2019, Hwangbo, D., Kajita, S., Ohno, N., Sinelnikov, D., Bulgadaryan, D., Kurnaev, V., Синельников, Дмитрий Николаевич

© 1973-2012 IEEE.Field emission from tungsten surfaces with nano-tendril bundles formed after exposure to helium plasma with nitrogen or neon impurities was measured using a vacuum diode device. Field enhancement factor and effective emission area were calculated using the Fowler-Nordheim formula and compared for different types of nanostructures. The field enhancement factor for these structures can reach several thousands and the effective emission area can be more than 1000 nm2. Anode luminescence was detected using long-exposure photography and allowed for estimation of current density near the anode. Unipolar arc tracks were observed on the samples with the highest field emission intensity. We show that field emission from nano-tendril bundles is much higher than that from tungsten fuzz or pure tungsten, and fusion-relevant plasma conditions may lead to arc initiation.

2019, Bulgadaryan, D., Sinelnikov, D., Kurnaev, V., Efimov, N., Borisyuk, P., Lebedinskii, Y., Синельников, Дмитрий Николаевич, Ефимов, Никита Евгеньевич, Борисюк, Петр Викторович, Лебединский, Юрий Юрьевич

© 2018 Elsevier B.V. Hydrogen ions are not widely used in low or medium-energy ion scattering spectroscopy. However, in certain cases, the use of non-destructive hydrogen ions with low nuclear stopping may provide additional information compared with noble gas ions. In this work, we describe in situ analysis of nanometer layer deposition of Au on Si and vice versa using keV-energy proton scattering spectroscopy. Ion beam sputtering and thermal evaporation were used for deposition of surface layers. The maximum thickness of deposited layers was measured with X-ray photoelectron spectroscopy and surface profiler. The accuracy of in situ surface layer thickness determination with energy spectra of scattered protons is discussed.

2019, Sinelnikov, D., Bulgadaryan, D., Buyanov, G., Синельников, Дмитрий Николаевич, Буянов, Григорий Олегович

© Published under licence by IOP Publishing Ltd.Periodic discharge in water flow was investigated using optic spectrometer and 1000 fps video camera with the discharge pulse up to several milliseconds long regulated by water flow speed. Copper drops were found on the cathode surface in the case of copper-tube anode. In spite of water cooling anode can reach melting point. Optic spectra were compared for several materials of electrodes. For copper electrodes it was found that anode is the main contributor of copper in discharge plasma.

2019, Mamedo, N. V., Kurnaev, V. A., Sinelnikov, D. N., Mamedov, I. M., Синельников, Дмитрий Николаевич, Мамедов, Никита Вадимович

Low-energy (1-20 keV) ion scattering spectroscopy is the widespread method of surface analysis [1,2]. The surface layer composition can be reconstructed from narrow peaks in the energy spectra of the scattered inert gas ions and recoil ions [3]. The main advantage of the surface analysis using inert gas ions is the high sensitivity to the first layer of surface atoms. This is due to the low initial energy of the ions (and therefore small ion penetration depth) and the high neutralization probability of the reflected ions, which increases with the penetration depth of the incident particle into the solid [3]. However, for quantitative surface analysis, it is extremely important to determine the neutralization probability (or the probability of ion survival), since this method usually detects reflected ions only.

2017, Mamedov, N. V., Kurnaev, V. A., Sinelnikov, D. N., Kolodko, D. V., Sorokin, I. A., Мамедов, Никита Вадимович, Колодко, Добрыня Вячеславич, Синельников, Дмитрий Николаевич, Сорокин, Иван Александрович

The adsorption of water on the surface is one of the main problems in vacuum technology. Since water is a good adsorbent, its adsorption is the reason that prevents the fast pumping of vacuum systems up to ultra-high vacuum. In addition, water vapor adsorption on metal surfaces during plasma surface interaction is a problem [1]. Singly scattered and recoil ions could form narrow peaks in energy spectra and provide information about atomic composition of the first atomic layer giving information about structure and composition of the surface and very sensitivity to the first layer of atoms [2 -5]. It was also shown [6] that the thickness of light element thin layers on the heavy substrate can be analyzed with good depth resolution (~0,3nm) due to scattering of hydrogen ions with keV energies. Application of ion scattering spectroscopy at pressures up to several mTorr is presented in [7, 8]. In this work experimental results of low energy ion spectroscopy (LEIS) of W samples during water vapor adsorption are presented.

2019, Bulgadaryan, D., Sinelnikov, D., Kurnaev, V., Efimov, N., Ефимов, Никита Евгеньевич, Синельников, Дмитрий Николаевич

Low- and medium-energy ion scattering (LEIS/MEIS) are widely used techniques of surface analysis [1–4]. Conventional LEIS/MEIS setups utilize noble gas ions and electrostatic energy analyzers that makes these methods very sensitive to composition of the uppermost atomic layers of an analyzed sample. However, high neutralization probability of noble gas ions restricts LEIS/MEIS depth profiling capabilities [5]. The use of hydrogen ions with lower neutralization probability instead of noble gas provides possibility to measure the thickness of surface layer if its atomic mass is very different from that of underlying target, that is the case e.g. in nanoelectronics [6] or for redeposition of plasma-facing materials in fusion devices [7]. In this work we present simulated and experimental data on implementation of keV-energy proton scattering (KEPS) for surface analysis.

2019, Bulgadaryan, D. G., Sinelnikov, D. N., Sorokin, I. A., Kurnaev, V. A., Efimov, N. E., Синельников, Дмитрий Николаевич, Сорокин, Иван Александрович, Ефимов, Никита Евгеньевич

© 2019, Pleiades Publishing, Ltd.The erosion and redeposition processes of plasma-facing materials in fusion devices are the most important factors affecting near-wall and core plasma parameters and device lifetime. To determine the possibility of in situ analyzing these processes, we developed an experimental model of a built-in surface analyzer utilizing low-energy proton scattering spectroscopy. The results of experimental approbation of the method are presented.