N. L. Popov

X-Ray reduction imaging of inclined reflective masks at critical angles

We have proposed and simulated optical schemes for producing reduced images by X-ray lasers or harmonic generators at a wavelength of . The mask in this case is placed at a small angle to the optical axis, corresponding to the angle of total external reflection of the material. We have determined the optimal position of the detector (resist) and the corresponding spatial resolution. The results can be used to solve problems in nanotechnology and nanostructuring of surfaces.

Laser-Electron X-Ray Generator

The possibility of developing a laser-electron x-ray generator based on the Thomson scattering of laser radiation by relativistic electrons and prospects for its application are considered. In its specifications (brightness, average intensity, and dimensions), as well as its construction and operation cost, such a generator is intermediate between x-ray tubes and synchrotron sources. The configuration of channels and experimental stations intended for applications of an x-ray laser-electron generator in studies of the elemental composition and structure of materials is discussed.

On contrast of biological X-ray nanomicroscopy

We analyse the absorption contrast of histological and cytological preparations, which can be achieved in nanomicroscopic studies using monochromatic radiation in the spectral range of 90 – 600 eV (14 – 2 nm). Two types of unstained biological objects are considered: untreated and fixed in paraffin, and optimum wavelengths are determined for the study of samples with a thickness of 0.5 – 10 μm with a spatial resolution of 100 – 20 nm. Taking into account the efficiency of X-ray optics, the number of source photons required to produce a single image is estimated. It is shown that the greatest interest for the study of fixed objects represents the spectral region of 7 – 14 nm, for which, on the basis of rapidly developing compact sources of incoherent and coherent radiation and effective optics, microscopes for scientific and clinical research can be designed.

2D simulation of coherent images of tilted objects

A simple derivation of the field transformation in the optical system for direct and tilted objects is proposed. It is used for developing an algorithm and programs of numerical determination of the spatial resolution of optical systems. It is planned to apply the developed methods to reflection X-ray microscopy.

Determination of the parameters of multilayer nanostructures using two-wave X-ray reflectometry

A method for determining the parameters of multilayer nanostructures by measuring the angular dependence of the X-ray reflectance at two wavelengths has been considered. A calculation scheme taking into account the specificity of the method was suggested, which allows operation with samples of any size and shape. The scheme was applied to C/Ni/C, Si1−xGex, and AlxGa1−xAs multilayer structures. It was shown that two-wave reflectometry allows elimination of the influence of instrumental errors; hence, the thickness, density, and composition of both polycrystalline and monocrystalline nanostructure layers reliably determined.