Sultan B. Dabagov

Single-reflection regime of x rays that travel into a monocapillary

We present an analysis of the transmission of x rays through a single monocapillary under the single-reflection regime. Because ray tracing does not provide an explanation for experimental data, we give a qualitative interpretation of the observed behavior within the framework of wave theory.

Focusing of X-rays by capillary systems

Abstract The structure and form of the focal spot when focusing X-rays in the energy range from 7 keV to 10 keV by Kumakhov lenses were investigated. It is shown that owing to focusing the radiation concentration abruptly increased. For the first time the interference structure of a focal spot came to light. Possibilities of using a Kumakhov lens as an analyzer with high spectral resolution and as a point source of X-ray radiation are discussed.

Coherent and incoherent components of a synchrotron radiation spot produced by separate capillaries

We discuss soft-x-ray focusing properties of separate capillaries. It is shown that a nonnegligible fraction of the synchrotron radiation beam transmitted by the capillary is modal. Experimental and theoretical data are discussed to explain the superposition pattern of x rays in the focal plane due to the interference phenomena of electromagnetic radiation propagating through separate capillaries.

X-ray propagation through hollow channel: PolyCAD – a ray tracing code

Abstract “PolyCAD”, a CAD program designed for X-ray photon tracing in polycapillary optics, is described. To understand the PolyCAD code and its results, the theoretical bases of X-ray transmission by a single cylindrical channel (monocapillary) are discussed first. Then cases of cylindrical, lens and semi-lens shaped polycapillary optics are examined. PolyCAD allows any type of X-ray source to be used: an X-ray tube of finite beam dimensions or an astrophysical object can be simulated in combination with the polycapillary optics. The radiation density distribution images formed on a screen located at various focal distances are discussed. The good agreement of the PolyCAD results with experimental and previous theoretical calculations validate the code.

X-ray channeling in capillary systems

In the paper a theoretical model for calculation of x-ray photon characteristics under passage through capillary systems is described. The model is based on a numerical solution of a wave equation. It is shown that recently discovered interference effect under multiple reflection of x rays is an evidence of wave properties of x rays. In this report an explanation of the observed phenomenon is given.

The DAΦNE‐Light Facility

The new Synchrotron Radiation facility at Frascati exploits the intense photon emission from DAΦNE, the 0,51 GeV storage ring circulating over 1 A of electrons. Among the three beamlines commissioned, the Synchrotron INfrared Beamline At Daφne (SINBAD) is fully operational by a brilliant SR beam spanning the entire IR. Recently, the soft X‐ray beamline has been characterized and, once implemented the double‐crystal monocromator, X‐ray Absorption Spectroscopy is applied on material standards in the distinguishing energy region below 4 keV. An UltraViolet line, presently dedicated to photobiology dosimetry, has also given first results on cell irradiation in the UVB band.

Divergence of x-ray beams transmitted by capillary structures

The study of transmitting and focusing properties of capillary optical systems shows that a number of unexpected effects takes place during the experiments. One of those effects is a decrease of the beam divergence behind capillary structures. In this report we have considered an alignment procedure for capillary optics samples and presented the result on scattering of x rays at grazing angles. Decrease in beam divergence behind capillary systems is explained by use of the wave scattering theory for description of x-ray propagation.

Influence of the internal structure of a capillary channel on the propagation of soft x radiation

In the last years several coherent phenomena associated with the propagation of soft x-ray synchrotron radiation through capillary optical elements (polycapillary lenses and systems of capillaries) have been observed and investigated. Interference effects produced by soft x radiation travelling inside assembled capillary systems may be explained in the framework of the wave propagation theory. In this report a theoretical analysis of the dependence of the transmission characteristics by the internal structure of the capillary channel is presented and discussed.

Scattered radiation suppression by means of x-ray capillary systems

Possibility of using the capillary reflecting structures (cones, lenses, pillars) for creating a new type of antiscatter grid was investigated. The use of capillary structures allows us to suppress a scattered radiation and improve the contrast during an image transfer.

Synchrotron radiation focusing by means of Kumakhov lenses

Results of experiments on focusing of synchrotron radiation by means of Kumakhov lens are presented. For explanation of observed interference structure the wave theory describing channeling radiation is applied.