Measurement of the radiative neutron capture cross section of 206Pb and its astrophysical implications

C. Domingo-Pardo , U. Abbondanno , G. Aerts (1) , H. Alvarez , F. Alvarez-Velarde , S. Andriamonje , J. Andrzejewski , P. Assimakopoulos , L. Audouin , G. Badurek , P. Baumann (2) , F. Becvar , E. Berthoumieux (1) , S. Bisterzo , F. Calvino , M. Calviani , D. Cano-Ott , R. Capote , C. Carrapico , P. Cennini , V. Chepel , E. Chiaveri , N. Colonna , G. Cortes , A. Couture , J. Cox , M. Dahlfors , S. David (2) , I. Dillman , R. Dolfini , W. Dridi (1) , I. Duran , C. Eleftheriadis , M. Embid-Segura , L. Ferrant (3) , Anthony Ferrari , R. Ferreira-Marques , L. Fitzpatrick , H. Frais-Koelbl , K. Fujii , W. Furman , R. Gallino , I. Goncalves , E. Gonzalez-Romero , A. Goverdovski , F. Gramegna , E. Griesmayer , C. Guerrero , F. Gunsing (1) , B. Haas (4) , R. Haight , M. Heil , A. Herrera-Martinez , M. Igashira , M. Isaev , E. Jericha , F. Kappeler , Y. Kadi , D. Karadimos , D. Karamanis , M. Kerveno (2) , V. Ketlerov , P. Koehler , V. Konovalov , E. Kossionides , M. Krticka , C. Lamboudis , H. Leeb , A. Lindote , I. Lopes , M. Lozano , S. Lukic (2) , J. Marganiec , S. Marrone , C. Massimi , P. Mastinu , A. Mengoni , P.M. Milazzo , C. Moreau , M. Mosconi , F. Neves , H. Oberhummer , M. Oshima , S. O'Brien , J. Pancin (1) , C. Papachristodoulou , C. Papadopoulos , C. Paradela , N. Patronis , A. Pavlik , P. Pavlopoulos , L. Perrot (1) , R. Plag , A. Plompen , A. Plukis (1) , A. Poch , C. Pretel , J. Quesada , T. Rauscher , R. Reifarth , M. Rosetti , C. Rubbia , G. Rudolf (2) , P. Rullhusen , J. Salgado , L. Sarchiapone , I. Savvidis , C. Stephan (3) , G. Tagliente , J.L. Tain , L. Tassan-Got (3) , L. Tavora , R. Terlizzi , G. Vannini , P. Vaz , A. Ventura , D. Villamarin , M.C. Vincente , V. Vlachoudis , R. Vlastou , F. Voss , S. Walter , H. Wendler , M. Wiescher , K. Wisshak

1 DAPNIA - Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée
2 DRS-IPHC - Département Recherches Subatomiques
3 IPNO - Institut de Physique Nucléaire d'Orsay
4 CENBG - Centre d'Etudes Nucléaires de Bordeaux Gradignan

The (n, gamma) cross section of 206Pb has been measured at the CERN n_TOF facility with high resolution in the energy range from 1 eV to 600 keV by using two optimized C6D6 detectors. In the investigated energy interval about 130 resonances could be observed, from which 61 had enough statistics to be reliably analyzed via the R-matrix analysis code SAMMY. Experimental uncertainties were minimized, in particular with respect to (i) angular distribution effects of the prompt capture gamma-rays, and to (ii) the TOF-dependent background due to sample-scattered neutrons. Other background components were addressed by background measurements with an enriched 208Pb sample. The effect of the lower energy cutoff in the pulse height spectra of the C6D6 detectors was carefully corrected via Monte Carlo simulations. Compared to previous 206Pb values, the Maxwellian averaged capture cross sections derived from these data are about 20% and 9% lower at thermal energies of 5 keV and 30 keV, respectively. These new results have a direct impact on the s-process abundance of 206Pb, which represents an important test for the interpretation of the cosmic clock based on the decay of 238U.

Mots clés: Neutron capture cross sections; Nuclear astrophysics; Pulse height weighting technique; C6D6 scintillation detectors; Monte Carlo simulations

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

C. Domingo-Pardo, U. Abbondanno, G. Aerts, H. Alvarez, F. Alvarez-Velarde, et al.. Measurement of the radiative neutron capture cross section of 206Pb and its astrophysical implications. Physical Review C, 2007, 76, pp.045805. ⟨10.1103/PhysRevC.76.045805⟩. ⟨in2p3-00165399⟩