Experimental studies of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mrow /><mml:mn>249</mml:mn></mml:msup></mml:math>Bk + <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mrow /><mml:mn>48</mml:mn></mml:msup></mml:math>Ca reaction including decay properties and excitation function for isotopes of element 117, and discovery of the new isotope<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:m

Oganessian, Yu. Ts.; Abdullin, F. Sh.; Alexander, C.W.; Binder, Jeffrey L.; Boll, R. A.; Dmitriev, S. N.; Ezold, Julie G.; Felker, Kevin; Gostic, J. M.; Grzywacz, R.; Hamilton, J. H.; Henderson, R. A.; Иткис, М. Г.; Miernik, K.; Miller, D.; Moody, K. J.; Polyakov, A. N.; Ramayya, A. V.; Roberto, J. B.; Ryabinin, M. A.; Rykaczewski, K. P.; Sagaidak, R. N.; Shaughnessy, D. A.; Shirokovsky, I. V.; Shumeiko, M. V.; Stoyer, M. A.; Stoyer, Ν. J.; Subbotin, V. G.; Sukhov, A. M.; Tsyganov, Yu. S.; Utyonkov, V. K.; Voinov, A. A.; Vostokin, G. K.

doi:10.1103/physrevc.87.054621

Cited by 131 publications

(55 citation statements)

References 39 publications

(36 reference statements)

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“…Or indirectly in the decay of heavier transactinides Uup and Uus produced in the fusion of 48 Ca with 243 Am [133][134][135][136], and 249 Bk [137,138]. The production path via the 243 Am( 48 Ca,xn) 291−x Uut reaction was recently confirmed at GSI Darmstadt [139].…”

Section: Productionmentioning

confidence: 81%

Chemical studies of elements with Z⩾ 104 in gas phase

2015

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Section: Productionmentioning

confidence: 81%

Chemical studies of elements with Z⩾ 104 in gas phase

2015

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“…Target materials ranging from 238 U to 249 Cf were irradiated with a 48 Ca beam. Despite the fact that the excitation energy is found to be substantially higher * umar@compsci.cas.vanderbilt.edu † volker.e.oberacker@vanderbilt.edu ‡ cedric.simenel@anu.edu.au in these experiments ('hot-fusion') researchers at JINR were able to create isotopes of elements Z = 113 − 118 [12][13][14][15][16], with lifetimes of milliseconds up to a minute. Recently, hotfusion experiments were also carried out at GSI, LBNL, and RIKEN [10,[17][18][19][20][21][22] which confirmed the discovery of elements Z = 112 − 117.…”

Section: Introductionmentioning

confidence: 94%

Fusion and quasifission dynamics in the reactionsCa48+Bk249and
Umar
¹
,
Oberacker
²
,
Simenel
³

2016
Phys. Rev. C
93
4
92
0
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Background: Synthesis of superheavy elements (SHE) with fusion-evaporation reactions is strongly hindered by the quasifission (QF) mechanism which prevents the formation of an equilibrated compound nucleus and which depends on the structure of the reactants. New SHE have been recently produced with doubly-magic 48 Ca beams. However, SHE synthesis experiments with single-magic 50 Ti beams have so far been unsuccessful.Purpose: In connection with experimental searches for Z = 117, 119 superheavy elements, we perform a theoretical study of fusion and quasifission mechanisms in 48 Ca, 50 Ti + 249 Bk reactions in order to investigate possible differences in reaction mechanisms induced by these two projectiles.Methods: The collision dynamics and the outcome of the reactions are studied using unrestricted time-dependent Hartree-Fock (TDHF) calculations as well as the density-constrained TDHF method to extract the nucleus-nucleus potentials and the excitation energy in each fragment.Results: Nucleus-nucleus potentials, nuclear contact times, masses and charges of the fragments, as well as their kinetic and excitation energies strongly depend on the orientation of the prolate 249 Bk nucleus. Long contact times associated with fusion are observed in collisions of both projectiles with the side of the 249 Bk nucleus, but not on collisions with its tip. The energy and impact parameter dependencies of the fragment properties, as well as their mass-angle and mass-total kinetic energy correlations are investigated.Conclusions: Entrance channel reaction dynamics are similar with both 48 Ca and 50 Ti projectiles. Both are expected to lead to the formation of a compound nucleus by fusion if they have enough energy to get in contact with the side of the 249 Bk target.

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“…In this work we study the 48 Ca+ 249 Bk reaction with the TDHF approach. The choice of this reaction is motivated by its success in forming the element Z = 117 [68][69][70][71][72]. Previous TDHF studies of quasifission with actinide targets were restricted to one or two orientations of the target to limit computational time.…”

Section: Introductionmentioning

confidence: 99%

Deformed shell effects in Ca48+Bk249 quasifission fragments

2019

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Background: Quasifission is the main reaction channel hindering the formation of superheavy nuclei (SHN). Its understanding will help to optimize entrance channels for SHN studies. Quasifission also provides a probe to understand the influence of shell effects in the formation of the fragments. Purpose: Investigate the role of shell effects in quasifission and their interplay with the orientation of the deformed target in the entrance channel. Methods: 48 Ca+ 249 Bk collisions are studied with the time-dependent Hartree-Fock approach for a range of angular momenta and orientations. Results: Unlike similar reactions with a 238 U target, no significant shell effects which could be attributed to 208 Pb "doubly-magic" nucleus are found. However, the octupole deformed shell gap at N = 56 seems to strongly influence quasifission in the most central collisions.Conclusions: Shell effects similar to those observed in fission affect the formation of quasifission fragments. Mass-angle correlations could be used to experimentally isolate the fragments influenced by N = 56 octupole shell gaps.On the theory side, quasifission has been studied with various approaches. This includes classical methods such as a transport model [34], the dinuclear system model [35][36][37][38], and models based on the Langevin equation [39][40][41][42][43]. Microscopic approaches such as quantum molecular dynamics [44][45][46] and the time-dependent Hartree-Fock (TDHF) theory [17,18,32,43,[47][48][49][50][51][52][53][54][55][56][57] have also been used. See [58][59][60][61] for recent reviews on TDHF.An advantage of microscopic calculations is that their only inputs are the parameters of the energy density functional describing the interaction between the nucleons. Since these parameters are usually fitted on nuclear structure properties only, such calculations do not require additional parameters determined from reaction mechanisms, such as nucleus-nucleus potentials. In addition, TDHF calculations treat both reaction mechanisms and structure properties on the same footing. This is important for reactions with actinide targets which exhibit a strong quadrupole deformation.

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Experimental studies of the249Bk + 48Ca reaction including decay properties and excitation function for isotopes of element 117, and discovery of the new isotope

Cited by 131 publications

References 39 publications

Chemical studies of elements with Z⩾ 104 in gas phase

Chemical studies of elements with Z⩾ 104 in gas phase

Fusion and quasifission dynamics in the reactionsCa48+Bk249and
Umar
¹
,
Oberacker
²
,
Simenel
³

2016
Phys. Rev. C
93
4
92
0
View full text Add to dashboard Cite

Deformed shell effects in Ca48+Bk249 quasifission fragments

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Experimental studies of the249Bk + 48Ca reaction including decay properties and excitation function for isotopes of element 117, and discovery of the new isotope

Cited by 131 publications

References 39 publications

Chemical studies of elements with Z⩾ 104 in gas phase

Chemical studies of elements with Z⩾ 104 in gas phase

Fusion and quasifission dynamics in the reactionsCa48+Bk249andUmar1, Oberacker2, Simenel3 2016Phys. Rev. C934920View full textAdd to dashboardCite

Deformed shell effects in Ca48+Bk249 quasifission fragments

Contact Info

Product

Resources

About

Fusion and quasifission dynamics in the reactionsCa48+Bk249and
Umar
¹
,
Oberacker
²
,
Simenel
³

2016
Phys. Rev. C
93
4
92
0
View full text Add to dashboard Cite