Measurements of cross sections and decay properties of the isotopes of elements 112, 114, and 116 produced in the fusion reactionsU233,238,Pu242, andCm248+Ca48

Abstract

We have studied the dependence of the production cross sections of the isotopes ${}^{282,283}112$ and ${}^{286,287}114$ on the excitation energy of the compound nuclei ${}^{286}112$ and ${}^{290}114$. The maximum cross section values of the $xn$-evaporation channels for the reaction ${}^{238}\mathrm{U}({}^{48}\mathrm{Ca},xn){}^{286-x}112$ were measured to be ${\sigma }_{3n}={2.5}_{-1.1}^{+1.8}\mathrm{pb}$ and ${\sigma }_{4n}={0.6}_{-0.5}^{+1.6}\mathrm{pb}$; for the reaction ${}^{242}\mathrm{Pu}({}^{48}\mathrm{Ca},xn){}^{290-x}114$: ${\sigma }_{2n}\sim 0.5\mathrm{pb}$, ${\sigma }_{3n}={3.6}_{-1.7}^{+3.4}\mathrm{pb}$, and ${\sigma }_{4n}={4.5}_{-1.9}^{+3.6}\mathrm{pb}$. In the reaction ${}^{233}\mathrm{U}({}^{48}\mathrm{Ca},2–4n){}^{277–279}112$ at $E*=34.9\pm 2.2\mathrm{MeV}$ we measured an upper cross section limit of ${\sigma }_{xn}⩽0.6\mathrm{pb}$. The observed shift of the excitation energy associated with the maximum sum evaporation residue cross section ${\sigma }_{\mathrm{ER}}(E*)$ to values significantly higher than that associated with the calculated Coulomb barrier can be caused by the orientation of the deformed target nucleus in the entrance channel of the reaction. An increase of ${\sigma }_{\mathrm{ER}}$ in the reactions of actinide targets with ${}^{48}\mathrm{Ca}$ is consistent with the expected increase of the survivability of the excited compound nucleus upon closer approach to the closed neutron shell $N=184$. In the present work we detected 33 decay chains arising in the decay of the known nuclei ${}^{282}112$,

Keywords

• EXCITATION
• NEUTRONS
• CROSS SECTION
• ALPHA DECAY
• ION BEAM
• ELEMENT 116
• SPONTANEOUS FISSION
• ELEMENT 114

This publication has 46 references indexed in Scilit:

• Measurements of cross sections for the fusion-evaporation reactionsPu244(Ca48,xn)292−x114andCm245(Ca48,xn)293−x116
  Physical Review C, 2004
• Heavy element research at Dubna
  Nuclear Physics A, 2004
• Second experiment at VASSILISSA separator on the synthesis of the element 112
  The European Physical Journal A, 2004
• Synthesis of superheavy nuclei in the reactions of 244Pu and 248Cm with 48Ca
  The European Physical Journal A, 2002
• Synthesis of 292116 in the 248Cm + 48Ca reaction
  Physics of Atomic Nuclei, 2001
• Observation of the decay of292116
  Physical Review C, 2000
• Synthesis of superheavy nuclei in 48Ca+244Pu interactions
  Physics of Atomic Nuclei, 2000
• Synthesis of superheavy nuclei in the48Ca+244Pureaction:288114
  Physical Review C, 2000
• Synthesis of nuclei of the superheavy element 114 in reactions induced by 48Ca
  Nature, 1999
• Search for new isotopes of element 112 by irradiation of 238U with 48Ca
  The European Physical Journal A, 1999

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