Resonant scattering studies of 24Mg and 28Mg and the search for nuclear water

Walshe, Joseph Michael (2016). Resonant scattering studies of 24Mg and 28Mg and the search for nuclear water. University of Birmingham. Ph.D.

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Abstract

The neutron-rich nucleus 28Mg has been studied for the first time above the particle decay threshold using α-particle resonant scattering with a beam of radioactive 24Ne ions from the SPIRAL facility at GANIL. The thick target inverse kinematics technique was used to permit measurement of the differential cross section at 180◦ in the centre-of-mass frame, for the excitation energy region from 15 to 21 MeV, with a single beam energy. Since no previous experimental data exist with which to compare the current work, data were also taken for 24Mg using a 20Ne beam with the same experimental set-up. Comparison of these data with previous work yields excellent agreement and so validates the data collection method. In 28Mg, energies and widths of thirteen new states are reported with relative strengths given for ten of these. For two states, spin-parity assignments are made and it is found, by calculation of the α-decay branching ratios and comparison to a theoretical model, that these two states do not appear to be strongly α clustered. The underlying structure of 28Mg in this region is therefore not clear, and further experimental work is required in order to establish a full understanding, with a particular focus on the energy resolution of the measurement. The experimental technique is a powerful tool for the study of α elastic scattering cross sections, and combined with new radioactive beam facilities will prove an effective method of investigating α clustering in a wide range of unstable nuclei.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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