Experimental Nuclear Physics

The experimental nuclear physicists at Surrey perform their research at a range of facilities around the world, such as GSI (Germany), GANIL (France), CERN (Switzerland), Canberra (Australia) and TRIUMF (Canada).

Interests of the group include gamma-ray and charged-particle spectroscopy, especially their use to look at exotic forms of nuclear matter: nuclei with extreme values of neutron-to-proton ratio, nuclei with unusual shapes, and nuclei at high angular momentum.

One particular area of study is the use of high-energy projectile fragmentation to populate states in heavy neutron-rich nuclei.  The decay radiations from long-lived excited states (isomers) allow the investigation of nuclei that are inaccessible using other methods.  The observation of isomeric decays provides a unique tool for learning about the reaction mechanism of projectile fragmentation. It is also possible to observe individual isomeric ions as they circulate in a storage ring.

The study of spin-trap isomers is a speciality of the group, from both a theoretical and an experimental point of view.  The use of radioactive ion beams produced by projectile fragmentation or the ISOL method is the current focus of our isomer studies.  With the advent of new high-intensity radioactive ion beams, predicted isomers in neutron-rich nuclei in the mass 180-210 region are becoming accessible for the first time.  The study of these isomeric states is motivated by their ability to probe the underlying nuclear structure properties, such as shell gaps, pairing and superfluidity, residual nucleon-nucleon interactions, the stability of axially-symmetric shapes, and shape co-existence.

Amongst lighter nuclei, the group has a record of pioneering new ways to access the physics of exotic nuclei using radioactive beams. The current focus is on the use of nucleon transfer reactions, and especially those initiated by radioactive beams incident on deuteron targets and transferring neutrons to and from the projectile. The primary motivation is to observe the changes in the energies of orbitals, and therefore changes in the nuclear magic numbers, as nuclei evolve from near stability to being very asymmetric in their neutron-proton ratio. This can then explain changes in structure far from stability and in some cases also allows us to measure quantities that are important in understanding nuclear astrophysical processes.

Please contact Phil Walker for further information about experimental nuclear physics research at Surrey.