Cross-Sections and Analyzing Powers in the 8- to 17-MEV Range for Neutron Scattering from IRON-54,56, NICKEL-58,60, NIOBIUM-93, and TIN-120.
Using standard time-of-flight techniques, differential cross section (sigma)((THETA)) and/or analyzing power A(,y)((THETA)) data have been acquired in the 20(DEGREES) to 160(DEGREES) angular range for: ('54,56)Fe and ('58,60)Ni, for neutron elastic scattering and inelastic scattering to the first 2('+) excited states, and for ('93)Nb and ('120)Sn, for neutron elastic scattering. For ('54)Fe and ('58)Ni, (sigma)((THETA)) data were measured at 17 MeV, and A(,y)((THETA)) data were measured at 10, 14, and 17 MeV. For ('56)Fe and ('60)Ni, A(,y)((THETA)) measurements were made at 10 MeV. The inelastic scattering A(,y)((THETA)) data for the Fe and Ni isotopes are for only a few selected angles. For ('93)Nb, (sigma)((THETA)) data were measured at 8, 10, 12, 14, and 17 MeV, and A(,y)((THETA)) data were measured at 10 and 14 MeV. Also, for ('93)Nb, nine (sigma)((THETA)) measurements have been made at 10 MeV for neutron elastic scattering at "small-angles" (1.8(DEGREES) to 15.9(DEGREES)). For ('120)Sn, A(,y)((THETA)) data were measured at 17 MeV. The absolute normalizations for the (sigma)((THETA)) measurements are made using n-p scattering measurements. The (sigma)((THETA)) and A(,y)((THETA)) data are corrected for finite geometry, attenuation, relative efficiency, and multiple scattering effects using Monte Carlo calculations. The data for ('54,56)Fe and ('58,60)Ni are combined with existing data for these isotopes to expand and refine previous coupled-channel analyses performed using the vibrational model with the ground and first excited states coupled. The ('93)Nb data are examined using a spherical optical model analysis, and comparisons are made to previous spherical optical model studies. The data for ('120)Sn are compared only to predictions of a previous coupled-channel analysis. Also, for incident neutron energies from 2 to 18 MeV, the first multi-bias absolute efficiency measurements are reported for the two main neutron detectors used in measuring the (sigma)((THETA)) and A(,y)((THETA)) data. The neutron detectors are filled with NE-213 and NE-218 liquid scintillator.
- Pub Date:
- Physics: Nuclear