The neutron capture cross section of (206)Pb has been measured at the CERN n_TOF spectrometer using a setup of two C(6)D(6) detectors. In the energy interval from 1 eV to 600 keV the cross section is dominated by resonances, which were analyzed via the R-matrix analysis code SAMMY. In the relevant energy ranges for stellar nucleosynthesis, i. e., at thermal energies of kT = 8 keV and kT = 23 keV, the present Maxwellian average cross section differs by 20% and 9% from the recommended values of Bao et al respectively. From the new cross section the s-abundance of (206)Pb could be reliably determined as 70( 4)%. This result is of importance in order to test and constrain r-process abundance calculations in the actinide region, because the r-process portion of (206)Pb is dominated by alpha-back decays of short-lived transbismuth isotopes.
The measurement of the 206Pb(n, γ) cross section and stellar implications
MASSIMI, CRISTIAN;VANNINI, GIANNI;
2008
Abstract
The neutron capture cross section of (206)Pb has been measured at the CERN n_TOF spectrometer using a setup of two C(6)D(6) detectors. In the energy interval from 1 eV to 600 keV the cross section is dominated by resonances, which were analyzed via the R-matrix analysis code SAMMY. In the relevant energy ranges for stellar nucleosynthesis, i. e., at thermal energies of kT = 8 keV and kT = 23 keV, the present Maxwellian average cross section differs by 20% and 9% from the recommended values of Bao et al respectively. From the new cross section the s-abundance of (206)Pb could be reliably determined as 70( 4)%. This result is of importance in order to test and constrain r-process abundance calculations in the actinide region, because the r-process portion of (206)Pb is dominated by alpha-back decays of short-lived transbismuth isotopes.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
