基于位置灵敏碲锌镉康普顿相机的GEANT4模拟与图像重建OA

The Compton camera is a new type of γ-ray imaging device with potential for high detection efficiency and high resolution imaging in large and wide field of view application scenarios.This paper aims to construct a Compton camera model based on the three-dimensional position-sensitive CdZnTe(3D-CZT)detector,and to obtain the imaging detection efficiency of the Compton camera,the factors affecting the image quality,and the methods of imaging optimization.A Compton camera based on the 3D-CZT model is constructed using GEANT4.The simple back-projection algorithm is used to reconstruct the image of a far-field 137Cs point source.The factors affecting the angular resolution of imaging are analyzed.The imaging angular resolutions in the polar and azimuthal directions are 19.1° and 18.9°,respectively.The intrinsic imaging detection efficiency is 16.2％.The Compton scattering angle measurement deviations due to the Doppler effect,energy measurement deviation,position measurement deviation,and far-field approximation deviation are 2.2°,4.2°,17.5°,and 1.0°,respectively.Energy measurement deviations lead to little change in the reconstructed Compton scattering angle distribution,whereas position measurement deviations induce a shift from the large-angle end toward smaller angles in the distribution.The position-resolution capability of the detection system is the dominant factor affecting the imaging angular resolution.In order to enhance the imaging precision,it is necessary to improve the position-resolution capability of the Compton camera as much as possible.The simulation results provide a reference for the design of γ-ray imaging devices and the optimization of image reconstruction.