Numerical Simulation Of Non-coherent X-ray Grating Interference Phase Contrast Imaging Technology

X-ray has been used extensively as a detective tool in non-destructively determining the inner structure of objects since 1895. However, the traditional absorption-contrast imaging has a defect in samples which are called weak-absorption material, due to its low sensitivity. X-ray phase-contrast imaging has become a hot spot because of the advantage of extremely high sensitivity for weak-absorption material, which was developed since 1990s. For now, grating-based technology is the only way that can be competent under x-tube sources in all phase-contrast imaging tehnologys. The core procedure of grating-based phase-contrast imaging is the Talbot effect of phase-grating. And the visibility of Talbot fringes is one of the most important factors which influences the quality of phase-contrast image.In order to further investigate X-ray grating-based phase contrast imaging. We are going to make a numerical program, and mainly complete the following steps:Firstly, we derive the equations of grating-based phase-contrast imaging. And use python language to make a program (GT-LLX).Secondly, we use the program to simulate Talbot effect of phase-grating(Si) under coherent wave, and compare the fringes visibility of ideal phase grating and real phase grating.Thirdly, we simulate Talbot effect under non-coherent x-ray beam (Au source-grating is used). Simulation results show that fringes visibility is mainly determined by the imaging distance, duty circle of source grating, but less effected by the source size and amplitude distribution.Fourthly, we simulate the Talbot effect under Gaussian and X-ray tube spectrums. Simulation results show the when spectrum width(E/?E) larger than 2, the fringes visibility is more than 0.6. Especially, the fringes visibility is maximum on the mean energy of source.Finally, we simulate the phase-contrast imaging of Si,Au,Ni,Air sphere samples(and compound sample), also give two cases of X-ray grating-based phase-contrast imaging system under x-tube sources, one is designed for single energy17.5keV (mean energy) with? phase-grating, the other is designed for double energy17.5keV?35keV (mean energy) with ?/2 phase-grating...