Workshop for young scientists with research interests focused on physics at FAIR

The field of nuclear physics is interested in the understanding of the properties of nuclei in and beyond the drip-line, especially the last decade the interest in research on halo and non-bound nuclei has been growing fast [1, 2]. This contribution is about a study of the unbound system 13Be produced from a 14B (p, 2p) reaction at high energy. The experiment was performed in complete kinematics using the R3B setup in Cave C at GSI. A primary beam of 40Ar at energy 490 MeV/u was let to impinge on a Beryllium target producing a mixed beam, which was separated in the fragment separator (FRS) before reaching the reaction target and the detection setup. As incoming nuclei the 14B was selected and after a p2p knockout reaction on CH2, the products of the unbound nuclei of interest 13Be was selected in the detector set-up . The isotope 13Be has a half-life in the order of 10-21 s, not allowing us to detect it directly, forcing us to look for the 12Be+n system. The invariant mass technique is used in the analysis in order to reconstruct the relative energy of the 12Be+n system. The reconstructed excitation spectra combined with the measurement of the gamma emitted from the excited 12Be fragments permits us to extract information about the 13Be structure. In this contribution these results will be explained together with a comparison to the latest published data, [3, 4], in order to reach a conclusion about the shell structure of 13Be. For the future R3B experiments at FAIR a new calorimeter, CALIFA, optimized for (p, 2p) reaction is being constructed [5]. For the front end-cap of CALIFA a demonstrator CEPA4 [6] is currently being tested. The main results and the future applications of the new detection technique used in the framework of probing unbound nuclei will be discussed. 1) H. Simon, Phys., Scr. T 152, 014024 (2013). 2) T. Baumann et al., Rep. Prog. Phys.75, 036301(2012). 3) Yu. Aksyutina et al. ,Phys. Rev. C 87, 064316 (2013). 4) G. Randisi et al., Phys. Rev. C. 89 034320 (2014). 5) D. Cortina-Gil et al., Technical report for the CALIFA Barrel (2011). 6) O. Tengblad et al. NIM A 704 19-26(2013).