Neutron transmission and capture measurements and analysis of /sup 60/Ni from 1 to 450 keV

Technical Report · Mon Nov 01 04:00:00 EST 1982

DOI:https://doi.org/10.2172/6711144· OSTI ID:6711144

Perey, C M; Harvey, J A; Macklin, R L; Winters, R R; Perey, F G

High-resolution transmission and capture measurements of /sup 60/Ni-enriched targets have been made at the Oak Ridge Electron Linear Accelerator (ORELA) from a few eV to 1800 keV in transmission and from 2.5 keV to 5 MeV in capture . The transmission data from 1 to 450 keV were analyzed with a multi-level R-matrix code which uses the Bayes' theorem for the fitting process. This code provides the energies and neutron widths of the resonances inside the 1- to 450-keV region as well as a possible parameterization for outside resonances to describe the smooth cross section in this region. The capture data were analyzed with a least-squares fitting code using the Breit-Wigner formula. From 2.5 to 450 keV, 166 resonances were seen in both sets of data. Correspondence between the energy scales shows a discontinuity around 300 keV which makes the matching of resonances at higher energies difficult. Eighty-nine resonances were seen in the capture data only. Average parameters for the 30 observed s-wave resonances were deduced. The average level spacing D/sub 0/ was found to be equal to 15.2 +- 1.5 keV, the strength function, S/sub 0/, equal to (2.2 +- 0.6) x 10/sup -4/ and the average radiation width, GAMMA/sub ..gamma../, equal to 1.30 +- 0.07 eV. The staircase plot of the reduced level widths and the plot of the Lorentz-weighted strength function averaged over various energy intervals show possible evidence for doorway states. The level densities calculated with the Fermi-gas model for l = 0 and for l > 0 resonances were compared with the cumulative number of observed resonances, but the analysis is not conclusive. The average capture cross section as a function of the neutron incident energy is compared to the tail of the giant electric dipole resonance prediction.

• Research Organization: Oak Ridge National Lab., TN (USA)
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 6711144
• Report Number(s): ORNL-5893; ENDF-330; ON: DE83003190
• Country of Publication: United States
• Language: English

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BARYON REACTIONS
BARYONS
BREIT-WIGNER FORMULA
CAPTURE
COMPUTER CALCULATIONS
CROSS SECTIONS
DATA
DATA ANALYSIS
ELEMENTARY PARTICLES
ELEMENTS
ENERGY DEPENDENCE
ENERGY RANGE
ENERGY-LEVEL DENSITY
EXPERIMENTAL DATA
FERMIONS
FUNCTIONS
GIANT RESONANCE
HADRON REACTIONS
HADRONS
INFORMATION
KEV RANGE
LEVEL WIDTHS
MATRICES
METALS
MEV RANGE
MEV RANGE 01-10
NEUTRAL-PARTICLE TRANSPORT
NEUTRON REACTIONS
NEUTRON TRANSPORT
NEUTRONS
NICKEL
NICKEL 60 TARGET
NUCLEAR REACTIONS
NUCLEON REACTIONS
NUCLEONS
NUMERICAL DATA
PARTIAL WAVES
R MATRIX
RADIATION TRANSPORT
RESONANCE
S WAVES
STRENGTH FUNCTIONS
TARGETS
TRANSITION ELEMENTS
TRANSMISSION