EURORIB'15

Very recent theoretical and experimental investigations [1,2,3] show the possible presence of exotic structures, such as molecular states or triangle configurations, in Beryllium and Carbon neutron-rich isotopes. These structures are characterized by very large deformation, with alpha clusters bounded by valence neutrons [1,3]. We studied the spectroscopy of 10Be and 16C nuclei by using projectile sequential break-up reactions. The exotic beams were produced by the FRIBs facility at INFN – LNS [4,5]. Break-up products have been detected and identified by using the Chimera 4pi array [6], thanks to its good angular segmentation and its total azimuthal coverage. From the study of 1,2H,12C(10Be,6He+4He), 1,2H,12C(16C,6He+10Be), 1,2H,12C(16C,6He+6He+4He) reactions, we reconstructed 10Be and 16C excitation energy spectra. Peaks on these spectra may indicate the presence of excited states characterized by cluster structure. From the analysis of experimental spectra we found some peaks corresponding to excited states of 10Be known in literature and a new possible state at about 13.5 MeV. Investigations of the corresponding 6He-4He angular correlations revealed a possible 6+ assignement for this state, in agreement with the recent work [7]. In this case, it may represent a further member of the 10Be molecular rotational band [3]. Finally, from binary (6He+10Be) and ternary (4He+6He+6He) cluster decompositions of 16C we found, respectively, the indication of possible new states at about 20.6 MeV and 34 MeV. To continue the experimental investigations here discussed, a new experiment, with higher angular resolution and better statistics, has been performed very recently at LNS by using the Farcos array [8]. References [1] W. von Oertzen, M. Freer and Y. Kanada-En’yo, Phys. Rep. 432 (2006) 43 [2] Y. Kanada-En’yo, Phys. Rev. C 91 (2015) 034303. [3] M. Freer et al, Phys. Rev. Lett. 96 (2006) 042501 [4] G. Raciti et al, Nucl. Instrum. Meth. Phys. Res. B 266 (2008) 4632 [5] L. Acosta et al, Nucl. Instrum. Meth. Phys. Res. A 715 (2013) 56 [6] A. Pagano, Nucl. Phys. News 22 (2012) 25 [7] G.V. Rogachev et al, J. Phys. Conf. Ser. 569 (2014) 012004 [8] L. Acosta et al, IEEE NSS/MIC (2012) 1547-1553