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 00:00:00 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: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5349153
• Report Number(s): UCRL-52275; TRN: 78-001985
• Resource Relation: Other Information: Thesis
• Country of Publication: United States
• Language: English

Related Subjects

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