125263866
Measurements of cross sections for the fusion-evaporation reactions pu-244(ca-48, xn) 114-(292-x) and cm-245(ca-48, xn) 116-(293-x)
We have studied the excitation functions of the reactions 244Pu(48Ca,xn). Maximum cross sections for the evaporation of 3–5 neutrons in the complete-fusion reaction 244Pu+48Ca were measured to be s3n=2 pb,s4n =5 pb, ands5n=1 pb. The decay properties of 3 n-evaporation product 289114, in the decay chains observed at low 48Ca energy coincide well with those previously observed in the 244Pu+48Ca and248Cm+48Ca reactions and assigned to288114. Two isotopes of element 114 and their descendant nuclei were identified for the first time at higher bombarding energies: 288114 (Ea=9.95 MeV, T1/2=0.6 s) and 287114 (Ea=10.04 MeV,T1/2 =1 s). We also report on the observation of new isotopes of element 116, 290,291116, produced in the245Cm +48Ca reaction with cross sections of about 1 pb. A discussion of self-consistent interpretations of all observed decay chains originating at Z=118, 116, and 114 is presented.
124000648
Synthesis of the isotope 282 113 in the Np237+Ca48 fusion reaction
The decay properties of the new isotope ${}^{282}113$ and its daughter nuclei have been measured in the $^{237}\mathrm{Np}$($^{48}\mathrm{Ca}$, $3n$)${}^{282}113$ reaction. During an irradiation with a beam dose of $1.1\ifmmode\times\else\texttimes\fi{}{10}^{19}244$-MeV $^{48}\mathrm{Ca}$ projectiles, two decay chains originating from the odd-odd isotope ${}^{282}113$ $({E}_{\ensuremath{\alpha}}=10.63\ifmmode\pm\else\textpm\fi{}0.08\phantom{\rule{0.3em}{0ex}}\mathrm{MeV},{T}_{\ensuremath{\alpha}}={73}_{\ensuremath{-}29}^{+134}\phantom{\rule{0.3em}{0ex}}\mathrm{ms})$ were produced in the complete fusion reaction with a cross section of $0.{9}_{\ensuremath{-}0.6}^{+1.6}$ pb; these properties are all in agreement with expectations based on the results of previous experiments.
45838927
Discovery of enhanced nuclear stability near the deformed shells N=162 and Z=108.
In bombardments of [sup 248]Cm with [sup 22]Ne we discovered two new isotopes, [sup 265]106 and [sup 266]106, by establishing genetic links between their [alpha] decays and spontaneous fission (SF) or [alpha] decays of the daughter nuclides. We measured [ital E][sub [alpha]]=8.63[plus minus]0.05 MeV for [sup 266]106 and a half-life of 1.2 s for its daughter [sup 262]104. For [sup 265]106 we measured [ital E][sub [alpha]]=8.71 to 8.91 MeV. From these [alpha] energies we estimated [alpha] half-lives of 10--30 s for [sup 266]106 and 2--30 s for [sup 265]106. We estimated SF branches of 50% or less for both isotopes. The decay properties of [sup 266]106 establish the existence of enhanced nuclear stability near the predicted deformed shells [ital N]=162 and [ital Z]=108.
124212969
Experiments on the synthesis of element 115 in the reaction am-243(ca-48, xn) x-115-291
98565967
Synthesis of the New Element with Z=117
The synthesis of the new chemical element with atomic number Z=117 is presented. The isotopes 293117 and 294117were produced in fusion reactions between 48Ca and 249Bk. The 249Bk was produced in the High Flux Isotope Reactor and chemically separated at Oak Ridge. Decay chains involving eleven new nuclei were identified by means of the Dubna Gas Filled Recoil Separator. The measured decay properties show a strong rise of stability for super-heavy nuclei toward N=184.
91274134
Experiments on synthesis of superheavy nuclei by reactions with Ge ions