"TASCA experiments with the reaction Pu-244 + Ca-48 leading to element 114: high cross sections and the new nucleus Hs-277"
Christoph E Düllmann, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
(id #95)
Seminar: YesPoster: No
Invited talk: No
In the past few years, the new gas-filled TransActinide Separator and Chemistry Apparatus TASCA was installed and commissioned at the GSI Helmholtz Center for Heavy Ion Research in Darmstadt. As a first highlight experiment in the region of the superheavy elements, the reaction Pu-244+Ca-48 leading to element 114 was studied.
In a one month long experiment, performed in the summer of 2009 at TASCA, thirteen atoms of the two most neutron-rich known isotopes of the superheavy element 114 with mass numbers 288 and 289 were observed. The high statistics allowed a reliable measurement of the cross section. The measured value of about 10 picobarn represents the largest cross section measured for any reaction leading to the presumably spherical superheavy elements. This opens up fascinating possibilities for more detailed studies of, e.g., the chemical behavior or atomic and nuclear structure of this superheavy element. Overall, the measured data, including the half-lives, which are of the order of one second, are in agreement with those reported from the DGFRS collaboration.
In one decay chain, the new isotope Hs-277 was observed. It decayed by spontaneous fission after a lifetime of 4.5 ms. With its neutron number N = 169 it is situated in the region of minimum stability, in between the last experimentally established deformed neutron shell at neutron number N=162 and the predicted spherical shell closure at N=184. The measured decay properties confirm the trends predicted by theoretical calculations.
In a one month long experiment, performed in the summer of 2009 at TASCA, thirteen atoms of the two most neutron-rich known isotopes of the superheavy element 114 with mass numbers 288 and 289 were observed. The high statistics allowed a reliable measurement of the cross section. The measured value of about 10 picobarn represents the largest cross section measured for any reaction leading to the presumably spherical superheavy elements. This opens up fascinating possibilities for more detailed studies of, e.g., the chemical behavior or atomic and nuclear structure of this superheavy element. Overall, the measured data, including the half-lives, which are of the order of one second, are in agreement with those reported from the DGFRS collaboration.
In one decay chain, the new isotope Hs-277 was observed. It decayed by spontaneous fission after a lifetime of 4.5 ms. With its neutron number N = 169 it is situated in the region of minimum stability, in between the last experimentally established deformed neutron shell at neutron number N=162 and the predicted spherical shell closure at N=184. The measured decay properties confirm the trends predicted by theoretical calculations.
