报告题目：Ptychographic X-Ray Computed Tomography with Synchrotron Radiation Facilities
报 告 人：陈波 研究员（同济大学）
Ptychographic X-ray computed tomography (PXCT) [1, 2] is a newly developed three-dimensional (3D) phase-sensitive imaging method which currently offers a spatial resolution less than 15nm in three dimensions . It combines X-ray ptychography , a scanning coherent X-ray diffractive imaging method, with conventional computed tomography. This technique provides quantitative high-contrast non-noise 3D maps with absolute electron density values from phase contrast information because X-ray ptychography is an approach to solve the X-ray refractive index, n=1-δ+iβ, of the target objects. In which the real part δ has a relation with the electron density of the materials. As with the conventional X-ray tomography, PXCT collects many 2D projections of the samples from different directions, and then reconstruct these 2D projections into 3D images, which makes it gain the capabilities to do 3D imaging as well.
With the development of the dedicated instrumentation for the X-ray ptychographic tomography and the algorithms for the phase tomography reconstruction in the last a few years, the technique becomes extremely powerful in resolving 3D fine structure of a large range of samples starting from bones, biological tissues, silk fibers to coatings, devices, integrated circuits/CPUs and various nano- and micro-particles etc. The technique could be further developed and applied to obtain invaluable information for materials science and to offer helps to the industrial developments.
 Dierolf, M. et al. Ptychographic X-ray computed tomography at the nanoscale. Nature. 467, 436-439 (2010).
 Guizar-Sicairos, M. et al. Phase tomography from x-ray coherent diffractive imaging projections. Opt. Express 19, 21345-21357 (2011).
 Holler, M. et al. High-resolution non-destructive three-dimensional imaging of integrated circuits. Nature. 543, 402-406 (2017).
 Rodenburg, J. M. et al. Hard-X-Ray lensless imaging of extended objects. Phys. Rev. Lett. 98, 034801 (2007).