Investigation of heavy ion reaction mechanisms by means of the inclusive 93Nb(12C,7Be) and 93Nb(12C,9Be) reactions

Becker, Bruce

Investigation of heavy ion reaction mechanisms by means of the inclusive 93Nb(12C,7Be) and 93Nb(12C,9Be) reactions

Master Thesis

2002

Publisher

University of Cape Town

Department

Department of Physics

Faculty

Faculty of Science

Abstract

Inclusive continuum cross-sections for the reactions 93Nb(12C,7Be) and 93Nb(12C,9Be) were measured at the NAC using a ΔE - E setup. A theoretical light output model which could account for the mass and charge dependance of the NaI E detectors was employed to calibrate the NaI(TI) detectors. The model is outlined and it is shown that the nonlinearity of the detector response is only due to a term which describes the mass-dependance. Investigation of the cross-sections revealed interesting facts about the dominant reaction mechanisms in the interaction of 120 with heavy targets. A theoretical model developed by the Milano group has been very successful in describing the continuum cross-sections of a particles (including 9Be) created in similar reactions of 120 and 160, incident on heavy targets. The analysis shows that the same description of the continuum cross-sections of 7Be and 9Be gives good agreement with the data (with different energy-loss parameters and survival probabilities), although there are discrepancies, especially at the lower incident angles. These small discrepancies may indicate the presence of a multistep direct reaction between the detected fragment and the residual nucleus in the exit channel. The most notable result of the analysis of the data was that the spectra of 7Be and 9Be, previously suspected to be created in a final-state interaction of sBe with the residual nucleus, are well-described by a friction-dissipative breakup mechanism.

Description

Includes bibliographical references.

Keywords

Physics

Reference:

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Masters

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