Dubna University

Dubna, Russia

Dubna University

Dubna, Russia
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Gazizov I.M.,JSC Institute in Physical Technical Problems | Zaletin V.M.,Dubna University
IEEE Nuclear Science Symposium Conference Record | Year: 2010

The sensivity of TlBr detectors to 137Cs gamma-ray in dose rate range from 0,033 Gy/min to 3,84 Gy/min has studied in current mode. The pure and doped crystals have grown by the Bridgman-Stockbarger technique in various atmospheres: vacuum, in the vapor of bromine, in an atmosphere of hydrogen and air. Mass fraction of Pb or Ca introduced in the doped TlBr crystals was 1-10ppm and 150ppm respectively. The parameters of the carriers transport have calculated. Photocurrent measurements performed on crystal TlBr have demonstrated high sensitivity to 137Cs -radiation. The sensitivity of samples for all investigated crystals was in the range from 0,15106 C / Gy to 10106 C / Gy. Most specific sensitivity 9,0107 C / Gy mm2 at a voltage of 10 V has been obtained on the samples made of pure crystals grown in vacuum, the value of for these was found to be 4,3104 cm2 V1. The growing atmosphere and the degree of doping have a significant impact on the sensitivity TlBr samples and the dependence of the photocurrent on dose rate. The results are explained by the formation of donor-acceptor pairs associated with cationic vacancies V c and anionic Va vacancies, as well as complexes {Pb 2 Vc}, controlling recombination in TlBr. © 2010 IEEE.

News Article | February 15, 2017
Site: cerncourier.com

Tom Dombeck, an innovative and versatile physicist and project manager, passed away in Kāneʻohe, Hawaii, on 4 November 2016. His legacy includes many measurements in particle physics, the development of new techniques for the production of ultra-cold neutrons and substantial contributions to the management of several major scientific projects. Tom received a BA in physics from Columbia University in 1967 and a PhD in particle physics from Northwestern University in 1972, and his career saw him hold prominent roles at numerous institutes. He was a research associate at Imperial College London from 1972 to 1974 and visiting scientist at Dubna in the former USSR in 1975. Following six years at the University of Maryland, from 1981 to 1988 Tom held various roles at Los Alamos National Laboratory (LANL) after which he spent a year working in the US Department of Energy in the office of the Superconducting Supercollider (SSC). Afterwards he became a staff physicist and ultimately deputy project manager for operations at the SSC laboratory in Texas, where he led the successful “string test”. In 1994 he moved to a role as project manager for the Sloan Digital Sky Survey at the University of Chicago. Tom was deputy head for the technical division at Fermilab from 1997 to 1999, and project manager for the Next Linear Collider project at Fermilab between 2000 and 2002. From 2003 to 2006 he was project manager for the Pan-STARRS telescope at the University of Hawaii and an affiliated graduate faculty member there until 2016. Tom began his scientific research with bubble chambers and was a key participant in the experiment that observed the first neutrino interaction in a hydrogen filled bubble chamber in 1970 at the ZGS at Argonne National Laboratory. For many years he pursued measurements of the electric dipole moment (EDM) of the neutron and was also involved in the development of ultra-cold neutrons by Doppler shifting at pulsed sources. He proposed a new method for a neutron EDM measurement that involved Bragg scattering polarised neutrons from a silicon crystal and led an initial effort at the Missouri University Research Reactor, after which he initiated an experiment using the reactor at the NIST Center for Neutron Research. While at LANL, Tom led a neutrino-oscillation search that involved constructing a new beamline and neutrino source at LAMPF and provided improved limits on muon-neutrino to electron-neutrino oscillations. He carried these fundamental physics interests and abilities to his later work as a highly effective scientific programme manager. Tom was able to see the connections between disparate scientific areas and bring together new ideas and approaches that moved the field forwards. He could inspire people around him with his enthusiasm and kindness, and his wry sense of humour and wicked smile were trademarks that will long be remembered by his friends and colleagues. Tom was a devoted family man and is missed greatly by his wife Bonnie, his two children, Daniel and Heidi, and his four grandchildren. Sidney David Drell, professor emeritus of theoretical physics at SLAC National Accelerator Laboratory, senior fellow at Stanford’s Hoover Institution and a giant in the worlds of both academia and policy, died on 21 December 2016 at his home in Palo Alto, California. He was 90 years old. Drell made immense contributions to his field, including uncovering a process that bears his name and working on national and international security. His legacy as a humanitarian includes his friendship and support of Soviet physicist and dissident Andrei Sakharov, who won the Nobel Peace Prize in 1975 for his opposition of the abuse of power in the Soviet Union. Drell was also known for his welcoming nature and genuine, albeit perhaps unwarranted, humility. Drell’s commitment to arms control spanned more than 50 years. He served on numerous panels advising US Congress, the intelligence community and military. He was an original member of JASON, a group of academic scientists created to advise the government on national security and defence issues, and from 1992 to 2001 he was a member of the President’s Foreign Intelligence Advisory Board. He was also the co-founder of the Center for International Security and Cooperation at Stanford, and in 2006 he and former Secretary of State George Shultz began a programme at the Hoover Institution dedicated to developing practical steps towards ridding the world of nuclear weapons. In 1974, Drell met Sakharov at a conference hosted by the Soviet Academy of Sciences and they quickly became friends. When Sakharov was internally exiled to Gorky from 1980 to 1986 following his criticism of the Soviet invasion of Afghanistan, Drell exchanged letters with him and called on Soviet leader Mikhail Gorbachev for his release. He also organised a petition to allow another Soviet physicist and dissident, Nohim Meiman, to emigrate to Israel, and obtained the signatures of 118 members of the US National Academy of Sciences. Having graduated with a bachelor’s degree from Princeton University in 1946, Drell earned a master’s degree in 1947 and a PhD in physics in 1949 from the University of Illinois, Urbana-Champaign. He began at Stanford in 1950 as an instructor in physics, leaving to work as a researcher and assistant professor at the Massachusetts Institute of Technology and then returning to Stanford in 1956 as a professor of physics. He served as deputy director of SLAC from 1969 until his retirement from the lab in 1998. Drell’s research was in the fields of quantum electrodynamics and quantum chromodynamics. While at SLAC, he and research associate Tung-Mow Yan formulated the famous Drell–Yan Process, which has become an invaluable tool in particle physics. His theoretical work was critical in setting SLAC on the course that it took. As head of the SLAC theory group, Drell brought in a host of younger theoretical physicists who began creating the current picture of the structure of matter. He played an important role in developing the justification for experiments and turning the results into what became the foundation of the Standard Model of particle physics. For his research and lifetime of service to his country, Drell received many prestigious awards, including: the National Medal of Science; the Enrico Fermi Award; a fellowship from the MacArthur Foundation; the Heinz Award for contributions in public policy; the Rumford Medal from the American Academy of Arts and Sciences; and the National Intelligence Distinguished Service Medal. Drell was one of 10 scientists honoured as the founders of satellite reconnaissance as a space discipline by the US National Reconnaissance Office. He was elected to the National Academy of Sciences, the American Academy of Arts and Sciences and the American Philosophical Society, and was president of the American Physical Society in 1986. Drell was also an accomplished violinist who played chamber music throughout his life. He is survived by his wife, Harriet, and his children, Daniel, Virginia, Persis and Joanna. Persis Drell, a former director of SLAC who is also a physicist at Stanford and dean of the School of Engineering, will be the university’s next provost. • Based, with permission, on the obituary published on the Stanford University website on 22 December 2016. Mambillikalathil Govind Kumar Menon, a pioneer in particle physics and a distinguished statesman of science, passed away peacefully on 22 November at his home in New Delhi, India. He graduated with a bachelor of science from Jaswant College, Jodhpur, in 1946, and inspired by Chandrasekhara Venkata Raman, studied under the tutelage of spectroscopist Nanasaheb R Tawde before joining Cecil Powell’s group at the University of Bristol, UK, in 1949. Menon’s first important contribution was to establish the bosonic character of the pion through a study of fragments emerging from π-capture by light nuclei. He then focused his attention on the emerging field of K-meson physics. Along with his colleagues at Bristol, notably Peter Fowler, Cecil Powell and Cormac O’Ceallaigh, Menon discovered K+ → π+ π0 and K+ → π+ π– π+ events in nuclear emulsion indicating parity non-conservation, (the τ – θ puzzle). He also identified a sizeable collection of events showing the associated production of kaons and hyperons. In 1955 Menon joined the Tata Institute of Fundamental Research (TIFR), where he worked on cosmic-ray research programmes initiated by Homi Bhabha. Following Bhabha’s death in an air crash over Mont Blanc in 1966, the responsibility of the directorship of TIFR fell squarely on his shoulders, along with the wide-ranging initiatives for national development that Bhabha had started. Notwithstanding these additional demands on his time, his focus on particle physics never wavered. He continued with his research, establishing a collaboration with Arnold W Wolfendale at the University of Durham, UK, and Saburo Miyake of Osaka City University, Japan, for the study of particle physics with detectors deployed deep underground; he detected events induced by cosmic-ray neutrino interactions; and he also launched a dedicated effort to test the early predictions of violation of baryon-number conservation leading to proton decay. During his Bristol years, Menon established a close friendship with William O Lock, who had moved to CERN in 1959. This facilitated collaboration between TIFR and CERN, leading to the development of bubble-chamber techniques to study mesons produced in proton–antiproton collisions. These initial studies eventually led to highly successful collaborations between Indian researchers and the L3 experiment at LEP, and the CMS, ALICE and ATLAS experiments at the LHC. Menon won several awards including the Cecil F Powell and C V Raman medals, and was elected to the three scientific academies in India. He was elected as a fellow of the Royal Society in 1970, and subsequently to the Pontifical Academy of Sciences, American Academy of Arts and Sciences, the Russian Academy of Sciences and as an honorary fellow of the Institute of Physics and the Institution of Electrical & Electronics Engineers. He also served two terms as president of the International Council of Scientific Unions, and stimulated its participation in policy issues, including climate change. Menon held a firm conviction that science can bring about technological development and societal progress, which motivated him to work with Abdus Salam in founding the Third World Academy of Sciences. He held several high positions in the Indian government, and thus contributed to the growth of science and technology in India. Alongside his scientific achievements, M G K Menon was also very close to his wife Indumati and their two children Preeti and Anant Kumar. Our warmest thoughts go out to them and to innumerable others whose lives he touched in so many important ways. Helmut Oeschler, an active member of the ALICE collaboration, passed away from heart failure on 3 January while working at his desk. Born in Southern Germany, he received his PhD from the University of Heidelberg in 1972 and held postdoc positions at the Niels Bohr Institute in Copenhagen, and in Strasbourg, Saclay and Orsay in France. From 1981 he was at the Institute for Nuclear Physics of TU Darmstadt. He held a Doctorate Honoris Causa from Dubna University, Russia, and in 2006 he received the Gay-Lussac-Humboldt prize. Oeschler’s physics interests concerned the dynamics of nuclear reactions over a broad energy range, from the Coulomb barrier to ultra-relativistic collisions. He was a driving force for building the kaon spectrometer at the GSI in Darmstadt, which made it possible to measure strange particles in collisions of heavy nuclei. From the late 1990s he was actively involved in addressing new aspects of equilibration in relativistic nuclear reactions. Oeschler became a member of the ALICE collaboration at CERN in 2000 and made important contributions to the construction of the experiment. Together with his students, he was involved in developing track reconstruction software for measuring the production of charged particles in lead–lead collisions at the LHC. He also led the analysis efforts for the measurements of identified charged hadrons in the LHC’s first proton–proton collisions. From 2010 to 2014 he led the ALICE editorial board, overseeing the publication of key results relating to quark-gluon matter at the highest energy densities. His deep involvement in the data analysis and interpretation continued unabated and he made important contributions to several research topics. Advising and working in close collaboration with students was a much loved component of Helmut’s activity and was highly appreciated among the ALICE collaboration. Helmut Oeschler was a frequent visitor of South Africa and served there on numerous international advisory committees. He was instrumental in helping the South African community develop the physics of heavy-ion collisions and collaboration with CERN. With Helmut Oeschler we have lost an internationally renowned scientist and particular friend and colleague. His scientific contributions, especially on the production of strange particles in high-energy collisions, are important achievements.

Volkov M.K.,Joint Institute for Nuclear Research | Arbuzov A.B.,Dubna University | Kostunin D.G.,Karlsruhe Institute of Technology
Physical Review C - Nuclear Physics | Year: 2014

The process of electron-positron annihilation into η(η′)2π is described within the extended Nambu-Jona-Lasinio model in the energy range up to about 2 GeV. Contributions of intermediate vector mesons ρ(770) and ρ(1450) are taken into account. Results for the η2π channel are found to be in a reasonable agreement with experimental data. Predictions for production of η′2π are given. The corresponding estimations for decays τ→η(η′)2πν are given in the Appendix. © 2014 American Physical Society.

Martynov Y.B.,Institute of Applied Acoustics | Nazmitdinov R.G.,University of the Balearic Islands | Nazmitdinov R.G.,Joint Institute for Nuclear Research | Tanachev I.A.,Dubna University | Gladyshev P.P.,Dubna University
JETP Letters | Year: 2012

We show that narrow optical band pass filters can be created by means of nanoparticles which consist of a dielectric sphere and a metallic shell. The components can be adjusted such that there is a remarkable transparency at the desired wavelength range, while a strong absorption takes place outside of this region. © 2012 Pleiades Publishing, Ltd.

Bening V.E.,Russian Academy of Sciences | Korolev V.Y.,Russian Academy of Sciences | Savushkin V.A.,Dubna University | Zeifman A.I.,Russian Academy of Sciences
AIP Conference Proceedings | Year: 2015

In the paper we consider asymptotic deficiencies of some estimators based on the samples with random sizes. The case of the Poisson distribution is investigated. © 2015 AIP Publishing LLC.

Gazizov I.M.,Institute for Physico Technical Problems | Zaletin V.M.,Dubna University | Kukushkin V.M.,Institute for Physico Technical Problems | Khrunov V.S.,Institute for Physico Technical Problems
Semiconductors | Year: 2011

The current response of a TlBr detector to 137Cs γ-ray radiation has been studied in the dose-rate range 0.033-3.84 Gy/min and within the voltage range 1-300 V; the detectors are based on pure and doped TlBr crystals grown from the melt by the Bridgman-Stockbarger method. The mass fraction of Pb or Ca introduced into the TlBr crystals was 1-10 ppm for Pb and 150 ppm for Ca. The current response of nominally undoped TlBr samples was nearly linear over two decades of studied dose rates. Deep hole levels associated with cationic vacancies Vc - determine the dependence of the current response on the voltage in the high electric fields. The parameters of the carriers' transport μτ are determined. The TlBr crystals grown in vacuum and in the bromine vapor exhibit a large mobility-lifetime product of 4.3 × 10-4 and 6.4 × 10-5 cm2V-1, respectively. The value of μτ is in the range (4-9) × 10-5 cm2V-1 for crystals doped with a divalent cation. © 2011 Pleiades Publishing, Ltd.

Kalinin A.Y.,RAS Research Center Kurchatov Institute | Kokovin V.A.,Dubna University | Kryshkin V.I.,RAS Research Center Kurchatov Institute | Skvortsov V.V.,RAS Research Center Kurchatov Institute
Instruments and Experimental Techniques | Year: 2016

Based on fast gas electron multipliers, a beam monitor and recording electronics for reading information and transmitting it to the local network was manufactured. The speed of operation of the system is determined by the characteristics of driver amplifiers and equal to ~108 (particle/s)/cm2. The operation of the system was tested from a radioactive source. © 2016, Pleiades Publishing, Inc.

Shukrinov Y.M.,Dubna University | Azemtsa-Donfack H.,University of South Africa | Rahmonov I.R.,Umarov Physical Technical Institute | Botha A.E.,University of South Africa
Low Temperature Physics | Year: 2016

We found that the coupled system of Josephson junctions under external electromagnetic radiation demonstrates a cascade of parametric instabilities. These instabilities appear along the IV characteristics within bias current intervals corresponding to Shapiro step subharmonics and lead to charging in the superconducting layers. The amplitudes of the charge oscillations increase with increasing external radiation power. We demonstrate the existence of longitudinal plasma waves at the corresponding bias current values. An essential advantage of the parametric instabilities in the case of subharmonics is the lower amplitude of radiation that is needed for the creation of the longitudinal plasma wave. This fact gives a unique possibility to create and control longitudinal plasma waves in layered superconductors. We propose a novel experiment for studying parametric instabilities and the charging of superconducting layers based on the simultaneous variation of the bias current and radiation amplitude.

Perepelkin E.E.,Moscow State University | Sadovnikov B.I.,Moscow State University | Inozemtseva N.G.,Dubna University
Journal of Statistical Mechanics: Theory and Experiment | Year: 2015

A derivation of the first Vlasov equation as a well-known Schrödinger equation for the probabilistic description of a system and families of the classic diffusion equations and heat conduction for the deterministic description of physical systems was inferred. A physical meaning of the phase of the wave function which is a scalar potential of the probabilistic flow velocity is demonstrated. Occurrence of the velocity potential vortex component leads to the Pauli equation for one of the spinar components. A scheme for the construction of the Schrödinger equation solution from the Vlasov equation solution and vice-versa is shown. A process of introduction of the potential to the Schrödinger equation and its interpretation are given. The analysis of the potential properties gives us the Maxwell equation, the equation of the kinematic point movement, and the equation for movement of the medium within electromagnetic fields. © 2015 IOP Publishing Ltd and SISSA Medialab srl.

Inozemtseva N.G.,Dubna University | Maslennikov I.I.,Moscow State University | Sadovnikov B.I.,Moscow State University
Moscow University Physics Bulletin | Year: 2013

The purpose of this paper is to study the asymptotic properties of time autocorrelation functions for the generalized nonlinear Boltzmann-Enskog model, which contains a long-range component of the interaction between the particles. On the basis of the analysis of non-linear features of the Boltzmann-Enskog kinetic equation, the role of nonlinear effects is directly revealed at the approach to an equilibrium state. It is shown that autocorrelation functions have power asymptotics t -3/2, and the effects that are related to the inclusion of the long-range component lead to a change in the coefficient at t -3/2. These results establish a closed expression for the determination of coefficients in the asymptotic expansion of the autocorrelation functions of rate and thermal diffusion. © 2013 Allerton Press, Inc.

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