Mid Term Review

Elastic Scattering Measurement of 8Li on heavy and medium mass targets at the Australian National University

Miss Chandrima Sengupta
Department Nuclear Physics

Exotic nuclei such as 8Li and 6He have weakly bound neutrons around a relatively tightly bound core, which have a strange influence on nuclear reaction mechanism, especially at bombarding energies in the Coulomb barrier region. The nucleon distribution density of such nuclei has an extensive tail which allows the attractive nuclear force to act at large distances. This effectively lowers the fusion barrier, enhancing fusion cross-section, particularly, in the sub-barrier energy region. However, these nuclei are weakly bound, and the interaction with the target may cause them to break up. As a consequence, only part of the projectile may fuse with the target, therefore suppressing fusion cross-sections. The weak intensity of these radioactive beams sets a limit on the accuracy attainable in cross section measurements, and the results obtained regarding the interplay of weak binding, break up and fusion have so far not been conclusive.

A Radioactive Ion Beam (RIB) capability built around a solenoidal separator, has been developed at the Australian National University to study these exotic nuclei. Tracking detectors (PPACs) are used to tag the secondary beam and track it on to the secondary target. This tracking capability allows precise measurements of elastic scattering to be made, which gives insights in to the interaction potentials of the exotic isotopes, and extract reaction cross-sections. The elastic scattering of 8Li on heavy and medium mass targets has recently been performed using the capability available at ANU. The reaction products have been measured with a double sided silicon strip detector array (BALiN). To properly normalise the elastic scattering data, the divergence of the secondary beam and finite size of the beam spot on the secondary target have been taken in to account in a simulation of Rutherford Scattering. This talk describes the RIB capability available at ANU and all the possible factors that should be taken in to account to obtain a reliable elastic scattering angular distribution.

Date & time

Thu 26 Apr 2018 11am – Tue 17 Apr 2018 12pm





Members of RSPE welcome