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Dubna, Russia
Dubna, Russia
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Tsyganov Y.S.,FLNR
Physics of Particles and Nuclei Letters | Year: 2016

With reaching extremely high intensities of heavy-ion beams, new requirements for the detection system of the Dubna Gas-Filled Recoil Separator (DGFRS) will definitely be set. One of the challenges is how to apply the “active correlations” method [1–6] to suppress beam associated background products without significant losses in the whole long-term experiment efficiency value. Different scenarios and equations for the development of a method according to this requirement are under consideration in the present paper. © 2016, Pleiades Publishing, Ltd.


Rymzhanov R.A.,FLNR | Medvedev N.A.,German Electron Synchrotron | Volkov A.E.,RAS Research Center Kurchatov Institute
Physica Status Solidi (B) Basic Research | Year: 2015

The presented Monte Carlo model simulates excitation of the electron subsystem of semiconductors by a penetrating swift heavy ion (SHI). The cross sections of interaction of an ion with the electron subsystem of a target are calculated via the complex dielectric function formalism, which accounts for all the collective modes of the electron ensemble of the target. The predicted electron inelastic mean free paths are in a very good agreement with those from the NIST database. The calculated SHI energy losses coincide well with SRIM and CasP codes. The model is used to calculate the spectra of electrons emitted from germanium and silicon targets during SHI irradiation. These spectra agree well with the experimental data. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Rymzhanov R.A.,FLNR | Medvedev N.A.,German Electron Synchrotron | Volkov A.E.,RAS Research Center Kurchatov Institute
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2015

A considerable part of the excess energy of the electronic subsystem of a solid penetrated by a swift heavy ion (SHI) is accumulated in valence holes. Spatial redistribution of these holes can affect subsequent relaxation, resulting in ionizations of new electrons by hole impacts as well as energy transfer to the target lattice. A new version of the Monte Carlo code TREKIS is applied to study this effect in Al2O3 for SHI tracks. The complex dielectric function (CDF) formalism is used to calculate the cross sections of interaction of involved charged particles (an ion, electrons, holes) with the target giving us ability to take into account collective response of a target to excitations. We compare the radial distributions of the densities and energies of excited electrons and valence holes at different times to those obtained under the assumption of immobile holes used in earlier works. The comparison shows a significant difference between these distributions within the track core, where the majority of slow electrons and valence holes are located at femtosecond timescales after the ion impact. The study demonstrates that the energy deposited by valence holes into the lattice in nanometric tracks is comparable to the energy transferred by excited electrons. Radii of structure transformations in tracks produced by these energy exchange channels are in a good agreement with experiments. © 2015 Elsevier Inc. All rights reserved.


Rymzhanov R.A.,FLNR | Medvedev N.A.,German Electron Synchrotron | Volkov A.E.,RAS Research Center Kurchatov Institute
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2015

An effect of different phase states of a solid on excitation of its electronic subsystem due to penetration of a swift heavy ion (SHI) is examined on example of silicon dioxide (crystalline quartz vs. amorphous glass). The complex dielectric function formalism describing collective response of the electronic and ionic subsystems of a condensed target to excitation is used to calculate scattering cross sections of a penetrating ion and electrons generated due to target ionizations. A Monte Carlo model based on these cross sections is applied for tracing electron kinetics in the nanometric vicinity of the trajectory of a swift heavy ion. It is demonstrated that differences of the maximal values of the SHI energy losses and the electron inelastic mean free paths calculated for two phase states of SiO2 do not exceed 10-15%, whereas the elastic mean free paths differ more significantly. © 2014 Elsevier B.V. All rights reserved.


Tsyganov Y.S.,FLNR
Physics of Particles and Nuclei Letters | Year: 2016

With reaching to extremely high intensities of heavy-ion beams new requirements for the detection system of the Dubna Gas-Filled Recoil Separator (DGFRS) will definitely be set. One of the challenges is how to apply the “active correlations” method to suppress beam associated background products without significant losses in the whole long-term experiment efficiency value. Different scenarios and equations to develop the method according this requirement are under consideration in the present paper. The execution time to estimate the dead time parameter associated with the optimal choice of the life-time parameter is presented. © 2016, Pleiades Publishing, Ltd.


Tsyganov Y.S.,FLNR
Physics of Particles and Nuclei Letters | Year: 2015

Real-time PC based algorithm is developed for DSSSD (Double Side Silicon Strip Detector) detector. Brief description of the detection system is also presented. Complete fusion nuclear reaction natYt + 48Ca → 217Th is used to test this algorithm at 48Ca beam. Example of successful application of a former algorithm for resistive strip PIPS (resistive strip Passivated Implanted Planar Silicon) detector is presented too. © 2015, Pleiades Publishing, Ltd.


Tsyganov Y.S.,FLNR
Physics of Particles and Nuclei Letters | Year: 2015

A new real-time PC based algorithm and a compact C++ code to operate in a real-time mode with a 48 × 128 strip double side position sensitive large area silicon radiation detector Micron Semiconductors (UK) are developed and tested. Namely with this new approach it has become possible to provide the quick extraction of EVR-alpha correlated sequences in heavy ion induced complete fusion nuclear reactions. Specific attention is paid to the application of new CAMAC 4 M modules for charge particle position measurement during long-term experiments aimed to the synthesis of new superheavy nuclei. Some attention is paid to the different (combined) algorithm scenario to search for ER-alpha and alpha-alpha chains. © 2015, Pleiades Publishing, Ltd.


Yamauchi Yu.,FLNR | Apel P.Yu.,FLNR
Journal of Physics: Conference Series | Year: 2010

The use of surfactants in etching of the track membranes (TMs) enables one to control the pore shape in TMs. This technique is useful to improve flow rate, and to optimize the retention and permeation properties of TMs. The addition of an anionic surfactant, sodium dodecyl diphenyloxide disulphonate (SDDD), to etching solutions leads to the highly tapered pore shape in TMs of the polyethylene terephthalate (PET). To understand the mechanism of the surfactant effect on track etching in the nanometer range, we study the diffusion and adsorption of SDDD on non-etched non-porous, etched non-porous and etched porous PET films. The comparison of non-etched non-porous and etched non-porous films shows the effect of negatively charged surface on the adsorption of surfactant. The comparison of etched non-porous and etched porous PET films shows the different adsorption on film surface and inner wall of nanopore, thus the influence of curvature of the surface on the adsorption of surfactant molecules. © 2010 IOP Publishing Ltd.


Tsyganov Y.,FLNR
AIP Conference Proceedings | Year: 2010

During the recent years, at the FLNR (JINR) a successful cycle of experiments has been accomplished on the synthesis of the superheavy elements with Z=112 -118 with 48Ca beam. From the viewpoint of the detection of rare decays and background suppression, this success was achieved due to the application of a new radical technique - the method of active correlations. The method employs search in a real -time mode for a pointer to a probable correlation like recoil-alpha for switching the beam off. In the case of detection in the same detector strip an additional alpha -decay event, of "beam OFF" time interval is prolonged automatically. © 2010 American Institute of Physics.


Tsyganov Y.S.,FLNR
Physics of Particles and Nuclei Letters | Year: 2014

A new approach to provide a fruitful analysis of signal amplitude is proposed. It is this method that has made it possible to eliminate some observed artificial events from the list of candidates for decays of superheavy nuclei. Examples of estimates of measured amplitudes of evaporation residues (EVR) are presented. Some attention is paid to a new “hard” statistical criterion for detecting rare events. © 2014, Pleiades Publishing, Ltd.

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