A computer program which simulates Rutherford backscattering spectra is currently in use at Cornell University and other institutions. Straggling and detector resolution are among the effects included. Samples are considered to be made up of a finite number of layers, each with uniform composition. The emphasis in the mathematics is on accuracy beyond that of iterated surface approximation methods. Thicker layers can thus be analyzed without a net loss in accuracy. The mathematical description of the sample can then have fewer layers and fewer calculations are required. This paper provides estimates of the number of arithmetic operations used by the program for any simulation to demonstrate the tradeoffs between accuracy, computation time, and algorithm sophistication.

Algorithms for the rapid simulation of Rutherford backscattering spectra

This document describes the use of the program SIMNRA and the physical concepts implemented therein. SIMNRA is a MicrosoftWindows program for the simulation of backor forward scattering spectra for ion beam analysis with MeV ions. SIMNRA is intended for the simulation of spectra with Rutherford scattering cross-sections (RBS), non-Rutherford cross-sections (EBS), nuclear reactions (NRA), elastic recoil detection analysis (ERDA) with light and heavy incident ions, and medium energy ion scattering (MEIS). SIMNRA can calculate spectra for any ion-target combination including incident heavy ions and any geometry including backscattering, forward scattering, and transmission geometries. Arbitrary multi-layered foils in front of the detector and arbitrary multi-layered windows (such as exit windows for an external beam) in front of the sample can be used. Several different stopping power data sets are available. Energy loss straggling is calculated including the corrections by Chu and Yang to Bohr’s theory, energy loss straggling propagation in thick layers is taken into account. Additionally the effects of multiple small-angle and plural large angle scattering can be calculated approximately as well as surface and substrate roughness. Many non-Rutherford and nuclear reaction cross-sections for incident protons, deuterons, 3He-, 4He-, 6Liand 7Li-ions are included. Data fitting (layer thicknesses, compositions etc.) is possible by means of the Simplex algorithm. OLE automation allows automated analysis of large numbers of spectra and the development of new applications. SIMNRA supports the IBA data format (IDF) for data storage and exchange of data between different simulation programs. SIMNRA is easy to use due to the graphical Microsoft Windows user interface: SIMNRA makes full use of the graphics capacities of Windows. SIMNRA shell extensions extend the abilities of Windows Explorer and Windows Search, thus allowing a seamless integration of SIMNRA into the Windows system.

http://www2.if.usp.br/~lamfi/guia-simnra.pdf

SIMNRA user's guide

Ion beam crystallography of surfaces and interfaces

Energy loss, range, path length, time-of-flight, straggling, multiple scattering, and nuclear interaction probability: In two parts. Part 1. For 63 compounds Part 2. For elements 1 ⩽ Z ⩽ 92

Since the seventies a large number of computer methods have been developed for data analysis in Rutherford backscattering spectrometry (RBS). A short review of published computer methods for ion scattering is presented. The majority of programs can be divided into two categories: the interactive spectrum synthesis and the spectrum analysis codes. In this paper recent trends and problems in the area of spectrum simulation are presented. I demonstrate the main methods and approaches on our RBX computer program. The program can use any particle-target combination and beam energy between 100 keV and 10 MeV. The calculations and fitting methods of non-Rutherford scattering cross section are included. The contributions from electronic screening, the corrected Bohr straggling and the geometrical straggling are discussed. The useful techniques for extracting an accurate depth-concentration profile directly from RBS or ERDA spectrum are discussed. Some examples of the discussed methods are also given.

N. Matsunami

Papers

How accurate are absolute rutherford backscattering yields

Energy loss of He ions in solidified gases