Monte Carlo Simulation Of The Angle And Energy Straggling Of Proton In Thin Target

Rutherford backscattering analysis(RBS) refers to that when heavy charged particle beam bombards the target material, small part of the heavy charged particles scatters in large angle. Backscattering analysis technique in the development of RBS, has become a very sophisticated analytical tool, widely used in solid surface element analysis, impurity content and so on.A certain energy beam of charged particles through the target, the energy will no longer be the certain value.Statistical fluctuation of the collision process, produces the angle straggling and energy straggling of charged particles .The angle and energy straggling in the back scattering analysis is an important parameter, which seriously affects the size of the resolution of the backscattering analysis. In addition, in the Ion implantation, High-energy proton radiography and Heavy-ion cancer treatment, etc., the angle and energy straggling can not be ignored too. In general application, there are early Bohr theory and the Highland theory describing angle straggling and energy straggling. Qualitative analysis is possible, but quantitative analysis sometimes has large deviations. Although some of the later theories have development, but there is no significant improvement in the degree of compliance with the experiment.Monte Carlo method can vividly describe random events and simulation experiment process. This method has been widely applied to include all kinds of nuclear test and been used to simulate nuclear experiments widely. It can simulate various micro-physical processes by using the known reaction cross section data. GEANT4 is a large object-oriented Monte Carlo package developed by the European organization for nuclear research (CERN) and Japanese High Energy Physics (KEK) and other more than twenty units. Since the launch, due to the superiority of its object-oriented, GEANT4 has been applied in a large range.This paper mainly uses Monte Carlo method to conduct the following two simulation work: simulate the angle straggling and the energy straggling of the incident proton energy of 1 ~ 10MeV, into beryllium, aluminum, copper, tantalum and lead in different thickness and make clear the relationship between the angle and energy straggling with the incident proton energy, target atomic number and thickness. Through simulation, it can be drawn the following conclusions:â‘ the angle straggling mainly has connection with the incident proton energy, the target materials and thickness of the target. In the same target material circumstance, the higher the incident proton energy is, the smaller the angle straggling is. And when the incident proton energy is the same, the larger the target material atomic number or thickness is, the larger the angle straggling is.â‘¡energy straggling is also associated with the target material, mainly the surface electron density. The greater the electron density is, the greater the transmission proton energy straggling is. Energy straggling is also associated with the incident proton energy. The general trend is the greater incident proton energy, the smaller the energy straggling.