https://doi.org/10.1140/epjad/i2005-06-134-9
ENAM 2004
New elements from Dubna
1
Joint Institute for Nuclear Research, 141980, Dubna, Russian Federation
2
Lawrence Livermore National Laboratory, University of California, 94551, Livermore, CA, USA
* e-mail: utyonkov@sungns.jinr.ru
Received:
19
October
2004
Accepted:
19
March
2005
Published online:
29
June
2005
We have studied the dependence of the production cross-sections of the isotopes 282, 283112 and 286-288114 on the excitation energy of the compound nuclei 286112 and 290114. The maximum cross-sections of the xn-evaporation channels for the reaction 238 U(48 Ca, xn)286-x112 were measured to be: σ3n = 2.5+1.8 -1.1pb and σ4n = 0.6+1.6 -0.5pb; for the reaction 242 Pu(48 Ca, xn)290-x114: σ2n ∼ 0.5pb, σ3n = 3.6+3.4 -1.7pb and σ4n = 4.5+3.6 -1.9pb. In the reaction 233 U(48 Ca, 2-4n)277-279112 we measured an upper cross-section limit of σxn≤0.6pb. An increase of σER in the reactions of actinide targets with 48Ca can be due to the expected increase of the survivability of the excited compound nucleus upon closer approach to the closed neutron shell N = 184. The observed nuclear decay properties of the nuclides with Z = 104-118 are compared with theoretical nuclear mass calculations and the systematic trends of α-decay properties. As a whole, they give a consistent pattern of decay of the 18 even-Z neutron-rich nuclides with Z = 104-118 and N = 163-177.
PACS: 25.70.Gh Compound nucleus – / 23.60.+e α decay – / 25.85.Ca Spontaneous fission – / 27.90.+b 220 ⩽ A –
© Società Italiana di Fisica and Springer-Verlag, 2005