X射线傅里叶关联成像中的康普顿散射噪声研究(特邀)

Research on Compton scattering noise in the X-ray Fourier-transform ghost imaging(Invited)

傅里叶变换关联成像(FGI)是利用光场的高阶关联特性提取样品傅里叶信息的成像方法,对光源空间相干性要求较低,从而为小型化高分辨X射线显微提供了新的技术途径。然而在实际应用中往往要求有限光通量以减小样品辐射损伤,同时X射线与样品发生相互作用时康普顿散射的存在也会降低信噪比。针对以上问题,模拟研究了光通量有限条件下的X射线FGI,结果表明在探测面光通量0.1 phs/pixel条件下仍然能够获得样品的振幅和相位信息,并且利用Geant4蒙特卡洛程序模拟分析了金单质、硅单质和血红蛋白三种样品所产生的康普顿散射噪声对FGI成像结果的影响,结果显示相比于传统的X射线衍射成像,计入康普顿散射噪声后的FGI仍具有良好的抗噪性。

Fourier-transform ghost imaging(FGI) is an imaging method which exploits the high-order correlation characteristics of optical fields to extract the Fourier information of samples. Due to its low requirement for the coherence of the light source, it provides a new technical approach for miniaturizing and highresolution X-ray microscopy. However, in practice, limited X-ray flux is often required to reduce radiation damage to the sample, and the existence of Compton scattering will reduce the signal-to-noise ratio when X-ray photons interact with the sample. To solve these problems, X-ray FGI with limited flux was studied by simulation.The results showed that when the detection flux was 0.1 PHS/pixel, the amplitude and phase information of the sample could still be obtained. The Geant4 Monte Carlo simulation program was adopted to analyze the influence of Compton scattering noise generated by the gold, silicon and hemoglobin samples in X-ray FGI. The results indicated that FGI could achieve better Compton scattering noise resistance than traditional X-ray diffraction imaging.