NEUTRON RADIATIVE CAPTURE IN NA,AL,FE AND NI FROM 1-KEV TO 200-KEV

Neutron radiative capture in Na, Al, Fe, and Ni has been measured from 100 eV to 200 keV with a 1.25-m-diam liquid scintillator detector at the Rensselaer LINAC Laboratory. Radiation widths were determined for those resonances whose neutron widths are well known, while the resonance capture areas (σ0Γγ) were determined for most of the other resonances. Considerably more resonances were observed in the capture measurements upon Fe and Ni than had been observed in total cross-section measurements. It is reasonable to assign most if not all of these previously undetected resonances to p-wave neutrons, and from these data p-wave strength functions of (0.10±0.04) × 10-4 and (0.04±0.03) × 10-4 were determined, respectively, for Fe56 and Ni58. These strength functions are probably just upper limits to the true p-wave strength functions and are an order of magnitude smaller than optical-model predictions. © 1969 The American Physical Society.