Skobeltsyn Institute of Nuclear Physics
Lomonosov Moscow State University

Laboratory of the atomic collisions

The Laboratory of the atomic collisions (LAC) was organized in 1979. It is originated from a scientific group specialized in the field of acceleration of multi-charged (heavy) ions by cyclotron and studies of their interactions with matter leaded by Professor Valentin Nikolaev. Initially this group was a part of the Laboratory of nuclear reactions of SINP MSU. In 1969 it was re-organized into the Sector of the atomic collisions, which in 1979 was in turn re-organized into the Laboratory of the atomic collisions.
From 1979 till 1994 the Laboratory was headed by Professor, DSc. Valentin Nikolaev. Starting from 1994 and till present the Laboratory its Head is PhD. Yana Teplova.

The scientists of the Laboratory are specialized in the field of the studies of the basic regularities of the parameters of ions deceleration:
• the value and struggling of the particles paths;
• energy losses;
• equilibrium charge distributions and average charge of the ions;
• equilibrium thicknesses of the both gaseous and solid targets;
• cross sections of electrons losses and capture;
• production, destruction and lifetime of meta-stable ions of He- and Li-types;
• computer simulation of diffusion and channelization processes.
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These atudies are important for the development of different fields of physics (low-temperature plasma, ion sources, cosmic rays, dosimetry, interaction of the ions with matter, ion therapy).

Within the frames of the research of the Laboratory its scientists have upgraded a classical 72-cm cyclotron for acceleration of heavy ions providing thereby an opportunity for generation of stable beams of multicharged ions (from Не up to Ar, Kr).

The scientists of the Laboratory have also developed and manufactured an experimental mass-spectroscopy unit, which allows to measure charge, energy and angular distributions of the ions after collisions in gaseous media, thin films and at ions scattering from the surface in the case of grazing incidence. The unit is operated with the beam of accelerated ions of light elements within the energy range of 35-750 keV/nucleon.

Without direct measurements the scientists of the Laboratory have developed semi-empirical, theoretical and computer models which allow to interpolate and extrapolate available experimental data and to evaluate the limits of the available theoretical models validity.

The scientists of the Laboratory determined the following general properties of ion-atomic interactions for a wide set of ions with nuclear charge of Z=2-18, 36, both in basic and in metastable states, within the velocity ranges of V=(2-12)·10⁸ cm/s:
• non-monotonic dependence of paths, energy losses, cross-section for charge exchange on nucleus charge of both incident ion and target atoms, which shows the structure of the interacting particles;
• influence of the medium density on the cross-section for charge exchange;
• dependence of the number of meta-stable particles in the beam on the method of its production;
• semi-empirical relations for an average charge and width of the charge distribution of the ions in the gaseous and solid environment.

Currently the scientists of the Laboratory intend to develop physical interpretation of the processes of charge and energy state changes for fast particles in the medium, associated with structural characteristics of the particls. They measure and theoretically evaluate characteristics of the ions reflected from the surface of different targets at glazing incidence. Database on cross sections for charge exchange and charge distributions of ions are being updated. Computer simulation of the diffusion of multi-component materials taking into account influence of the surface segregation and nano-sized relief of the surface is being developed.

The research of the Laboratory is important for the control of the operation of plasma devices including diagnosis of edge plasma, simulation of charge exchange processes at interaction of the ions with matter.

The scientists of the Laboratory have published over 300 papers in Russian and foreign scientific journals, three study guides for MSU students. Data on cross sections for charge exchange, charge distributions and energy losses of the ions were collected, itegrated and published in a tabulated form.

Scientific results obtained by the scientists of the Laboratory are regularly presented at the Russian and international conferences and workshops: ICPEAC, ICACS, HCI, ECAMP etc.

The results obtained by the scientists of the Laboratory were discussed with the leading scientists in this field: Lindhard, Datz, Gilbody, McDonald, McGuire, Tavara, Kaneko, Stolterfort, Betz, Zigmund, etc.

During its existence the scientists of the Laboratory participated in over 10 commercial research projects.

Currently the Laboratory cooperate with he leading Institutes and Laboratories in this field: Kurchatov Institute, Ioffe Physical and Technical Institute (S.-Petersburg), Joint Institute of Nuclear Research (Dubna), a number of institutes participating in the Section "Atomic and electronic collisions" of RAS.