Study of neutron rich Carbon and Oxygen nuclei up to drip line

In-beam γ-spectroscopy using fragmentation reactions of radioactive beams have been performed in order to study the structure of excited states in neutron rich oxygen and carbon isotopes. For the produced fragments, γ-ray energies, intensities and γ-γ coincidences have been measured. The experiment was performed at GANIL. New γ-lines have been identified and placed in level schemes for 17-20C. The non observation of any γ-ray in 23,24O suggests that their first excited states lie above the neutron threshold. These results are discussed in the framework of shell model calculations