Geant4-based Simulation Of⁴He And¹²C Ions Rutherford Backscattering

As an important technique of the ion beam analysis, Rutherford BackscatteringSpectrometry （RBS） is a non-destructive, rapid and direct analysis technique ofdetecting impurity concentration and depth on surface of material. The techniqueshows distinct advantages in the field of research&production of ion implantation,thin film, semiconductor and other new materials. RBS has a high practical value anda wide range of applications.In recent years, many scholars simulated RBS-related problems by means ofMonte Carlo programs. Monte Carlo method, based on the theory of probability andstatistics, is known as random or statistical skills experimental method. The methodcould realistically describe the characteristics and procedure of particle transportproblems. Geant4is a toolkit for the simulation of particles passing through andinteracting with matter. Its areas of application include high energy, nuclear andaccelerator physics, as well as studies in medical and space science. Geant4isdeveloped and maintained by the international Geant4Collaboration.The RBS of⁴He and¹²C ions respectively were simulated in the energy of270KeV and500KeV in different material in this thesis. The results were as follows:（1） When⁴He ions vertically incident on the films occur scattering, ion angulardistribution performs symmetrical characteristics. From theoretical formula,kinematic factor changes slowly with angle larger than160°. In addition, the RBS wassimulated at different angles by Geant4. According to the result of theory andsimulation, a ring detector was placed at160°-170°to collect the information ofbackscattered ions which can improve efficiency of the simulation.（2） When the species and energy of particle are constant, the elements of thesample material were determined according to the energy of the back scatteringspectroscopy. The half-width of the backscattering spectra changing with the film thickness linearly, the film thickness could be calculated by analyzing the half-widthof backscattering spectra.（3） The Rutherford Backscattering spectra （RBS） for270keV,500keV⁴He and¹²C normally incident on Au, Ag, Cu thin films were simulated using Geant4. TheRBS characters of⁴He,¹²C are analyzed, it is found that the mass resolution of¹²CRBS is much better than that of⁴He RBS.