A. G. Popeko

A. G. Popeko
Joint Institute for Nuclear Research | jinr ОИЯИ · Flerov Laboratory of Nuclear Reactions

PhD

About

223
Publications
15,074
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
5,449
Citations
Introduction
Skills and Expertise
Additional affiliations
September 2007 - present
International University "Dubna"
Position
  • Professor (Associate)
Description
  • Lecturing in Nuclear physics, Nuclear instruments and methods
September 1968 - present
Joint Institute for Nuclear Research
Position
  • Deputy director of FLNR
Education
September 1964 - February 1970
Saint Petersburg State University
Field of study
  • physics, nuclear reactions

Publications

Publications (223)
Article
An experiment on the study of the 246Fm spontaneous fission was conducted using the SHELS separator. The isotope was synthesized in the complete fusion reaction of 40Ar beam ions and 208Pb target nuclei. The neutron yields of 246Fm spontaneous fission (ν = 3.79 ± 0.30, σν2 = 2.1) were obtained using the SFiNx detector system. The multiplicity distr...
Article
The main goal of development of the new Dubna Gas-Filled Recoil Separator (DGFRS-2) is to sufficiently improve the efficiency of studies on heavy and superheavy nuclei at the Super Heavy Element Factory of the Flerov Laboratory of Nuclear Reactions (FLNR) at the Joint Institute for Nuclear Research. The use of beams with the intensity up to 6×1013...
Preprint
Full-text available
The new neutron-deficient isotope $^{249}$No was synthesized for the first time in the fusion-evaporation reaction $^{204}$Pb($^{48}$Ca,3n)$^{249}$No. After separation, using the kinematic separator SHELS, the new isotope was identified with the GABRIELA detection system through genetic correlations with the known daughter and granddaughter nuclei...
Preprint
An experiment on the study of the $^{246}$Fm spontaneous fission was conducted using the SHELS separator. The isotope was synthesized in the complete fusion reaction of $^{40}$Ar beam ions and $^{208}$Pb target nuclei. The neutron yields of $^{246}$Fm spontaneous fission ($\overline{\nu} = 3.79\pm0.30$, $\sigma^{2}_{\nu} = 2.1$) were obtained using...
Article
The new neutron-deficient isotope 249No was synthesized for the first time in the fusion-evaporation reaction 204Pb(48Ca,3n)249No. After separation, using the kinematic separator SHELS, the new isotope was identified with the GABRIELA detection system through genetic correlations with the known daughter and granddaughter nuclei 245Fm and 241Cf. The...
Preprint
Full-text available
An analysis of recent experimental data [J. Khuyagbaatar et al., Phys. Rev. C 104, L031303 (2021)] has established the existence of two fissioning states in $^{253}$Rf: the ground state and a low-lying isomeric state, most likely involving the same neutron single-particle configurations as in the lighter isotone $^{251}$No. The ratio of fission hal...
Article
Cross section data for evaporation residues (ERs) produced in the 16O+208Pb and 48Ca+176Yb heavy-ion fusion-evaporation reactions leading to the same 224Th∗ compound nucleus (CN) were obtained at energies around the fusion reaction barriers with the recoil separator VASSILISSA. These data for ERs formed in the most probable evaporation channels in...
Article
Full-text available
A new detector system for investigating the properties of spontaneous fission of short-lived trans-uranium nuclei has been created. This system consists of an assembly of double-sided silicon strip detectors surrounded by 116 proportional neutrons counters filled with 3 He. The neutron registration efficiency is 54.7 ± 0.1%. The detector system is...
Article
Full-text available
The decay properties of states in \(^{257}\)Rf have been investigated with the detector array GABRIELA at the FLNR, Dubna. The electromagnetic decay of a new excited state in \(^{253}\)No has been observed. The state lies 750 keV above the ground state and is favourably populated in the alpha decay from a low-lying isomeric state in \(^{257}\)Rf. I...
Article
Isomeric states in No256 were investigated using internal conversion electron and γ-ray spectroscopy with the GABRIELA detection system at the focal plane of the SHELS recoil separator, at the Flerov Laboratory for Nuclear Research (FLNR, JINR, Dubna). The nuclei of interest were produced using the highly asymmetric fusion-evaporation reaction U238...
Preprint
Full-text available
The decay properties of the ground state and excited states of $^{257}$Rf have been investigated with the detector array GABRIELA at the FLNR, Dubna. The electromagnetic decay of a new excited state in $^{253}$No has been observed. The state lies 750 keV above the ground state and is favourably populated in the alpha decay of the low-lying spin iso...
Article
Full-text available
In the reaction of complete fusion of 48Ca-ions with a 204Pb target, a new α line, related to the decay of a new, previously unknown isotope (249No), has been detected in an experiment carried out at the SHELS separator. The α decay energy (E α = 9129 keV) and the half-life (T 1/2 = 38.1 ± 2.5 ms) are measured using the GABRIELA detector array. The...
Article
GABRIELA (Gamma Alpha Beta Recoil Investigations with the Electromagnetic Analyzer) is a detection system installed at the focal plane of the SHELS (Separator for Heavy Elements Spectroscopy) recoil separator for gamma and internal conversion electron spectroscopy of heavy and superheavy nuclei. GABRIELA has recently been upgraded. The characterist...
Article
Full-text available
We present new results on multi-nucleon transfer reactions in low-energy collisions of 48 Ca+ 238 U measured at the velocity filter SHIP of GSI Helmholtz Centre, where we observed around 90 different nuclides from Tl to Am (Z = 81-95). We followed the idea to use uranium targets for the synthesis of neutron-rich MNT products, particularly in the re...
Conference Paper
The GABRIELA [1] set-up is used at the FLNR to perform detailed nuclear structure studies of transfermium nuclei. Following the modernization of the VASSILISSA separator (SHELS) [2] the GABRIELA detection system has also been upgraded. The characteristics of the upgraded detection system will be presented along with results from some recent electro...
Article
The neutron yield from the spontaneous fission of the short-lived neutron-deficient ²⁵⁴Rf nucleus produced in the complete fusion reaction with the beam of multiply charged ions from the U400 accelerator at the Flerov Laboratory of Nuclear Reactions (FLNR), Joint Institute for Nuclear Research (JINR), is measured using the combined detection system...
Preprint
Full-text available
The GABRIELA [1] set-up is used at the FLNR to perform detailed nuclear structure studies of transfermium nuclei. Following the modernization of the VASSILISSA separator (SHELS) [2] the GABRIELA detection system has also been upgraded. The characteristics of the upgraded detection system will be presented along with results from some recent electro...
Article
Full-text available
The analysis of fission events following the implantation of evaporation residues produced in the fusion reaction of 50Ti and 209Bi at different bombarding energies has revealed 5 millisecond decays, which are attributed to the spontaneous fission of proton-evaporation channels. The average cross sections for proton evaporation are found to be ∼100...
Article
Using the GABRIELA (Gamma Alpha Beta Recoil Invetsigations with the ELectromagnetic Analyser) set-up [1] and SHELS recoil separator [2] the experiments aimed to the gamma and electron spectroscopy of the Fm –Db isotopes, formed at the complete fusion reactions 48Ca + 207,208Pb --> 255,256 No*, 48Ca + 209Bi --> 257Lr*, 50Ti + 206,208Pb --> 256,258 R...
Article
Full-text available
After publication of the paper, the authors noticed some errors in the affiliations. Their correct version is given in this erratum.
Article
Full-text available
In the last years we carried out several experiments aimed to investigate properties of short-lived SF isotopes. The neutron-deficient isotopes of nobelium were produced in fusion-evaporation reactions using 206,208 Pb targets and an intense 48 Ca-beam. Fusion-evaporation residues were separated by the SHELS separator and implanted into a large-are...
Article
Full-text available
The results for nuclei above curium, produced in multi-nucleon transfer reactions of ⁴⁸Ca + ²⁴⁸Cm at the velocity filter SHIP of GSI Darmstadt, are presented. Spontaneous fission and \( \alpha\)-activities have been used to study the population of nuclei with lifetimes ranging from few milliseconds to several days. We observed several, relatively n...
Article
Full-text available
The search for new decay chains of oganesson isotopes is presented. The experiment utilized the Dubna Gas Filled Recoil Separator and a highly segmented recoil-decay detection system. The signals from all detectors were analyzed in parallel by digital and analog data acquisition systems. For the first time, a target of mixed californium (51% Cf249,...
Article
series of experiments performed in 2014–2015 using the SHELS separator and a beam of multicharged ions from the U-400 accelerator at the Flerov Laboratory of Nuclear Reactions (Joint Institute for Nuclear Research) in Dubna is described. In preparation for a large program of experiments with a beam of highly charged ions of ⁵⁰Ti, an experiment is p...
Article
The structure of low-lying excited states in Fm251, populated by the α decay of No255, has been investigated by means of combined γ and internal conversion electron spectroscopy. The values for the internal conversion coefficients for the 1/2+→5/2+ and 5/2+→9/2− transitions have been measured. The determined M2/E3 mixing ratio and lifetime for the...
Article
Full-text available
We present new results from investigations of the Pu240+Ca48 reaction at a projectile energy of 250 MeV. Three new decay chains of Fl285 were detected with decay properties mostly consistent with those measured in earlier studies. An additional chain was observed where the nuclei may decay through energy levels different from those of the other six...
Conference Paper
In the last years we carried out several experiments aimed to investigate properties of short-lived SF isotopes. The neutron-deficient isotope 256Rf were produced in fusion-evaporation reactions using an 208Pb target and an intense 50Ti beam. Fusion-evaporation residues were separated by the SHELS separator (FLNR, Dubna) and implanted into a large-...
Article
This study describes an experiment on investigating the properties of spontaneous fission of shortlived neutron-deficient nuclei synthesized in the reaction of complete fusion ⁴⁸Ca + ²⁰⁴Pb = ²⁵²No*. The experiment is performed using the SHELS separator and the beam of multicharged ions at U-400 accelerator (LNR, JINR). Two activities undergoing spo...
Article
Full-text available
Recently, we reported the observation of several new isotopes with proton numbers \(Z \geq 92\) in low-energy collisions of ⁴⁸Ca + ²⁴⁸Cm . The peculiarity is that the nuclei were produced in multinucleon transfer reactions, a method which is presently discussed as a possible new way to enter so far unknown regions in the upper part of the Chart of...
Article
Spontaneous fission properties of the short-lived neutron-deficient 256Rf nucleus produced in the complete fusion reaction with a beam of multiply charged heavy 50Ti ions from the U-400 cyclotron (FLNR, JINR) are experimentally investigated. Its half-life and decay branching ratio are measured. The average number of neutrons per spontaneous fission...
Article
Full-text available
The reaction 54Cr + 248Cm was investigated at the velocity filter SHIP at GSI, Darmstadt, with the intention to study production and decay properties of isotopes of element 120. Three correlated signals were measured, which occurred within a period of 279ms. The heights of the signals correspond with the expectations for a decay sequence starting w...
Article
The SHELS velocity filter originated upon reconstruction of the VASSILISSA electrostatic separator used for investigations of heavy nuclei produced in complete fusion reactions. The goals of this modernization were to increase the transmission of products of asymmetric reactions and to extend the region of reactions to be investigated up to symmetr...
Article
Full-text available
Shell-correction energies of super-heavy nuclei are approximated by using (Formula presented.) values of measured decay chains. Five decay chains were analyzed, which start at the isotopes 285Fl, 294118, 291Lv, 292Lv and 293Lv. The data are compared with predictions of macroscopic-microscopic models. Fission barriers are estimated that can be used...
Article
The main goal of creation of a Superheavy Element Factory at the Flerov Laboratory of Nuclear Reactions (FLNR) is to sufficiently improve the efficiency of studies on heavy and superheavy nuclei. The factory will be based on a high-current DC-280 cyclotron. The use of beams with the intensity up to s−1 (10 pμA) requires effective separators providi...
Article
The goal of the DRIBs-III project is to provide more possibilities for the effective study of the properties of heavy and light exotic nuclei at the Flerov Laboratory of Nuclear Reactions. The realization of project DRIBs provides for: creation of a Superheavy Element Factory based on a high-current heavy-ion accelerator DC280, modernization of the...
Article
Detailed spectroscopic information of excited nuclear states in deformed transfermium nuclei is scarce. Most of the information available today has been obtained from investigations of fine-structure α-decay. Although α-decay gives access to hindrance factors and lifetimes which are strongly correlated to shell/subshell closures and the presence of...
Article
Full-text available
In deep inelastic multinucleon transfer reactions of 48Ca + 248Cm we observed about 100 residual nuclei with proton numbers between Z=82 and Z=100. Among them, there are five new neutron-deficient isotopes: 216U, 219Np, 223Am, 229Am and 233Bk. As separator for the transfer products we used the velocity filter SHIP of GSI while the isotope identific...
Article
Full-text available
The problem of studying the spontaneous fission of nuclei from the exotic region of short-lived neutron-deficient isotopes with Z ≥ 100 is considered. A combined detecting system is created in the focal plane of the VASSILISSA separator. The main part of this system is a neutron detector that allows us to measure the yields of spontaneous fission n...
Article
Full-text available
A new Separator for Heavy ELement Spectroscopy (SHELS) has been recently installed at the U-400 accelerator at FLNR, JINR in Dubna, Russia. The details of the upgrade as well as the results from some of the commissioning runs are discussed. In particular, transmission tests with the 208Pb(40Ar, 2-3n)245-6Fm reaction, as well as isomer spectroscopy...
Article
Over the past decade, numerous isotopes of superheavy elements with Z = 112–118 have been synthesized. Production cross sections for these species are in the range of a few picobarns (1 pb = 10−36 cm2) or less. To get access to heavier nuclides and carry out a detailed study on their properties, a sufficient increase of the overall sensitivity of e...
Article
Full-text available
Investigations of complete fusion reactions leading to the synthesis of heavy and superheavy nuclei have been an important part of the experimental program at the Flerov Laboratory of Nuclear Reactions (JINR, Dubna). For synthesis and decay studies of heavy nuclei, a project of modernization of the existing experimental set up VASSILISSA is now und...
Article
Full-text available
The results of the first experimental tests of the modernized VASSILISSA separator with the use of accelerated 22Ne ions are presented. Data has been obtained on the transmission coefficients of recoil nuclei synthesized in asymmetric combinations of the incident ion and target nuclei. Estimates from ion opti�cal calculations performed in the desig...
Article
Full-text available
U-224 nuclei were populated in fusion-evaporation reactions using a Pb-206 target and an intense Ne-22 beam. Fusion-evaporation residues were separated by the new separator SHELS at the FLNR, Dubna and implanted into a large-area double-sided silicon strip detector. Position- and time-correlated alpha decays were used to identify evaporation residu...
Article
Fission fragment mass distributions were measured in heavy-ion induced fissions using U-238 target nucleus. The measured mass distributions changed drastically with incident energy. The results are explained by a change of the ratio between fusion and qasifission with nuclear orientation. A calculation based on a fluctuation dissipation model repro...
Article
Fission fragment mass distributions were measured in heavy-ion induced fissions using 238U target nucleus. The measured mass distributions changed drastically with incident energy. The results are explained by a change of the ratio between fusion and qasifission with nuclear orientation. A calculation based on a fluctuation dissipation model reprod...
Article
Full-text available
For experiments aimed at the study of spontaneous fission of transfermium nuclei improvements in the focal plane detector system of recoil separator VASSILISSA have been made. A neutron detector consisting of 54 He-3-filled counters has been mounted around the focal-plane detector chamber. The reaction Ca-48 +Pb-206 = 2n +No-252 is used for tuning...
Article
Attempts to find superheavy elements in Nature started in the middle of sixties when predictions on the possible longevity of nuclei stabilized by the closed Z = 114-proton and N = 184-neutron shells have been made. During the ensuing years hundreds of geological samples, their processing products and probes of meteorites were studied. In all exper...
Article
Fission fragment mass distributions were measured in the heavy-ion induced fission using 238U target nucleus. The mass distributions changed drastically with incident energy. The results are explained by a change of the ratio between fusion and qasifission with nuclear orientation. A calculation based on a fluctuation dissipation model reproduced t...