Departmental Seminar

Characterization of the heavy-ion fusion reactions mechanism in Cr + W reactions

Ms K. Hammerton
Michigan State University
Thursday 28 April 2016 11am–12.30pm
Nuclear Physics Seminar Room 57 Garran Road

Heavy ion fusion reactions serve as the primary mechanism for the production of superheavy elements.  A crucial step in this reaction mechanism is the formation of a fully equilibrated compound nucleus.  Compound nucleus fusion can be hindered by orders of magnitude by quasifission, a process in which the dinuclear system breaks apart prior to full equilibration.   Characterization of the quasifission process is vital to providing a complete description of the heavy ion fusion reaction mechanism.  Mass and angle distributions of fragments formed via 8 Cr + W reactions were measured at the Australian National University to explore the interplay between the fusion-fission and quasifission reaction channels with varying neutron-richness.  The reactions were measured in two energy regimes: at 13% above the Bass fusion barrier and at 52.0 MeV of excitation energy in the compound nucleus, E*CN.  At Ec.m./ VBass = 1.13, there is a clear dependence on the neutron-richness.  For the reactions at E*CN = 52.0 MeV, the dependence is less clear and additional factors such as the energy available for rotation play a vital role.  This work demonstrates that quasifission is an important consideration in understanding the heavy-ion fusion reaction mechanism for intermediate mass projectiles.


Ms Petra Rickman

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