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[en] In the present study, it is proposed N/Z dependence of Ebal as a probe of symmetry energy and its density dependence. The present study is carried within the framework of isospin-dependent quantum molecular dynamics (IQMD) model
[en] Proton number, Z, and mass number,A, assignments for newly discovered heavy element nuclides have historically been made by observing α decay to a daughter with well-established Z and A, and then observing the well-know decay of that daughter. For all of the new superheavy element isotopes observed in "4"8Ca irradiations of actinide targets, this correlation technique has not been possible, because the α-decay chains end in spontaneous fission of previously unknown isotopes. Consequently, Z and A assignments have been made by less-direct means. The superheavy element Z and A assignment methods are summarized, and possibilities for how they may be incorrect are explored. While it is highly likely that most of the superheavy element Z and A assignments are correct, there is a real need for a direct proof.
[en] It is shown that by applying PCAC, the 2β-decay process can be directly related to the pion induced double charge exchange (DCX) nuclear reaction. Thus, if the experimental data of forward-angle cross section on Ca40 with pion beam at 164 MeV is used and extrapolated to Ca48, then the calculated life time of Ca48 will be much larger than the old theoretical estimations by a factor 105∼106
[en] The collision of heavy-ions at low incident energies and subsequently, their fusion has always attracted nuclear researchers. This is primarily due to the fact that fusion dynamics gives possibility to study the nuclear interactions as well as structural aspects of heavy-ions. The comparison of three attempts of proximity potentials for fusion of large number of colliding nuclei have been presented
[en] Independent verification of the production of element 114 in the reaction of 244-MeV 48Ca with 242Pu is presented. Two chains of time- and position-correlated decays have been assigned to 286114 and 287114. The observed decay modes, half-lives, and decay energies agree with published results. The measured cross sections at a center-of-target energy of 244 MeV for the 242Pu(48Ca,3-4n)287,286114 reactions were 1.4-1.2+3.2 pb each, which are lower than the reported values.
[en] A 2 years long cooperation between Russian and American scientists have led to the discovery of the element Z = 117. The physicists from Dubna (Russia) have made a beam of Ca48 impinged on a berkelium target for 150 days. The berkelium target was produced as the result of a 250 days long irradiation of an americium-curium target by intense neutron flux at Oak-ridge laboratories (Usa). The separation and purification steps of the amount (22*10-3 g) of produced berkelium have lasted 90 days. Eventually only 6 nuclei of the 117-element have been produced. The value of the decay constant confirms that we are in a rather stable zone. A further investigation of this zone requires the production of nuclei with more neutrons which is difficult to do with today's tools. In 2013 a new installation at GANIL: Spiral-2 will provide 1000 times more as intense nuclei beams as today and will turn GANIL into a valuable place for the production of new heavy elements. (A.C.)
[en] The observation of atomic numbers Z by 40% larger than that of Bi, the heaviest stable element, is an impressive extension in nuclear survival. Although the super heavy nuclei (SHN) are at the limits of Coulomb stability, shell stabilization lowers the ground-state energy, creates a fission barrier, and thereby enables the SHN to exist. The fundamentals of the modern theory concerning the mass limits of nuclear matter have thus obtained experimental verification.
[en] The first and second attempt to identify chemically one of the recently discovered long-lived isotopes of superheavy elements, namely 283112 (3 min, SF), made at FLNR, Dubna is reported. The nuclide was produced by fusion of accelerated 48Ca with a target of natural U which contained some Nd to simultaneously produce also short-lived Hg nuclides. According to test experiments with Hg, the expected lighter homologue of element 112, both elements can be isolated from the products of the bombardment in metallic state, and transported from the target in flowing He gas to a detection system. Spontaneous fission and alpha decays (49-s 185Hg) were registered in the first experiment using PIPS detectors. The surface of the detectors was covered with a thin layer of Au or Pd, which ensured the detection of Hg with high efficiency due to its chemisorption on these surfaces. While about three SF events could be expected, not a single one was detected at an upper limit for the production cross section of about one picobarn. This may point to a 'Rn-like' rather than 'Hg-like' behavior of element 112. A new experiment is planned to be in November 2001, in which both a 'Rn-like' and a 'Hg-like' species could be detected with PIPS detectors and special flow-through ionization chamber. (author)
[en] In the present work, the simulation of heavy ion collision for mass asymmetric reaction: 40Ca + 48Ca and mass symmetric reaction: 48Ca + 48Ca is carried out at and around barrier energies using CMD-Model and the fusion cross-sections are calculated using barrier parameters which are obtained from the dynamically evolved ion-ion potential using Wong's Formula