Systematics of gamma decay through low-lying vibrational levels of even--even nuclei excited by (p,p') and (n,n') reactions

Technical Report · Thu Jun 30 04:00:00 EDT 1977

DOI:https://doi.org/10.2172/5349153· OSTI ID:5349153

Koopman, R P

A series of experiments was performed in which gamma-ray spectra were measured, using a Ge(Li) detector, for incident 7 to 26-MeV protons on the even-even vibrational nuclei /sup 56/Fe, /sup 62/Ni, /sup 64/Zn, /sup 108/Pd, /sup 110/Cd, /sup 114/Cd, /sup 116/Cd, /sup 116/Sn, /sup 120/Sn, and /sup 206/Pb, and for incident 14-MeV neutrons on natural Fe, Ni, Zn, Cd, Sn, and Pb. These measurements yielded gamma-ray cross sections from which it was inferred that almost all of the gamma cascades from (p,p') and (n,n') reactions passed down through the first 2/sup +/ levels. Consequently, the strength of the 2/sup +/ ..-->.. 0/sup +/ gamma transitions were found to be an indirect measure of the (p,p') or (n,n') cross sections. Several types of nuclear model calculations were performed and compared with experimental results. These calculations included coupled-channel calculations to reproduce the direct, collective excitation of the low-lying levels, and statistical plus pre-equilibrium model calculations to reproduce the (p,p') and the (n,n') cross sections for comparison with the 2/sup +/ ..-->.. 0/sup +/ gamma measurements. The agreement between calculation and experiment was generally good except at high energies, where pre-equilibrium processes dominate (i.e. around 26-MeV). Here discrepancies between calculations from the two different pre-equilibrium models and between the data and the calculations were found. Significant isospin mixing of T/sub greater than/ into T/sub less than/ states was necessary in order to have the calculations match the data for the (p,p') reactions, up to about 18-MeV.

• Research Organization: California Univ., Livermore (USA). Lawrence Livermore Lab.
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5349153
• Report Number(s): UCRL-52275
• Country of Publication: United States
• Language: English

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BARYON REACTIONS
BARYONS
CADMIUM 110
CADMIUM 110 TARGET
CADMIUM 114
CADMIUM 114 TARGET
CADMIUM 116
CADMIUM 116 TARGET
CADMIUM ISOTOPES
CHARGED-PARTICLE REACTIONS
COUPLED CHANNEL THEORY
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
EVEN-EVEN NUCLEI
FERMIONS
GAMMA RADIATION
HADRON REACTIONS
HADRONS
HEAVY NUCLEI
INELASTIC SCATTERING
INTERMEDIATE MASS NUCLEI
IONIZING RADIATIONS
IRON 56
IRON 56 TARGET
IRON ISOTOPES
ISOSPIN
ISOTOPES
LEAD 206
LEAD 206 TARGET
LEAD ISOTOPES
MATHEMATICAL MODELS
NEUTRON REACTIONS
NEUTRONS
NICKEL 62
NICKEL 62 TARGET
NICKEL ISOTOPES
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
NUCLEONS
PALLADIUM 108
PALLADIUM 108 TARGET
PALLADIUM ISOTOPES
PARTICLE PROPERTIES
PRECOMPOUND-NUCLEUS EMISSION
PROTON REACTIONS
PROTONS
RADIATIONS
SCATTERING
STABLE ISOTOPES
STATISTICAL MODELS
TARGETS
TIN 116
TIN 116 TARGET
TIN 120
TIN 120 TARGET
TIN ISOTOPES
ZINC 64
ZINC 64 TARGET
ZINC ISOTOPES