New isotope <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Mc</mml:mi><mml:mprescripts/><mml:none/><mml:mn>286</mml:mn></mml:mmultiscripts></mml:math> produced in the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mmultiscripts><mml:mi>Am</mml:mi><mml:mprescripts/><mml:none/><mml:mn>243</mml:mn></mml:mmultiscripts><mml:mo>+</mml:mo><mml:mmultiscripts><mml:mi>Ca</mml:mi><mml:mprescripts/><mml:none/><mml:mn>48</mml:mn></mml:mmultiscripts></mml:mrow></mml:math> reaction
Yu. Ts. Oganessian, V. K. Utyonkov, N. D. Kovrizhnykh, F. Sh. Abdullin, S. N. Dmitriev, Alan A. Dzhioev, D. Ibadullayev, М. Г. Иткис, А. В. Карпов, D. A. Kuznetsov, O. V. Petrushkin, A. V. Podshibiakin, А. N. Polyakov, A. G. Popeko, I. S. Rogov, R. N. Sagaidak, L. Schlattauer, V. D. Shubin, M. V. Shumeiko, D. I. Solovyev, Yu. S. Tsyganov, A. A. Voinov, V. G. Subbotin, A. Yu. Bodrov, A. V. Sabelnikov, A. V. Khalkin, K. P. Rykaczewski, T. King, J. B. Roberto, N. T. Brewer, R. Grzywacz, Z. G. Gan, Z. Y. Zhang, M. H. Huang, H. B. Yang
Abstract
In this paper, we present results of the second experiment on the synthesis of Mc isotopes in the $^{243}\mathrm{Am}+^{48}\mathrm{Ca}$ reaction performed at the gas-filled separator DGFRS-2 of the SHE Factory at JINR. The new isotope $^{286}\mathrm{Mc}$ was synthesized, and its half-life of $20\begin{array}{c}+98\\ \ensuremath{-}9\end{array}$ ms and \ensuremath{\alpha}-particle energy of $10.71\ifmmode\pm\else\textpm\fi{}0.02$ MeV were determined. A $^{286}\mathrm{Mc} \ensuremath{\alpha}\text{\ensuremath{-}}\mathrm{decay}$ chain was recorded down to the spontaneous fission of $^{266}\mathrm{Db}$. The spontaneous fission of $^{279}\mathrm{Rg}$ was observed for the first time in one of four new decay chains of $^{287}\mathrm{Mc}$. The excitation function of the reaction was measured at three $^{48}\mathrm{Ca}$ energies of 242, 250, and 259 MeV; the latter resulted in the first observation of the $5n\text{\ensuremath{-}}\mathrm{evaporation}$ channel with a cross section of $0.{5}_{\ensuremath{-}0.4}^{+1.3}$ pb. The decay properties of 21 previously known $\mathrm{odd}\text{\ensuremath{-}}Z$ isotopes were improved. The potential for an electron-capture decay mode is discussed for $^{288}\mathrm{Mc}$ and $^{284}\mathrm{Nh}$ isotopes. The half-lives of spontaneously fissioning nuclei produced in the $^{48}\mathrm{Ca}\text{\ensuremath{-}}\mathrm{induced}$ reactions with actinide targets are compared with several theoretical predictions.