The radiative neutron capture cross section of 207Pb has been measured at the CERN neutron lime of flight installation n_TOF using the pulse height weighting technique in the resolved energy region. The measurement has been performed with an optimized setup of two C6D6 scintillation detectors, which allowed us to reduce scattered neutron backgrounds down to a negligible level. Resonance parameters and radiative kernels have been determined for 16 resonances by means of an R-matrix analysis in the neutron energy range from 3 keV to 320 keV. Good agreement with previous measurements was found at low neutron energies, whereas substantial discrepancies appear beyond 45 keV. With the present results, we obtain an s-process contribution of 77 plus or minus 8% to the solar abundance of 207Pb. This corresponds to an r-process component of 23 plus or minus 8%, which is important for deriving the U/Th ages of metal poor halo stars.
Resonance Capture Cross Section of 207Pb
Ventura, A.;
2006-11-01
Abstract
The radiative neutron capture cross section of 207Pb has been measured at the CERN neutron lime of flight installation n_TOF using the pulse height weighting technique in the resolved energy region. The measurement has been performed with an optimized setup of two C6D6 scintillation detectors, which allowed us to reduce scattered neutron backgrounds down to a negligible level. Resonance parameters and radiative kernels have been determined for 16 resonances by means of an R-matrix analysis in the neutron energy range from 3 keV to 320 keV. Good agreement with previous measurements was found at low neutron energies, whereas substantial discrepancies appear beyond 45 keV. With the present results, we obtain an s-process contribution of 77 plus or minus 8% to the solar abundance of 207Pb. This corresponds to an r-process component of 23 plus or minus 8%, which is important for deriving the U/Th ages of metal poor halo stars.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
