Search for Superheavy Nuclei

Abstract

We describe the discoveries of new superheavy nuclei (a) with Z = 107-112 produced in cold fusion reactions between 208 Pb and 209 Bi and beams of A > 50 and (b) with Z = 113-118 in hot fusion reactions between actinide nuclei and 48 Ca. We also discuss the facilities used in these measurements. We compare the behavior of the α-decay energies and half-lives, spontaneous fission half-lives, cross sections, and excitation functions with expectations from theoretical calculations. Finally, we outline future research directions, including studies of the detailed properties of nuclei synthesized at higher yields, searches for new elements with Z = 119 and 120, and developments of new facilities.

Discovery of the elements with atomic numbers Z = 113, 115 and 117 (IUPAC Technical Report)

“…For seven of those, alpha decay to 262 Db had an average 8.67 MeV energy and for four cases the chains continued to the 4.1 s alpha decay of 258 Lr [15] with an average energy of 8.67 MeV all with excellent internal agreement and with the 2006 study of Qin et al [12]. These agree with the [6].) The colors indicate different decay modes for nuclide Z/A along with its half-life in milliseconds (ms), seconds (s), minutes (m) or hours (h) following the convention and data in [6] 113.…”

“…These agree with the [6].) The colors indicate different decay modes for nuclide Z/A along with its half-life in milliseconds (ms), seconds (s), minutes (m) or hours (h) following the convention and data in [6] 113. The properties of all three chains are reproduced in Fig.…”

“…Below, in Figure 1, is a convenient map of the super heavy nuclide region from the literature [6]. The dashed N,Z grid coordinate at 184,114 indicates the composition of the hypothesized doubly-magic nuclide 298 Fl.…”

Discovery of the element with atomic number Z = 118 completing the 7th row of the periodic table (IUPAC Technical Report)

“…A 2004 collaboration of Oganessian et al [10] reported the observation of one complete alpha-decay chain assigned to the [7].) The colors indicate different decay modes for nuclide Z/A along with its half life in milliseconds (ms), seconds (s), minutes (m) or hours (h) following the convention and data of [7], q.v.…”

Alpha Decay Chains of Superheavy Nuclei 278-282Rg

“…The use of cold fusion reactions enabled the discovery of six new elements, from bohrium (Z=107) to nihonium (Z=113) [8] and the use of hot fusion reactions led to the discovery of elements up to oganesson (Z=118) [8].…”