E1: Search for Superheaby Elements (SHE)
Search for SHE has been one of challenging subjects in
nuclear physics and has been studied at lots of laboratories
in the world such as DUBNA (Russia), LBL (USA), GSI (Germany),
etc. The element found at GSI with atomic number 111 is the
heaviest one at preset. The (HI, alpha+xn) reaction is found
to be very effective for production of SHE;, since it is shown
to occur even nuclear the Coulomb barrier in 40Ar induced reaction
on 209Bi and alpha emission can efficiently cool down a highly
excited nucleus both in energy and angular momentum. Based on
the idea, the measurement of the cross section of the 209Bi
(40Ar, alpha+xn)245-xEs reactions has been done using the
gas-filled recoil isotope separator (GARIS) developed in the
cyclotron Laboratory. The results provide very promising
evidence for the production of SHE. Further experiments searching
for heavier elements are now in progress.
Photograph of Gass-filled recoil separator (GARIS) and ion-
guide isotope separator (IGISOL)
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