Startup of superheavy element chemistry at RIKEN

Haba, Hiromitsu*; Akiyama, Takahiro*; Kaji, Daiya*; Kikunaga, Hidetoshi*; Kuribayashi, Takahiro*; Morimoto, Koji*; Morita, Kosuke*; Oe, Kazuhiro*; Sato, Nozomi*; Shinohara, Atsushi*; Takabe, Tomomasa*; Tashiro, Yuki*; Toyoshima, Atsushi; Yoneda, Akira*; Yoshimura, Takashi*

A review is given on the startup of the superheavy element (SHE) chemistry at RIKEN. A gas-jet transport system for the SHE chemistry has been coupled to the gas-filled recoil ion separator GARIS at the RIKEN Linear Accelerator. The performance of the system was appraised using Fr and Fm produced in the Tm(Ar,3)Fr and Pb(Ar,3)Fm reactions, respectively. The particles of Fr and Fm separated with GARIS and transported by the gas-jet were identified with a rotating wheel system for spectrometry under desired low background condition. The high gas-jet efficiencies over 80% were independent of the beam intensities up to 2 particle A. A gas-jet coupled target system for the production of SHEs was also installed on the beam line of the RIKEN K70 AVF cyclotron. The gas-jet transport of No and Rf produced in the U(Ne,5)No and Cm(O,5)Rf reactions, respectively, was conducted for the future chemical studies of Sg via the Cm(Ne, 5)Sg reaction.