Predicting the production of neutron-rich heavy nuclei in multinucleon transfer reactions using a semi-classical model including evaporation and fission competition, GRAZING-F

Yáñez, R.; Loveland, W.

doi:10.1103/physrevc.91.044608

Cited by 73 publications

(30 citation statements)

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“…For MNT reactions, semiclassical models called GRAZING [21][22][23] and Complex WKB [24] have been developed with great successes [25]. The GRAZING has recently been extended to incorporate transfer-induced fission, which is referred to as GRAZING-F [26]. To describe damped collisions, a dynamical model based on Langevin-type equations [9][10][11][12][13][27][28][29][30], the dinuclear system (DNS) model [14][15][16][17][31][32][33][34][35][36][37][38], and the improved quantum molecular dynamics model (ImQMD) [39][40][41][42][43][44] have been extensively developed.…”

Section: Introductionmentioning

confidence: 99%

Time-dependent Hartree-Fock calculations for multinucleon transfer and quasifission processes in theNi64+U238reaction

2016

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Background: Multinucleon transfer (MNT) and quasifission (QF) processes are dominant processes in lowenergy collisions of two heavy nuclei. They are expected to be useful to produce neutron-rich unstable nuclei. Nuclear dynamics leading to these processes depends sensitively on nuclear properties such as deformation and shell structure.Purpose: We elucidate reaction mechanisms of MNT and QF processes involving heavy deformed nuclei, making detailed comparisons between microscopic time-dependent Hartree-Fock (TDHF) calculations and measurements for the 64 Ni+ 238 U reaction.Methods: Three-dimensional Skyrme-TDHF calculations are performed. Particle-number projection method is used to evaluate MNT cross sections from the TDHF wave function after collision.Results: Fragment masses, total kinetic energy (TKE), scattering angle, contact time, and MNT cross sections are investigated for the 64 Ni+ 238 U reaction. They show reasonable agreements with measurements. At small impact parameters, collision dynamics depends sensitively on the orientation of deformed 238 U. In tip (side) collisions, we find a larger (smaller) TKE and a shorter (longer) contact time. In tip collisions, we find a strong influence of quantum shells around 208 Pb.Conclusions: It is confirmed that the TDHF calculations reasonably describe both MNT and QF processes in the 64 Ni+ 238 U reaction. Analyses of this system indicate the significance of the nuclear structure effects such as deformation and quantum shells in nuclear reaction dynamics at low energies.

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Section: Introductionmentioning

confidence: 99%

Time-dependent Hartree-Fock calculations for multinucleon transfer and quasifission processes in theNi64+U238reaction

2016

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“…The code has known shortcomings, i.e., when used to predict the yields of heavy fragments, it does not take into account decay by fission. (Recently Yanez and Loveland [18] have developed a modification of GRAZING called GRAZING-F which takes into account fission decay of the primary fragments, removing this deficiency.) Also, in the initial nucleus-nucleus interaction, deformation of the nuclei is not considered.…”

Section: Introductionmentioning

confidence: 99%

Xe136+Pb208reaction: A test of models of multinucleon transfer reactions

et al. 2015

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The yields of over 200 projectile-like fragments (PLFs) and target-like fragments (TLFs) from the interaction of (E c.m. =450 MeV) 136 Xe with a thick target of 208 Pb were measured using Gammasphere and off-line γ-ray spectroscopy, giving a comprehensive picture of the production cross sections in this reaction.The measured yields were compared to predictions of the GRAZING model and the predictions of Zagrebaev and Greiner using a quantitative metric, the theory evaluation factor, tef. The GRAZING model predictions are adequate for describing the yields of nuclei near the target or projectile but grossly underestimate the yields of all other products. The predictions of Zagrebaev and Greiner correctly describe the magnitude and maxima of the observed TLF transfer cross sections for a wide range of transfers (∆Z = -8 to ∆Z = +2). However for ∆Z =+4, the observed position of the maximum in the distribution is four neutrons richer than the predicted maximum. The predicted yields of the neutron-rich N=126 nuclei exceed the measured values by two orders of magnitude. Correlations between TLF and PLF yields are discussed.

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“…Semi-classical models, called GRAZING [1] and complex Wentzel-KramersBrillouin (CWKB) [2], have shown remarkable successes in describing multinucleon transfer (MNT) processes in peripheral collisions [3]. The GRAZING code was extended to include effects of transfer-induced fission in competition with particle evaporation [4]. A possible * sekizawa@if.pw.edu.pl drawback of those models lies in insufficient description of deep-inelastic processes at small impact parameters.…”

Section: Introductionmentioning

confidence: 99%

Microscopic description of production cross sections including deexcitation effects

Sekizawa

2017

Phys. Rev. C

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Background: At the forefront of the nuclear science, production of new neutron-rich isotopes is continuously pursued at accelerator laboratories all over the world. To explore the currently-unknown territories in the nuclear chart far away from the stability, reliable theoretical predictions are inevitable.Purpose: To provide a reliable prediction of production cross sections taking into account secondary deexcitation processes, both particle evaporation and fission, a new method called TDHF+GEMINI is proposed, which combines the microscopic time-dependent Hartree-Fock (TDHF) theory with a sophisticated statistical compoundnucleus deexcitation model, GEMINI++.Methods: Low-energy heavy ion reactions are described based on three-dimensional Skyrme-TDHF calculations. Using particle-number projection method, production probabilities, total angular momenta, and excitation energies of primary reaction products are extracted from the TDHF wavefunction after collision. Production cross sections for secondary reaction products are evaluated employing GEMINI++. Results are compared with available experimental data and widely-used GRAZING calculations. Results:The method is applied to describe cross sections for multinucleon transfer processes in MeV) reactions at energies close to the Coulomb barrier. It is shown that the inclusion of secondary deexcitation processes, which are dominated by neutron evaporation in the present systems, substantially improves agreement with the experimental data. The magnitude of the evaporation effects is very similar to the one observed in GRAZING calculations. TDHF+GEMINI provides better description of the absolute value of the cross sections for channels involving transfer of more than one protons, compared to the GRAZING results. However, there remain discrepancies between the measurements and the calculated cross sections, indicating a limit of the theoretical framework that works with a single mean-field potential. Possible causes of the discrepancies are discussed. Conclusions:In order to perfectly reproduce experimental cross sections for multinucleon transfer processes, one should go beyond the standard self-consistent mean-field description. Nevertheless, the proposed method will provide valuable information to optimize production mechanisms of new neutron-rich nuclei through its microscopic, non-empirical predictions.

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Predicting the production of neutron-rich heavy nuclei in multinucleon transfer reactions using a semi-classical model including evaporation and fission competition, GRAZING-F

Cited by 73 publications

References 40 publications

Time-dependent Hartree-Fock calculations for multinucleon transfer and quasifission processes in theNi64+U238reaction

Time-dependent Hartree-Fock calculations for multinucleon transfer and quasifission processes in theNi64+U238reaction

Xe136+Pb208reaction: A test of models of multinucleon transfer reactions

Microscopic description of production cross sections including deexcitation effects

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