Oct 29 – 30, 2012
Europe/Zurich timezone

Isospin dependence in heavy-element synthesis in fusion-evaporation reactions with neutron-rich radioactive ion-beams

Oct 29, 2012, 12:00 PM
40/S2-D01 - Salle Dirac (CERN)

40/S2-D01 - Salle Dirac


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Dr Alexander Yakushev (GSI Helmholtzzentrum für Schwerionenforschung GmbH)


Climbing up the "Island of Stability" and approaching the long-predicted next spherical neutron shell closure at N=184 is a persistent dream hampered, among others, by the lack of (i) sufficiently neutron-rich target and projectile combinations and (ii) insufficient knowledge about the projectile isospin (T=(N-Z)/2) dependence of the fusion neutron-evaporation residue cross section. With the advent of radioactive ion-beam facilities, which are delivering ever more intense neutron-rich ion beams, the answer to the latter question is now coming within reach. "Hot-fusion" reactions based on relatively light (A ~ 20 - 50) neutron-rich projectiles and heavy actinide targets have been exploited to access relatively neutron-rich isotopes of the heaviest elements. See, e.g. [1] for an overview of reactions with 48Ca leading to the most neutron-rich known isotopes, which belong to elements Z=112-118. Still, in these elements, the neutron number N=184 cannot be reached using complete fusion-evaporation reactions with stable isotope beams, and when going to yet heavier elements with Z~122-124, cross sections are predicted to be orders of magnitude smaller than those nowadays accessible in even the most advanced and sensitive experiments. Therefore, to reach N=184, more neutron-rich radioactive beams of high intensity are required [2]. Systematic studies to investigate the role of isospin on the magnitude of fusion-evaporation reacations that include exotic neutron-rich radioactive beams are still scarce (see, e.g., [3]). We suggest pursuing the "hot-fusion" path in our investigations on the projectile isospin dependence of heavy element fusion-evaporation residue cross sections at Coulomb barrier energies by exploiting the Ar + Sm  Hg system [4] and using intense beams of exotic Ar isotopes available at the TSR [5]. Neutron-evaporation residues will be detected in an ultrasensitive nuclear chemical detection system [6], which is also applied for nuclear chemical studies of single atoms of superheavy elements [7]. References [1] Yu. Oganessian, J. Phys. G 34 (2007) R165 [2] W. Loveland et al., Phys. Rev. C 76 (2007) 014612 [3] J.F. Liang et al., Int. J. Mod. Phys. E 14 (2006) 1121 [4] M. Schädel et al., GSI Scientific Report 2003 (2004), p. 20 [5] M. Grieser et al., Eur. Phys. J. Special Topics 207 (2012) 1 [6] J. Dvorak et al., Phys. Rev. Lett. 97 (2006) 242501; 100 (2008) 132503 [7] A. Yakushev et al., to be submitted to Inorg. Chem.

Primary author

Dr Alexander Yakushev (GSI Helmholtzzentrum für Schwerionenforschung GmbH)


Prof. Christoph Emanuel Duellmann (GSI, Uni Mainz, Helmholtz Institute Mainz) Dr Jadambaa Khuyagbaatar (Helmholtz Institute Mainz, Germany) Dr T. Mendonca (CERN) Prof. Thierry Stora (CERN)

Presentation materials