新119番元素合成実験の現状

The 7th period of periodic table was completed with newly named four elements from nihonium (Z=113 [1]) to oganesson (Z=118). In superheavy nuclei/atoms with huge atomic and mass numbers, physical and chemical properties are modified by the strong Coulomb field. Discovery and production of those superheavy elements are essentially important in extending the field of such research and in searching for the limit of existence of heavy atom and nucleus.

Recently, search for element 119 has been started by the international collaboration consisting of RIKEN, ORNL, Kyushu Univ., etc. For the synthesis of new element with the highest atomic number, the recoil separator GARIS was redesigned and newly constructed. The upgrade of the linear accelerator is going on. A radioactive Cm target was developed in collaboration with ORNL. The talk will cover the current status of the search for new element 119 and the recent activities of the Research Center for SuperHeavy Elements newly founded in Kyushu University.

[1] K. Morita et al., Journal of the Physical Society of Japan 73, pp. 2593-2596 (2004).