Recent developments of SOLEROO: Australia’s first high energy radioactive Ion Beam capability

Abstract

Abstract. The first measurements of the Australian National University's new radioactive ion beam capability were carried out using elastic scattering of a 8 Li radioactive beam from a 197 Au target. The purpose of this experiment was to test the radioactive ion beam capability as a complete system, which uses a pair of twin position-sensitive parallel plate avalanche counters as tracking detectors along with a highly pixelated double sided Si detector array. The tracking detector system allows us to have extremely high purity secondary radioactive ion beams by electronically tagging the reaction products of interest, thus allowing complete separation from the unwanted contaminant beam species of similar mass and charge. Here, some recent developments and characteristics of this system are presented.

Elastic Scattering and Reaction Cross-section of 8Li on 209Bi

“…The lithium isotopes are particularly interesting as they exhibit a range of structural properties that may influence nuclear reaction mechanisms. The relatively well-bound 6,7 Li show cluster structures, which means they can be easily broken into an α and a 2,3 H respectively. Reaction cross-sections obtained for 6,7 Li + 208 Pb from precise elastic scattering data measured by Keeley et al [1] at energies above the barrier were found to be similar, with a slightly larger reaction cross-section for 6 Li attributed to a smaller breakup threshold (1.473 MeV) compared to that of 7 Li (2.467 MeV).…”

“…The relatively well-bound 6,7 Li show cluster structures, which means they can be easily broken into an α and a 2,3 H respectively. Reaction cross-sections obtained for 6,7 Li + 208 Pb from precise elastic scattering data measured by Keeley et al [1] at energies above the barrier were found to be similar, with a slightly larger reaction cross-section for 6 Li attributed to a smaller breakup threshold (1.473 MeV) compared to that of 7 Li (2.467 MeV). On the other end of this isotopic chain, is the exotic nucleus 11 Li, which has two loosely bound neutrons (S 2n = 0.369 MeV) around a relatively well-bound 9 Li core.…”

“…This results in a long tail in its density distribution and gives rise to very large reaction cross-sections at energies below and above its expected barrier [2,3]. 8 Li is intermediate between 7 Li and 11 Li and can be thought to consist of a cluster structure core of 7 Li and a loosely bound neutron (S n = 2.03 MeV). To understand the * e-mail: Chandrima.Sengupta@anu.edu.au , 0 (2020) Web of Conferences https://doi.org/10.1051/epjconf /2020 EPJ 227 227020 10 th European Summer School on Experimental Nuclear Astrophysics 2010 10 effect of this intermediate structure of 8 Li on reaction cross-sections, precise elastic scattering measurements are necessary.…”

“…Combining these data allows us to perform a thorough optical model analysis to obtain reaction cross-sections and provide a consistent description of elastic scattering. The systematics of reaction crosssections for 8 Li will then be compared with 6,7,9,11 Li data from the literature. The reaction cross-sections obtained for 8 Li will as well as be compared with the results obtained from high energy cross-section measurements, where similar root mean square (rms) nuclear radii were found for 6,7,8,9 Li [5].…”

“…In this work, elastic scattering was measured for 8 Li + 209 Bi at energies 2% to 34% above the barrier, allowing extraction of reaction crosssections. The systematics of the reaction cross-sections of 8 Li compared to neighbouring nuclei 6,7,9,11 Li are discussed.…”