0000000000276889
AUTHOR
T. Loktev
Effects of weakly coupled channels on quasielastic barrier distributions
Heavy-ion collisions often produce fusion barrier distributions with structures displaying a fingerprint of couplings to highly collective excitations. Similar distributions can be obtained from large-angle quasielastic scattering, although in this case, the role of the many weak direct-reaction channels is unclear. For $^{20}\mathrm{Ne}+^{90}\mathrm{Zr}$, we have observed the barrier structures expected for the highly deformed neon projectile; however, for $^{20}\mathrm{Ne}+^{92}\mathrm{Zr}$, we find significant extra absorption into a large number of noncollective inelastic channels. This leads to smearing of the barrier distribution and a consequent reduction in the ``resolving power'' o…
Production and investigation of neutron-rich Osmium isotopes with and around N=126 using gas flow transport method
Neutron-rich isotopes of heavy nuclei are until now poorly studied. In this work we investigate neutron-rich osmium isotopes produced in multi-nucleon transfer reactions. The reaction 136Xe+208Pb at energy near Coulomb barrier is used for production of osmium isotopes. The CORSAR-V setup is used to record the characteristics of osmium isotopes. The separation of the reaction products is based on their respective volatility. Experimental results are presented and discussed. © Published under licence by IOP Publishing Ltd.
The study of neutron-rich nuclei production in the region of the closed shell N=126 in the multi-nucleon transfer reaction 136Xe+208Pb
Expérience LNL/PRISMA; International audience; The unexplored area of heavy neutron rich nuclei is extremely important for nuclearastrophysics investigations and, in particular, for the understanding of the r-process ofastrophysical nucleogenesis. For the production of heavy neutron rich nuclei located along theneutron closed shell N=126 (probably the last "waiting point" in the r-process of nucleosynthesis)the low-energy multi-nucleon transfer reaction 136Xe+208Pb at Elab=870MeV was explored.Due to the stabilizing eect of the closed neutron shells in both nuclei, N=82 and N=126, andthe rather favorable proton transfer from lead to xenon, the light fragments formed in this processare well b…
Weak channels in backscattering of20Ne onnatNi,118Sn, and208Pb
To further our understanding of the influence of weakly coupled channels on the distribution of Coulomb barrier heights, we have measured transfer cross sections for ${}^{20}$Ne ions backscattered from ${}^{\mathrm{nat}}$Ni, ${}^{118}$Sn, and ${}^{208}$Pb targets at near-barrier energies. The $Q$ value spectrum in the case of ${}^{208}$Pb target has been determined too. The transfer channels appear to be especially important for ${}^{208}$Pb, whose double-closed-shell nature leads to a relatively low level density for noncollective inelastic excitations.
Shell effects in damped collisions ofSr88withYb176at the Coulomb barrier energy
This work is a study of the influence of shell effects on the formation of binary fragments in damped collision. We have investigated binary reaction channels of the composite system with $Z=108$ produced in the reaction $^{88}\mathrm{Sr}$${+}^{176}$Yb at an energy slightly above the Bass barrier (${E}_{\text{c.m.}}/{E}_{\text{Bass}}=1.03$). Reaction products were detected by using the two-arm time-of-flight spectrometer CORSET at the K130 cyclotron of the Department of Physics, University of Jyv\"askyl\"a. The mass-energy distribution of primary binary fragments has been measured. For targetlike fragments heavier than 190 u, which correspond to a mass transfer as large as twenty nucleons o…
Investigation of the reaction 64Ni+238U being an option of synthesizing element 120
This study is concerned with the search for entrance channels suitable to synthesize elements with Z > 118. Mass-energy distributions as well as capture cross-sections of fission-like fragments have been measured for the reactions 64Ni + 238U → 302120 and 48Ca + 238U → 286112 at energies near the Coulomb barrier. Compound nucleus fission cross-sections were estimated from the analysis of mass and total kinetic energy distributions. The cross-section drops three orders of magnitude for the formation of the compound nucleus with Z = 120 obtained in the reaction 64Ni + 238U compared to the formation of the compound nucleus with Z = 112 obtained in the reaction 48Ca + 238U at an excitation ener…
The fusion-fission process in the reaction 34S+186W near the interaction barrier
International audience; The reaction 34S + 186W at Elab=160 MeV was investigated with the aim of diving into the features of thefusion-fission process. Gamma rays in coincidence with binary reaction fragments were measured using the high efficiencygamma-ray spectrometer ORGAM at the TANDEM Accelerator facility of I.P.N., Orsay, and the time-of-flight spectrometerfor fission fragments (FF) registration CORSET of the Flerov Laboratory of Nuclear Reactions (FLNR), Dubna. The couplingof the ORGAM and CORSET setups offers the unique opportunity of extracting details for characterizing the fusion-fissionprocess and gives information regarding production of neutron-rich heavy nuclei. The FF-$\gamm…
Mass distributions of the system136Xe+208Pb at laboratory energies around the Coulomb barrier: A candidate reaction for the production of neutron-rich nuclei atN=126
Reaction products from the system ${}^{136}\mathrm{Xe}+{}^{208}$Pb at ${}^{136}$Xe ions laboratory energies of 700, 870, and 1020 MeV were studied by two-body kinematics and by a catcher-foil activity analysis to explore the theoretically proposed suitability of such reaction as a means to produce neutron-rich nuclei in the neutron shell closure $N=126$. Cross sections for products heavier than ${}^{208}$Pb were measured and were found sensibly larger than new theoretical predictions. Transfers of up to 16 nucleons from Xe to Pb were observed.
Weak channels in backscattering of ^{20}Ne on ^{nat}Ni, ^{118}Sn, and ^{208}Pb
To further our understanding of the influence of weakly coupled channels on the distribution of Coulomb barrier heights, we have measured transfer cross sections for 20Ne ions backscattered from natNi, 118Sn, and 208Pb targets at near-barrier energies. The Q value spectrum in the case of 208Pb target has been determined too. The transfer channels appear to be especially important for 208Pb, whose double-closed-shell nature leads to a relatively low level density for noncollective inelastic excitations. peerReviewed