中能重离子照相成像模糊研究

Proton radiography has provided a potential development direction for advanced hydrotesting, however, the image blurring of which is a key problem that needs to be heavily studied. In this project, numerical simulation and partially experiment as an assistant method are used to investigate the entire physics mechanism of medium energy heavy ion beam travelling through the beamline and imaging at the image plane. The main points of this project that we concern about the image blurring are those various factors which causing the image blurring, including the chromatic aberration of imaging beamline, the insufficient modulation of incident particle's transverse displacement and angel deviation, the longitudinal length of object, background scattering, nuclear elastic scattering, quasi-elastic scattering and otherwise. Firstly, the numerical simulation by using the Monte Carlo code Geant4 will be implemented to reveal several physical problems in medium energy heavy ion radiography. Then some experiments will be performed at LanZhou HIRFL-CSR synchrotron to verify the theoretic analysis. And finally the conclusion drew from the heavy ion radiography will be extended to proton radiography. The study of this project is important and propectively will be a guidance to the optimization design of imaging beamline and the constructions of proton radiography equipments.

质子照相是辐射成像技术的发展方向，而成像模糊研究是其中的关键技术。本课题将以数值模拟为主、实验为辅的研究方式，深入研究中能重离子通过成像光路进行透射成像的全过程的物理机制，重点考察造成成像模糊的各种因素，包括磁透镜系统的色差效应、入射离子横向位移和倾角非完全调制、客体的纵向尺寸、背景辐射、核弹性散射以及准弹性散射等。本课题拟采用Monte Carlo模拟来揭示中能重离子照相中的物理问题，然后通过在兰州重离子加速器上进行照相实验对计算结果的准确性进行验证，并将结论推广至质子照相。本课题研究对成像光路的优化以及质子照相装置的设计具有重要指导意义。

质子照相技术是辐射成像技术的发展方向，而成像模糊是其中的关键。本课题以理论分析为主、实验为辅的研究方式，深入研究了质子束通过成像束线进行透射成像的全过程的物理机制，重点考察了造成成像模糊的各种因素，包括磁透镜系统的色差效应、入射粒子横向位移和倾角非完全调制、客体的纵向尺寸、爆炸容器的影响、背景辐射等。本课题开展的蒙特卡洛数值模拟结果很好的验证了成像模糊的解析解，同时对实验系统的布局有了更深入的理解。本课题在国内进行了首次质子照相原理性验证实验，证明了这种基于磁透镜强聚焦原理的质子透镜成像技术的优越性。最后，通过本课题的研究，寻找到了一些新的研究方向，包括点扩散函数研究、放大型成像技术、能损透射型成像技术，它们有望从原理上提升质子照相的分辨能力，是对质子照相前言技术的一种探索，目的是寻求原理上的突破，将质子照相技术的成像品质推向新的高度。