Nuclear structure and reactions

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Prof Steven Karataglidis joined the department of Physics on April 1, 2010. This is not quite indicative of any omen with regards to his tenure, given the date, but rather just a curious coincidence. Prof Karataglidis’ expertise lies in both Nuclear Structure and Reaction Theory, and the overlap between them, and works with colleagues around the world, both in theory and experiment, to gain a better understanding of that still most elusive of creatures: the atomic nucleus. He heads the Nuclear Structure and Reactions Group. Prof Karataglidis obtained his PhD from the University of Melbourne (Australia) in 1995, after which he had several postings around the world at various labs and universities (Michigan State University, TRIUMF, Los Alamos National Laboratory, CEA), before coming to South Africa in 2006 to join the Department of Physics and Electronics at Rhodes University. He became Head of that Department in 2009 and stayed at that post for a little over a year before coming to Johannesburg. During this time, he also became Head of the Programme Advisory Committee at iThemba Labs (Faure), a post which he held until April 2011. His colleagues are from around the world: the University of Melbourne; the University of Padova (Italy); the University of Manitoba (Canada); CEA (France); Tohoku University (Japan); among others. His most fruitful collaboration is with his former thesis advisor from Melbourne, Prof Ken Amos, a recent visitor to the University of Johannesburg, and with whom he has published almost 50 papers. The nucleus is an elusive beast: a many-nucleon (proton and neutron) system which can only be studied through reactions. But this is a catch-22: the purpose of the reactions is to gain knowledge of its structure but, to understand the reactions, one needs to know a priori its structure. This double-edged sword is where the problem lies, and can only be done through modelling. Prof Karataglidis uses both structure and reaction theory to work towards that end. The microscopic theories of scattering he has developed with his colleagues overseas, in particular, has shed new light on the structures of exotic nuclei (those that decay a short time after being formed in the laboratory). For halo nuclei, where one or two nucleons lie well outside the nuclear core, forming an odd bound system, the work has shown that the nucleon density forming the halo is depleted in the core. This is contrary to the view of cluster models, which hold that the core remains unchanged from those of stable nuclei. A proper many-body understanding is needed, and the large- scale shell model work on the structure side of Prof Karataglidis’ research has proved essential. 2011 marks the centenary of the discovery of the nucleus by Ernest Rutherford. After 100 years we are much closer in understanding what makes the nucleus tick, but there is still much work ahead in trying to unlock its secrets.