Probing the isospin structure of short-lived excited nuclear states using the transient field technique

In the vicinity of the Z=50 and N=82 shell closures unexpected findings in the behaviour of the electric quadrupole transition probabilities of excited nuclear states, e.g. the surplus of B(E2) strengths in neutron deficient Sn isotopes or the surprisingly small B(E2,0+1→2+1) in 136Te, have triggered many theoretical investigations and further experiments. However, model predictions could only partially explain the observed behaviour and the isospin structure of the excitations in the nuclear valence shell is discussed controversially, e.g. in 136Te where results from calculations differ significantly. Due to their single-particle nature magnetic dipole moments grant access to the missing experimental information and we have therefore measured g factors of the first excited states in relevant even Sn, Te, Xe and Ba isotopes in stable and radioactive beam experiments. The short lifetimes in the range of a few ps are experimentally challenging and solely the technique of transient magnetic fields can be applied. Achievements and results are discussed together with a presentation of experimental aspects and developments for the use of this technique with radioactive ion beams at low- and intermediate beam energies.