Production and $\beta$ half-lives of heavy neutron-rich nuclei approaching the r-process path at N=126

J. Benlliure , H. Alvarez-Pol , T. Kurtukian Nieto , A.I. Morales , E. Casarejos , D. Cortina-Gil , J. Pereira , F. Becker , I. Borzov , T. Enqvist , D. Henzlova , K. Langanke , G. Martínez-Pinedo , K.H. Schmidt , O. Yordanov , Bertram Blank (1) , J. Giovinazzo (1) , B. Jurado (1) , L. Audouin (2) , P. Napolitani (2) , B. Fernandez (3) , F. Rejmund (3)

1 CENBG - Centre d'Etudes Nucléaires de Bordeaux Gradignan
2 IPNO - Institut de Physique Nucléaire d'Orsay
3 GANIL - Grand Accélérateur National d'Ions Lourds

Fragmentation reactions of relativistic 238U and 208 Pb projectiles have been used to investigate the production of heavy neutron-rich nuclei approaching the r-process waiting point at A≈195. The relativistic energies, together with the use of a high resolving-power magnetic spectrometer were key conditions for the unambiguous identification of nuclei in the region of interest. Using this technique we were able to identify 73 new heavy neutron-rich nuclei expanding considerably the north-west frontier of the chart of nuclide. Moreover, we were able to determine the half lives of 13 of those nuclide. The measured values are signific antly shorter than the predictions used for r-process model calculations. The confirmation of these results for r-process nuclei at A≈195 would indicate that the r-process at this point is faster than expected, leading to a larger production of the heaviest nuclei.

Domaines: Physique Nucléaire Expérimentale [nucl-ex]; Astrophysique stellaire et solaire [astro-ph.SR]; Astrophysique stellaire et solaire [astro-ph.SR]

J. Benlliure, H. Alvarez-Pol, T. Kurtukian Nieto, A.I. Morales, E. Casarejos, et al.. Production and $\beta$ half-lives of heavy neutron-rich nuclei approaching the r-process path at N=126. Proceedings of the 11th Symposium on Nuclei in the Cosmos, Jul 2010, Heidelberg, Germany. pp.084. ⟨in2p3-00672525⟩