Ambiguities in the elastic scattering of 8 MeV neutrons from adjacent nuclei
Ratios of the cross sections for elastic scattering of 8 MeV neutrons from adjacent nuclei are measured over the angular range {approx}20{degree} {minus} 160{degree} for the target pairs {sup 51}V/Cr, {sup 59}Co/{sup 58}Ni, Cu/Zn, {sup 89}Y/{sup 93}Nb, {sup 89}Y/Zr, {sup 93}Nb/Zr, In/Cd and {sup 209}Bi/Pb. The observed ratios vary from unity by as much as a factor of {approx}2 at some angles for the lighter target pairs. Approximately half the measured ratios are reasonably explained by a simple spherical optical model, including size and isospin contributions. In all cases, the geometry of the real optical--model potential is essentially the same for neighboring nuclei, and the real--potential strengths are consistent with the Lane model. In contrast, it is found that the imaginary potential may be quite different for adjacent nuclei, and the nature of this difference is examined. It is shown that the spin--spin interaction has a negligible effect on the calculation of the elastic--scattering ratios, but that channel coupling, leading to a large reorientation of the target ground state, can be a consideration, particularly in the {sup 59}Co/{sup 58}Ni case. In the A {approx} 50--60 region the calculated ratios are sensitive to spin--orbit effects, but the exact nature of this interaction must await more definitive polarization measurements. The measured and calculated results suggest that the concept of a conventional global'' or even regional'' optical potential provides no more than a qualitative representation of the physical reality for a number of cases. 48 refs., 14 figs., 3 tabs.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- DOE/ER
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 6933934
- Report Number(s):
- ANL/NDM-114; ON: DE90009518; TRN: 90-010793
- Country of Publication:
- United States
- Language:
- English
Similar Records
Excitation functions of some (n,p) and (n,{alpha}) reactions from threshold to 16 MeV
A determination of the asymptotic D-state to S-state ratio for {sup 3}He via the {sup 63}Cu(d,{sup 3}He){sup 62}Ni and {sup 89}Y(d,{sup 3}He){sup 88}Sr reactions
Related Subjects
NUCLEI
NEUTRON REACTIONS
ANGULAR DISTRIBUTION
BRANCHING RATIO
DIFFERENTIAL CROSS SECTIONS
ELASTIC SCATTERING
EXPERIMENTAL DATA
GROUND STATES
ISOSPIN
J-J COUPLING
L-S COUPLING
MEV RANGE 01-10
NUCLEAR DATA COLLECTIONS
OPTICAL MODELS
BARYON REACTIONS
COUPLING
CROSS SECTIONS
DATA
DISTRIBUTION
ENERGY LEVELS
ENERGY RANGE
HADRON REACTIONS
INFORMATION
INTERMEDIATE COUPLING
MEV RANGE
NUCLEAR REACTIONS
NUCLEON REACTIONS
NUMERICAL DATA
PARTICLE PROPERTIES
SCATTERING
651000* - Nuclear Physics