of a PC computer the program offers a very easy way to handle the data which allows to treat complicated multielement BS spectra and reduce the treatment error down to the theoretical accuracy limit of the method. The great advantage of this program is the possibility to display directly on the screen which part of the spectra corresponds to a given layer of the concentration profile. The interfaces between the layers for a given element in displayed concentration model (or concentration histogram) are linked directly to the corresponding channels in the simultaneously overlapped plots of the theoretically generated and experimentally measured spectra. Thus it is possible to adjust the concentration model on the base of the spectra comparison in a channel region which corresponds to a given layer. With new improved BS techniques, the heavy ions become frequently used. The DVBS can use any type of projectiles from proton to uranium and accepts user's scattering cross section, and stopping powers tabulated in a very simple way. This paper offers the short overview and new aspects and methods of the spectra treatment.