We are glad to invite you to the lecture by Prof. Dr. Victor Kohn (National Research Centre “Kurchatov Institute”) on November, 2.
The lecture “Theory of X-Ray Compound Refractive Lenses” will be delivered in room 227 (Building of the Institute for Physical and Mathematical Sciences and Information Technologies, 14 A. Nevskogo Str.) at 12:00 on November, 2.
Prof. Dr. Victor Kohn:
«Hundred years after a discovery of x rays by W. C. Roentgen the new very powerful source of x-ray radiation was created, namely, a synchrotron radiation source of third generation. First one was build in Grenoble (France) and was called ESRF. The source creates laser-like beams of x rays with a high degree of spatial coherence. This property allows users to develop a new method of investigating the inner structure of micro objects on the base of inhomogeneous phase shift profile created by objects. The new method is hundred times or more sensitive as compared to the absorption contrast. I was a coauthor of the pioner paper which demonstated possibilities of new technique. This paper is cited today more than thousand times and number of citations increases each day. I am going to make an introduction to the main principles of the x-ray phase contrast imaging, to discuss what is spatial coherence and how it may be created, to explain the methods of computer simulations of phase contrast images and the methods of solving the inverse problem of calculation the phase shift profile from the intensity profile registered by detector. The picture at the left demonstrates images of voids inside the silicon carbid single crystal of thickness 490 microns. The voids are the dislocation micropipes with the diameters from fractions of microns to several microns. Today the method of x-ray phase contrast is widely used in material science, biology, medicine, technologies and so on for a nondestructive study of inner structure of object»