The focus of my research is centered on the study of exotic nuclei and the most efficient ways to unravel their properties. It is now well established that these radioactive nuclei - which depart from the usual balance of the number of protons and neutrons - have very different properties than the stable ones. Their structures, shapes and modes of excitation can reveal new phenomena, such as haloes or molecular states for instance, that are essential to our understanding of the forces that bind nuclei together via comparison with theoretical models. Finding the most sensitive and relevant experimental methods to reveal these phenomena has been the focus of my career since its beginning.
More specifically, I am conducting an experimental program aimed at using and studying in detail one of the most successful type of reactions used to study the structure of very rare exotic nuclei. These so-called knockout reactions are peripheral collisions where one or two nucleons at most are removed from a fast moving projectile. The aim of my program is to understand the reaction mechanisms that take place during such collisions, and validate the theory that is used to model them in order to deduce useful information on the structure of both the projectile and residual nuclei. A very interesting use of knockout reaction that I am pursuing is to map the wave function composition of light nuclei located in the p-shell, for which calculations from first principles are now available. Studying these light radioactive isotopes, several of them at the edge of being unbound, is paramount to test these new theories and guide their development.
In addition to fast beams and knockout reactions techniques, I am developing a new type of detector particularly well designed for lower energy collisions, such as transfer reactions or resonant scattering for instance. Low energy reactions require the use of very thin targets to preserve the characteristics of the emitted particles. This severely limits the sensitivity of such measurements, as the low number of nuclei in the target must be compensated by large intensities in the beams. The Active Target Time Projection Chamber, or AT-TPC, is a novel type of detector where the gas volume is at the same time a target and a detector medium. By literally detecting the reaction within the target itself, this new technique alleviates the shortcomings of the traditional solid target method. This detector is especially well suited for the future radioactive re-accelerated beams of the ReA3 linear accelerator, planned to be operational by the end of 2013. The AT-TPC is expected to be ready for experiments at about the same time.
This two-dimensional spectrum shows events recorded during a knockout reaction where a proton was removed from a 90 MeV/u Carbon-9 projectile. The energies of the resulting Boron-8 (horizontal) and proton (vertical) show two distinct regions corresponding to elastic and inelastic breakup processes.
New direct reaction: two-proton knockout from neutron-rich nuclei, D. Bazin, B. A. Brown, C. M. Campbell, …, Physical Review Letters 91, (2003) 012501
Mechanisms in knockout reactions, D. Bazin, R. J. Charity, R. T. de Souza, …, Physical Review Letters 102, (2009) 232501
Prototype AT-TPC: Toward a new generation active target time projection chamber for radioactive beam experiments, D. Suzuki, M. Ford, D. Bazin, W. Mittig, …, Nuclear Instruments and Methods in Physics Research A 691 (2012) 39