Contribution to the study of electromagnetic transitions in deformed nuclei

This work deals with the interaction between the nucleus and the electromagnetic field. We have adapted the Nilsson formalism to deformed uneven-uneven nuclei. We have studied the probability of gamma transitions and energy levels. In the first chapter we have recalled the improvements brought successively in nuclear models to describe electromagnetic transitions, we begin with the spherical shell model, then present the rotational model and end with the unified model. We have applied the unified model to deformed uneven-uneven nuclei in order to compute probability transitions and energy levels. We have set an experiment to compare computed values and experimental data. Our gamma spectrometry equipment is composed of NaI(Tl) crystals and EMI-1954 photomultipliers. We have tested our method by studying the gamma rays appearing during the decay reaction: 233Pa → 233U. We have measured the energy levels of 234Pa and the Nilsson formalism appears to give good results for low energy levels. We have also studied the decay reaction: 231Pa → 227Ac, we give detailed gamma spectra and a preliminary energy level scheme but the interpretation of the energy levels with the unified model is all the more complicated because of the high density of levels between 0 and 130 KeV