SYNTHESIS OF HEAVIEST ELEMENTS (RESULTS AND PROSPECTS)

2007 ◽  
Vol 16 (04) ◽  
pp. 949-956 ◽  
Author(s):  
YURI OGANESSIAN
Keyword(s):  
Cosmic Rays ◽  
Spontaneous Fission ◽  
Radioactive Decay ◽  
Superheavy Element ◽  
Parent Nucleus ◽  
Superheavy Nuclei ◽  
Α Decay ◽  
Decay Properties ◽  
Neutron Rich Isotope ◽  
Heaviest Elements

The formation and decay properties of the heaviest nuclei with Z = 112 - 116 and 118 were studied in the reactions 238 U , 242,244 Pu , 243 Am , 245,248 Cm and 249 Cf +48 Ca . The new nuclides mainly undergo sequential α-decay, which ends with spontaneous fission. The total time of decays ranges from 0.5 ms to about 1 day, depending on the proton and neutron numbers in the synthesized nuclei. The atomic number of the new elements 115 and 113 was confirmed also by an independent radiochemical experiment based on the identification of the neutron-rich isotope 268 Db (TSF ≈ 30 h ), the final product in the chain of α-decays of the odd–odd parent nucleus 288115. The comparison of the decay properties of 29 new nuclides with Z = 104 - 118 and N = 162 - 177 gives evidence for the decisive influence of the structure of superheavy nuclei on their stability with respect to different modes of radioactive decay. The investigations connected with the search for superheavy elements in Nature (cosmic rays) and prospects of superheavy element research are also presented.

Synthesis and decay properties of superheavy elements

2006 ◽  
Vol 78 (5) ◽  
pp. 889-904 ◽  
Author(s):  
Yuri Oganessian
Keyword(s):  
Nuclear Reactions ◽  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Radioactive Decay ◽  
Parent Nucleus ◽  
Heavy Ion ◽  
Superheavy Elements ◽  
Neutron Excess ◽  
Decay Properties ◽  
Neutron Rich Isotope

A fundamental outcome of modern nuclear theory is the prediction of the "island of stability" in the region of hypothetical superheavy elements. A significant enhancement in nuclear stability at approaching the closed shells with Z = 114 (possibly 120 and 122) and N = 184 is expected for the nuclei with large neutron excess. For this reason, for the synthesis of nuclei with Z = 112-116 and 118, we chose the reactions 238U, 242,244Pu, 243Am, 245,248Cm, and 249Cf + 48Ca, which are characterized by fusion products with a maximal neutron excess. The formation and decay properties of the heaviest nuclei were registered with the use of a gas-filled recoil separator installed at a 48Ca-beam of the heavy-ion cyclotron. The new nuclides mainly undergo sequential α-decay, which ends with spontaneous fission (SF). The total time of decay ranges from 0.5 ms to ~1 d, depending on the proton and neutron numbers in the synthesized nuclei. The atomic number of the new elements 115 and 113 was confirmed also by an independent radiochemical experiment based on the identification of the neutron-rich isotope 268Db (TSF ~ 30 h), the final product in the chain of α-decays of the odd-odd parent nucleus 288115. The comparison of the decay properties of 29 new nuclides with Z = 104-118 and N = 162-177 gives evidence of the decisive influence of the structure of superheavy elements on their stability with respect to different modes of radioactive decay. The investigations connected with the search for superheavy elements in Nature are also presented.The experiments were carried out at the Flerov Laboratory of Nuclear Reactions (JINR, Dubna) in collaboration with the Analytical and Nuclear Chemistry Division of the Lawrence Livermore National Laboratory (USA).

DECAY PROPERTIES AND STABILITY OF HEAVIEST ELEMENTS

2012 ◽  
Vol 21 (02) ◽  
pp. 1250013 ◽  
Author(s):  
A. V. KARPOV ◽  
V. I. ZAGREBAEV ◽  
Y. MARTINEZ PALENZUELA ◽  
L. FELIPE RUIZ ◽  
WALTER GREINER
Keyword(s):  
Superheavy Nuclei ◽  
Fusion Reactions ◽  
Β Decay ◽  
Α Decay ◽  
Experimental Identification ◽  
Nuclear Ground State ◽  
Decay Properties ◽  
Experimental Facilities ◽  
Neutron Rich Isotopes ◽  
Heaviest Elements

Decay properties and stability of heaviest nuclei with Z≤132 are studied within the macro-microscopical approach for nuclear ground state masses and phenomenological relations for the half-lives with respect to α-decay, β-decay and spontaneous fission. We found that at existing experimental facilities the synthesis and detection of nuclei with Z>120 produced in fusion reactions may be difficult due to their short half-lives (shorter than 1 μs). The nearest (more neutron-rich) isotopes of superheavy elements with 111≤Z≤115 to those synthesized recently in Dubna in 48 Ca -induced fusion reactions are found to be β+-decaying. This fact may significantly complicate their experimental identification. However it gives a chance to synthesize in fusion reactions the most stable superheavy nuclei located at the center of the island of stability. Our calculations yield that the β-stable isotopes 291 Cn and 293 Cn with a half-life of about 100 years are the longest-living superheavy nuclei located at the island of stability.

scholarly journals COHERENT DESCRIPTION FOR HITHERTO UNEXPLAINED RADIOACTIVITIES BY SUPER- AND HYPERDEFORMED ISOMERIC STATES

2003 ◽  
Vol 12 (05) ◽  
pp. 661-668 ◽  
Author(s):  
A. MARINOV ◽  
S. GELBERG ◽  
D. KOLB ◽  
R. BRANDT ◽  
A. PAPE
Keyword(s):  
High Spin ◽  
Radioactive Decay ◽  
Superheavy Element ◽  
Low Energy ◽  
Decay Properties ◽  
Particle Group ◽  
Isomeric States

Recently, long-lived high spin super- and hyperdeformed isomeric states with unusual radioactive decay properties have been discovered. Based on these newly observed modes of radioactive decay, consistent interpretations are suggested for previously unexplained phenomena seen in nature. These are the Po halos, the low-energy enhanced 4.5 MeV α-particle group proposed to be due to an isotope of a superheavy element with Z=108, and the giant halos.

Competition between decay modes of superheavy nuclei 281−310Og

2020 ◽  
Vol 29 (10) ◽  
pp. 2050087
Author(s):  
N. Sowmya ◽  
H. C. Manjunatha ◽  
P. S. Damodara Gupta
Keyword(s):  
Spontaneous Fission ◽  
Potential Model ◽  
Superheavy Element ◽  
Alpha Decay ◽  
Cluster Decay ◽  
Superheavy Nuclei ◽  
Temperature Dependent ◽  
Proximity Potential ◽  
Decay Modes

In this work, we have made an attempt to study the cluster-decay half-lives and alpha-decay half-lives of the superheavy nuclei [Formula: see text]Og by considering the temperature-dependent (TD) and also temperature-independent (TID) proximity potential model. The evaluated half-lives were compared with that of the experiments. To predict the decay modes, we have compared the cluster-decay half-lives and alpha-decay half-lives with that of spontaneous fission half-lives. This work also predicts the decay chains of the superheavy nuclei [Formula: see text]Og and finds an importance in the synthesis of further isotopes of superheavy element Oganesson.

Stability of superheavy nuclei against α-decay and spontaneous fission

2013 ◽  
Vol 898 ◽  
pp. 24-31 ◽  
Author(s):  
Chang Xu ◽  
Xin Zhang ◽  
Zhongzhou Ren
Keyword(s):  
Spontaneous Fission ◽  
Superheavy Nuclei ◽  
Α Decay

PROPERTIES OF SUPERHEAVY NUCLEI IN VARIOUS MACROSCOPIC-MICROSCOPIC MODELS

2005 ◽  
Vol 14 (03) ◽  
pp. 365-372 ◽  
Author(s):  
A. BARAN ◽  
M. KOWAL ◽  
Z. ŁOJEWSKI ◽  
K. SIEJA
Keyword(s):  
Spontaneous Fission ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Electric Quadrupole ◽  
Superheavy Nuclei ◽  
Quadrupole Moments ◽  
Α Decay ◽  
Macroscopic Models ◽  
Microscopic Models ◽  
Three Dimensional Space

In the framework of various macroscopic-microscopic models we examine the ground state properties: separation energies, mean square charge radii, electric quadrupole moments as well as fission barriers, mass parameters, spontaneous fission and α decay half-lives of superheavy nuclei. Four macroscopic models and two models of pairing interactions are applied and studied. The approach is based on the deformed Woods-Saxon potential. Spontaneous fission half-lives are calculated within a multi-dimensional dynamical-programming method where the action integral is minimized within the three dimensional space of the nuclear deformation parameters {β2, β4, β6}.

Theoretical prediction of probable isotopes of superheavy nuclei of Z = 122

2016 ◽  
Vol 25 (11) ◽  
pp. 1650100 ◽  
Author(s):  
H. C. Manjunatha
Keyword(s):  
Theoretical Prediction ◽  
Spontaneous Fission ◽  
Decay Channel ◽  
Superheavy Element ◽  
Alpha Decay ◽  
Superheavy Nuclei ◽  
Semiempirical Relation ◽  
Analytical Formulas ◽  
C 78 ◽  
Good Agreement

We have studied the [Formula: see text]-decay half-life and spontaneous fission half-lives of isotopes of superheavy element [Formula: see text] in the range [Formula: see text]. A comparison of calculated alpha half-lives with the literature [D. N. Poenaru, R. A. Gherghescu and W. Greiner, Phys. Rev. C 83 (2011) 014601, D. N. Poenaru, R. A. Gherghescu and W. Greiner, Phys. Rev. C 85 (2012) 034615] and the analytical formulas of Royer [G. Royer, J. Phys. G; Nucl. Part. Phys. 26 (2000) 1149] shows good agreement with each other. To identify the mode of decay of these isotopes, the spontaneous-fission half-lives were also evaluated using the semiempirical relation given by [C. Xu, Z. Ren and Y. Guo, Phys. Rev. C 78 (2008) 044329]. A comparative study on the competition of alpha decay versus spontaneous fission of superheavy nuclei (SHN) reveals that around eight isotopes ([Formula: see text]122) survive fission and have alpha decay channel as the prominent mode of decay and hold the possibility to be synthesized in the laboratory. The alpha decay half-lives and spontaneous fission half-lives of SHN with [Formula: see text], [Formula: see text]–306, with [Formula: see text], [Formula: see text]–300, and with [Formula: see text], [Formula: see text]–297 are also studied. The present study will be useful in the synthesis of superheavy elements [Formula: see text] by using the actinide based reactions with stable projectiles heavier than [Formula: see text]Ca.

Comparison of alpha decay with fission for isotopes of superheavy nuclei Z = 124

2016 ◽  
Vol 25 (09) ◽  
pp. 1650074 ◽  
Author(s):  
H. C. Manjunatha
Keyword(s):  
Superheavy Element ◽  
Alpha Decay ◽  
Superheavy Nuclei ◽  
Universal Curve ◽  
Proximity Potential ◽  
Deformed Nuclei ◽  
Decay Properties ◽  
Semiempirical Relation ◽  
Analytical Formulas ◽  
C 78

We have studied the [Formula: see text]-decay properties of superheavy nuclei (SHN) [Formula: see text] in the range [Formula: see text] using the Coulomb and proximity potential model for deformed nuclei (CPPMDN). The calculated [Formula: see text] half-lives agree with the values computed using the Viola–Seaborg systematic, the universal curve of Poenaru et al. [Phys. Rev. C 83 (2011) 014601; 85 (2012) 034615] and the analytical formulas of Royer [J. Phys. G[Formula: see text] Nucl. Part. Phys. 26 (2000) 1149]. To identify the mode of decay of these isotopes, the spontaneous-fission half-lives were also evaluated using the semiempirical relation given by Xu et al. [Phys. Rev. C 78 (2008) 044329]. The calculated half-lives help to predict the possible isotopes of this superheavy element [Formula: see text]. As we could observe [Formula: see text] chain consistently from the nuclei [Formula: see text]124, we have predicted that these nuclei could not be synthesized and detected experimentally via [Formula: see text] decay as their decay half-lives are too small. The nuclei [Formula: see text]124 were found to have long half-lives and hence could be sufficient to detect them if synthesized in a laboratory.

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