Mass, total kinetic energy, and neutron multiplicity correlations in the binary fragmentation of Ti50+Pb208 at 294 MeV bombarding energy

Abstract

The correlations between mass distributions of the binary fragments, total kinetic energy (TKE), and neutron multiplicity have been investigated for the reaction $^{50}\text{Ti}+\phantom{\rule{0.16em}{0ex}}^{208}\text{Pb}$ at 294 MeV bombarding energy. Although this reaction has been used to synthesize the Rf ($Z=104$) superheavy element, a complete study of its fragmentation dynamics is still not available in the literature. In this work, average neutron multiplicities were extracted as a function of different fragment mass splits and TKE windows. A weak increase of the prescission neutron multiplicity is observed going from asymmetric to symmetric mass splits. A fission delay time of $4.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}20}$ s has been extracted for the symmetric fission. The neutron multiplicity extracted for the symmetric mass split was used to derive the average number of neutrons emitted in the spontaneous fission of $^{258}\text{Rf}$. The extrapolated value of $4.7\ifmmode\pm\else\textpm\fi{}1.4$ is found to be consistent with systematics of spontaneous and neutron-induced fission in heavy nuclei and with the results of previous works for superheavy nuclei with $Z=116$ and $Z=124$.