arXiv subjects

R. A. Shaposhnikov

Publications and source records attributed to R. A. Shaposhnikov.

4 recordsLinked to original sources

arXiv2025

Structural and Thermal Stability of B4C/Ru Multilayers with Carbon Barrier Layers

The chemical interaction between Mo and Ru layers in multilayer structures depending on the thickness ratio ($Γ$) was carried out using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and X-ray reflectometry (XRR). The results showed significant interaction of materials inside multilayer structures with the formation of ruthenium borides, with an increase in the B4C layer thickness (a decrease in the $Γ$ parameter) leading to the formation of ruthenium borides of different stoichiometry. The introduction of a carbon barrier layer at the Ru-on-B4C interface resulted in significant suppression of ruthenium boride formation. The thermal stability of the B4C/Ru system was also studied upon annealing at 400$^{\circ}$C for 1 hour before and after the introduction of the carbon barrier layer. It was shown that the introduction of a carbon barrier layer at the Ru-on-B4C interface increases the thermal stability of the system, which makes this system more suitable for use in optical systems exposed to long-term radiation. The obtained results are important for the development of highly efficient multilayer mirrors used in EUV lithography and X-ray optics.

cond-mat.mtrl-sci↗

arXiv2021

Experiments on intense ion beam formation with inhomogeneous electric field

We report on a successful test of a new method for intense ion beam formation using an extraction with inhomogeneous electric field. Its key feature is a special shape of the extraction electrodes providing a higher rate of ion acceleration. It is applicable to any ion source type and could be used to improve performance of a wide range of plasma devices. The proof of concept was carried out using a high-current electron-cyclotron resonance ion source SMIS 37. High efficiency of the new extraction and proton beam formation with a record current density of up to 1.1 A cm-2 was demonstrated.

physics.plasm-ph↗

arXiv2020

Status of a point-like neutron generator development

In this paper we report on a high current density ion beam profile diagnostics with a slit-based system as a reliable method, capable of high thermal load applications. The task arose in frames of a point-like neutron source development for neutron radiography. In previous research, it was suggested to construct such a system as a D-D neutron generator based on the high current gasdynamic ion source, which utilises the plasma of electron cyclotron resonance discharge sustained by powerful millimeter wave gyrotron radiation. This device is able to produce focused D+ beams with a characteristic diameter of 1 mm, total current above 100 mA, and current density at a level of several A/cm^2. Study of such intense beams profile to obtain the best focusing efficiency and minimize neutron producing area appeared to be a challenging task. The paper also demonstrates the possibility of fast neutron imaging with a point-like powerful neutron generator (neutron yield on the level of 10^10 1/s).

physics.plasm-ph↗

arXiv2019

Study of Gasdynamic Electron Cyclotron Resonance Plasma Vacuum Ultraviolet Emission to Optimize Negative Hydrogen Ion Production Efficiency

Negative hydrogen ion sources are used as injectors into accelerators and drive the neutral beam heating in ITER. Certain processes in low-temperature hydrogen plasmas are accompanied by the emission of vacuum ultraviolet (VUV) emission. Studying the VUV radiation therefore provides volumetric rates of plasma-chemical processes and plasma parameters. In the past we have used gasdynamic ECR discharge for volumetric negative ion production and investigated the dependencies between the extracted H$^-$ current density and various ion source parameters. It was shown that it is possible to reach up to 80 mA/cm$^2$ of negative ion current density with a two electrode extraction. We report experimental studies on negative hydrogen ion production in a high-density gasdynamic ECR discharge plasma consisting of two simple mirror traps together with the results of VUV emission measurements. The VUV-power was measured in three ranges -- Ly$_α$, Lyman band and molecular continuum -- varying the source control parameters near their optima for H$^-$ production. It was shown that the molecular continuum emission VUV power is the highest in the first chamber while Ly$_α$ emission prevails in the second one. Modifications for the experimental scheme for further optimization of negative hydrogen ion production are suggested.

physics.plasm-ph↗