PhD Thesis Studentship in Nuclear Physics

Spectroscopy of light neutron-rich nuclei by single-neutron knockout reactions

Thesis Supervisor: Dr Marielle Chartier

Nuclear structure studies have acquired a new dimension as a result of the recent availability of intermediate-energy radioactive ion beams produced via projectile-fragmentation techniques at facilities like GANIL and GSI in Europe and the NSCL(MSU) in the USA. The route to achieving a better understanding of the effective nuclear interaction lies in testing the predictions and limits of applicability of nuclear models by probing the detailed structure of the so-called exotic nuclei, with very unbalanced neutron and proton numbers, produced at these facilities. The interest in studying light neutron-rich nuclei is driven in part by the predicted evolution of single-particle energies, such that traditional shell gaps may disappear and new magic numbers may arise far from stability. One particularly interesting puzzle in the region of light neutron-rich nuclei is the particle instability of oxygen isotopes starting from ²⁵O, whereas the fluorine isotopes, with just one more proton, are bound up to ³¹F. The reduction of the N=20 shell gap and the appearance of a new shell gap at N=16 have been invoked to explain this effect, as suggested by neutron separation-energy systematics. However a quantitative understanding is still missing, for which detailed spectroscopic information in this region is needed.

For the study of these loosely bound nuclear systems single-neutron removal – ‘knockout’ – reactions are a new very promising and powerful tool to obtain detailed spectroscopic information and understand the evolution of shell structure far from stability. A pioneering experiment has recently been approved at GANIL (Caen, France) in order to perform single-neutron knockout reactions using the high-resolution SPEG spectrometer and measuring coincident g-rays with the germanium (EXOGAM) and barium-fluoride (Chateau de Cristal) detector arrays. This will allow spectroscopic factors in the isotopic chains of oxygen, fluorine and neon isotopes to be extracted and will shed light on the possible new N = 16 shell closure.

A three-year postgraduate studentship, including £31,500 for subsistence and £8,610 for the postgraduate studies tuition fees, is available to start a PhD on this research topic in September 2004 within the Nuclear Physics group at the University of Liverpool. The research work will involve running experiments at overseas facilities (GANIL, GSI and NSCL/MSU), analysing experimental data at Liverpool and presenting the results at EU summer schools and international nuclear physics conferences. UK and EU students with an undergraduate Physics degree (such as a Masters of Physics or other equivalent EU qualification) are encouraged to apply by contacting Dr Marielle Chartier (see contact information below).

More information on the Liverpool Nuclear Physics Research group is available at http://ns.ph.liv.ac.uk as well as more information on PhD studies in the Physics Department of the University of Liverpool at http://www.ph.liv.ac.uk/admissions/postgraduate/postgraduate.html.

Contact Information:

Dr Marielle Chartier

Department of Physics Tel: +44 (0)151 794 6775

Oliver Lodge Laboratory (Room 412) Fax: +44 (0)151 794 3348

Oxford Street E-mail: chartier@liverpool.ac.uk

Liverpool L69 7ZE Web: http://ns.ph.liv.ac.uk/~mc/

United Kingdom