High Energy Electrophotographic Simulation Based On Geant4

In recent years, Charged particle radiography has a greatly development as a new radiography technique. Compared with traditional radiography, it improves the diagnostic capability of fluid dynamic experiment at density resolution, material resolution, multi-angle dynamic radiography and so on. Nowadays, proton radiography (pRad) can achieve millimeter magnitude spatial resolution, so it applies the diagnostic of macro-scale. Compared with pRad, electron radiography (eRad) can achieve micrometer magnitude spatial resolution in theory, so eRad can distinguish more subtle construction. Besides, it is easier to achieve high-energy electron. This article will study the imaging ability of electron to high-density and thick target by using Geant4 and building the model of GeV electron radiography.The model of electron radiography includes two parts:the interaction of electron with target and magnifying magnetic lens.It is the fundamentals of eRad that the interaction of electron with target will change particle’s energy and angle. Geant4 as an open toolkit, can achieve the interaction of electron with target in selecting physical process by itself. The result shows that the simulation results from Geant4 is the same as theory, so it can study the influence of interaction on radiography.Imaging system is needed to achieve high spatial resolution for eRad. It includes matching section and imaging section. Matching section can modify the electron’s state to meet eRad’s requirements. Imaging section is composed of two pairs of quadrupole magnets, can achieve point to point image by focusing and defocusing. In order to finish imaging system, we need to get the parameters of quadrupole magnets by Transport procedure to set these parameters in Geant4.Based on the previous theory, we can finish the model of GeV electron radiography. Later we just set the primary electronic parameters to achieve the results we want.In this paper, we analyze the ability of spatial resolution and the influence of secondary particles on image quality through different material and thick target. The result shows that 12GeV high energy electron can achieve micrometer magnitude spatial resolution; its image blur only submicron scale and chromatic aberrations caused by image beamline is mainly contribution, and the influence of secondly particle can be neglected.Besides, we design image beamline is used to 2.5GeV eRad verification experiment and build the model of 2.5GeV eRad to evaluate 2.5GeV electron’s image ability from spatial resolution, density resolution and marginal image blur. At the same time, the simulation research offers powerful data support to 2.5GeV eRad verification experiment. The result shows that 2.5GeV eRad can achieve the spatial resolution of submicron scale and five percent density resolution; it can keep pace with central image blur and marginal image blur by electron modulation.