Stepanov16 февраля 1960 г.

Ведущий научный сотрудник кафедры Радиохимия Химфака МГУ с 2003 г.

Заместитель начальника отдела атомно-масштабных исследований ФГБУ ГНЦ РФ ИТЭФ.

Доцент кафедры «Физика экстремальный состояний вещества» НИЯУ МИФИ.


1977-1983 МИСиС, физико-химический факультет, каф. теорфизики. Специальность по образова-нию "Физика металлов"

1983-1986 Аспирантура ИТЭФ, специальность "Экспериментальная физика".

Ученые степени:

1987 г. Кандидат физ.-мат. наук по специальности Теоретическая и математическая физика;

2005 г. Доктор физ.-мат. наук по специальности Физика конденсированного состояния.

Ученые звания:

1995 г. Старший научный сотрудник

Общее количество – более 100, в том числе за последние 5 лет – 18

- с 2002 г. член Международного организационного комитета конференций по аннигиляции позитронов и позитрония (PPC). Переизбран в 2010 г. еще на 9 лет
- с 2013 г. член Международного организационного комитета Азиатско-тихоокеанского симпози-ума по радиационной химии (APSRC).
- с 2013 г. член Экспертного Совета по аттестации программных средств при Ростехнадзоре (сек-ция №7)

Список публикаций:

ist 1 SPIN-код: 9181-2110, AuthorID: 10249

Positions and Employment

1986 - Present:
Scientific Researcher => Senior Scientific Researcher => Deputy chief of the Low Energy Nuclear Phys-ics division => Head of physicochemical laboratory (all in the Institute of Theoretical and Experimental Physics, Moscow, Russia).

June 1993
One month stay in the Laboratory of Nuclear Chemistry, CNRS/IN2P3, Strasbourg, France

Laboratory of Physics of Condensed State, SPEC, CEA, Saclay; France

Dec.1-20, 1997; Feb.1-16, Nov.16-Dec.7 1998
Berlin Neutron Scattering Center (BENSC) in the Hahn-Meitner Institute, Berlin. Joint research project "Spin-depolarization of the polarized short-lived beta-active nuclei"

July 1 - Sept.29 1998
Nuclear Fellowship at National Institute of Materials and Chemical Research, Tsukuba, Japan “Ps for-mation in electric fields in molecular media”

May 5 - Jul.3, 1999
STA Fellowship at Japan Atomic Energy Research Institute, Tokai-Mura, Japan “PAS studies of water”

Nov.7-26, 2000
Saha Institute of Nuclear Physics, Calcutta, India “Positron and positronium states on liquids”

Jan.16-Feb.12, 2001 and May-June, 2007
Univ. Marii Curi-Skladowskoj, Lublin, Poland “Studies of alkanes by PAS”

Jan 2003 – present
Senior researcher in the Lomonosov Moscow State University, Faculty of Chemistry, Moscow, Russia. Dep. of Radiochemistry

Sep 2004 – present
Associate professor in the National Research Nuclear University MEPHI, Department of Extreme States of Matter Physics, Moscow, Russia

Other Experience and Professional Memberships
2002 - present
Member of the International scientific committee of the conferences Positron and Positronium Chemistry .

2014 - present
Member of the Expert Council on software certification (section No 7) at the Federal Environmental, In-dustrial and Nuclear Supervision Service of Russia

2005 – Award of МАИК Publisher ( ) for a series of papers “Development of the theo-ry of primary physicochemical processes in tracks of fast electrons and positrons” published in the jour-nal High energy chemistry.
1998 and 2016 -- Prizes on competitions of scientific works in ITEP
2009 -- Award of State Atomic Energy Corporation ROSATOM
2013 -- Medal “70 yeas of MEPhI” awarded by the National Research Nuclear University MEPhI .
2015 – Received the title “Veteran of Nuclear Energy and Industry” from the State Atomic Energy Cor-poration ROSATOM

Contribution to Science

1. During my post-graduate stay in ITEP Prof. F.S. Dzheparov and a member of RAS Prof. Yu.G. Abov were my scientific advisers. We investigated spin dynamics of polarized short-lived beta-active nuclei in crystals (so-called beta-NMR method). We found experimentally and explained theoretically several new effects in nuclear spin dynamics such as multi-spin nuclear resonances, magnetic reso-nance at double Larmor frequency, peculiarities of the depolarization process of beta-active nuclear probes in the disordered systems at various temperatures. From a theoretical viewpoint this activity is similar to the description of the muon-spin-rotation experiments.

While working towards my PhD in 1987 I was involved in a long-term complicated experimental pro-ject - measurement of the spin diffusion coefficient in the spatially disordered nuclear spin system of 6Li and 8Li in LiF crystals by means of beta-NMR spectroscopy. Together with Prof. F.S. Dzheparov I was responsible for elaboration of the proper theory and statistical treatment of the data.
In 1997-1998 we continued this work in the Berlin Neutron Scattering Center in the Hanh-Meitner In-stitute where I was involved in the experimental work (adjustment of the beam geometry and neutron beam collimation, electronic equipment, data acquisition).

a. Bulgakov M.I., Dzheparov F.S., Gul'ko A.D., Stepanov S.V., Shestopal V.E., Trostin S.S. "Magnetic resonance of beta-active nuclei at double Larmor frequency in LiF polycrystal with dislocations". Hyper-fine Interactions, v. 60, p.937-940, 1990. DOI: 10.1007/BF02399905

b. Yu. G. Abov, M.I. Bulgakov, S.P. Borovlev, A.D. Gul'ko, V.M. Garochkin, F.S. Dzheparov, S.V. Ste-panov, S.S. Trostin, V.E. Shestopal "Investigation of a disordered spin system of the 8Li-6Li nuclei in LiF crystals by the method of beta-NMR spectroscopy". JETP, Vol. 72, No 3, p. 534 (March 1991)

c. Yu. G. Abov, A.D. Gul'ko, F.S. Dzheparov, S.V. Stepanov, S.S. Trostin “Statistical Dynamics of the Spin Systems and b-NMR-Spectroscopy” Physics of Elementary Particles and Atomic Nuclei, V.26(6) 1654 (1995)

d. Dzheparov F.S., Gul'ko A.D., Heitjans P., L'vov D., Schirmer A., Shestopal V.E., Stepanov S.V., Tros-tin S.S. "Spin dynamics and beta-NMR after polarized neutrons capture". Physica B: Condensed Matter, v.297(1-4), p.288-292, 2001

2. Some investigations were made along the problem of an influence of extraterrestrial radiation on the natural history of the Earth. We have shown that the probability that the Earth meets a Supernova remnant in dangerous proximity during one of the Sun's passings through the Galaxy disk is about unity. Thus, the half-period, which slightly exceeds 30 million years, of the Solar system's oscillation near Ga-lactic equator plane is a natural time unit for chronologization of global geological processes and phe-nomena in the Earth history. Astronomical and astrophysical data about the structure of the Galaxy, the type of Solar system motion in it, and proper data from radiobiology, gathered here, suggest and prove the statement that the quasi-regular encounters of the Solar system with Supernova remnants are the common cause of global biological catastrophes fatally affecting primarilyy the highest, most radiosensi-tive living organisms. The results obtained show that the continuous time span (about 1 billion years), needed for evolution of the simplest forms of life to the modern ones, during which the physical condi-tions on the Earth were approximately the same as the present ones, could not be realized. It is possible to restrict this time span by a few ten million years.

We also studied role of ionizing radiation in some global geological processes on the Earth. In par-ticular, influence of ionizing radiation from radioactive nuclei disseminated in sedimentary rocks on the transformation of terrestrial organic matter into stone coals and oil.

a. Byakov V.M., Stepanov S.V., Stepanova O.P. "Quasi-Regular Staying of Solar System in Super-nova Remnants and Natural Earth History". Radiation Physics and Chemistry, v.49(3), pp.299-305, 1997. doi:10.1016/S0969-806X(96)00147-8

b. Byakov V.M., Stepanov S.V., Stepanova O.P. "Role of ionizing radiation in the natural history of the Earth". Radiation Physics and Chemistry, v.60(4-5), pp.297-301, 2001.

3. We have studied primary biological response of living organisms to the passage of fast charged particles. It is traditionally believed, that it is governed by chemical reactions of the radical products from the radiolysis of cellular water (OH, H, eaq, O2-, H2O2) and by the bioradicals that they produce. This un-derstanding has provided insight into how ionizing radiations affect biological systems and what radio-protection and radiosensibilizing effects are produced by chemical compounds introduced into an organ-ism. However, a number of key radiobiological facts remain unexplained by the current theory, stimulat-ing a search for other biologically active factors that may be triggered by radiation. We attract attention to the local increase of acidity in cellular water along the track of a charged particle. Biological processes are well-known to be highly sensitive to changes in the environmental acidity. We suggested that the biological impact of ionizing radiations is dominated not by the water radiolytic products (mostly radicals), but hydroxonium ions, H3O+ (protonated water molecules). This modification of the mechanism of primary radiobiological effects is in good agreement with experimental data. In particular, the extremal dependence of the relative biological efficiency (RBE) of radiations on their ionizing energy losses is ac-counted for in quantitative terms, as is the increase in the RBE in the relativistic energy range.

a. V.M.Byakov, S.V.Stepanov "The mechanism of the primary biological effects of ionizing radia-tion". Physics -- Uspekhi, v.49(5), 469-487 (2006)

4. In parallel with this activity, I have been working, since 1989, in the field of positron annihilation and radiation chemistry in collaboration with Prof. Vsevolod M. Byakov. A parallel investigation of early intratrack processes and formation mechanisms of Ps and Mu atoms seemed very informative and fruit-ful. We have elaborated a number of theoretical models enabling us to describe a fate of the projectile ionizing particle (e+) after its implantation into a medium, i.e. ionization slowing down, e+ and e- ther-malization, Ps formation in competition with ion-electron recombination and localization, effects of scav-engers, surfactants and application of an external electric field, formation of the Ps bubble, pick-off an-nihilation of the Ps atom, Ps (and Mu) formation in mixtures. A new version of the Ps bubble model was suggested allowing determination of the local surface tension for a very curved interphase boundaries. The results are presented on many positron and radiation chemistry meetings all over the world [see List of publications].

a. S.V. Stepanov, V.M. Byakov ``Energy loss rate and thermalization of subionizing positrons and elec-trons''. Nuclear Instruments and Methods in Physics Research B {\bf 221} 235-238, 2004

b. Stepanov S.V., Byakov V.M. "Electric field effect on Ps formation in liquids". Journal of Chemical Physics, v.116(4), pp.6178-6195, 2002.

c. S.V.Stepanov, V.M.Byakov, Y.Kobayashi "Ps Formation in Molecular Media: Effect of the External Electric Field". Phys. Rev. B, v.72(5) 054205, 2005

d. Sergey V. Stepanov, Vsevolod M. Byakov, Dmitrii S. Zvezhinskiy, Gilles Duplatre, Roman R. Nurmu-khametov and Petr S. Stepanov ``Positronium in a Liquid Phase: Formation, Bubble State and Chemical Reactions''. Advances in Physical Chemistry, vol. 2012, Article ID 431962, 17 pages, 2012.

Complete List of Published Papers:

Completed Research Support
Russian Foundation of Basic Research 11-03-01066-a 01/01/11-12/31/13
Investigation of the radiolytic processes in tracks of fast positrons on pico- and nanosecond timescale in condensed molecular media.
Role: PI

Former grants from the Russian Foundation of Basic Research 96-03-33957-а; 97-03-42617-з; 00-03-32918-а; 02-03-42632-з; 05-03-42619-з; 06-03-42727-з; 07-03-08528-з; 08-03-01105-а; 08-03-08060-з; 09-03-08005-з