Rapid increase in prescission giant-dipole-resonance {gamma}-ray emission with bombarding energy

Journal Article · Mon May 01 04:00:00 EDT 1995 · Physical Review, C

DOI:https://doi.org/10.1103/PhysRevC.51.2597· OSTI ID:44697

Hofman, D J; Back, B B; Paul, P ^[1]

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1. Department of Physics, State University of New York at Stony Brook, Stony Brook, New York 11794 (United States)

A rapid increase with energy has been observed in the emission of prescission giant dipole resonance (GDR) {gamma} rays in excited Th and Cf nuclei formed in the {sup 16}O+{sup 208}Pb and {sup 32}S+{sup nat}W,{sup 208}Pb reactions, which is not explained by the normal reaction dynamics near the barrier. This increase occurs over a narrow excitation energy range of {ital E}{sub exc}=40--60 MeV for the {sup 16}O+{sup 208}Pb reaction and {ital E}{sub exc}=70--90 MeV for the {sup 32}S-induced reactions. Below the transition energy the {gamma}-ray spectra can be described by the standard statistical model, whereas inclusion of an increasingly strong nuclear dissipation is required to account for the data at higher excitation energies. For the {sup 16}O+{sup 208}Pb reaction a fit to the GDR {gamma}-ray spectra and evaporation residue cross sections is used to extact the temperature dependence of the linear dissipation parameter.

• DOE Contract Number: FG02-93ER40780
• OSTI ID: 44697
• Journal Information: Physical Review, C, Journal Name: Physical Review, C Journal Issue: 5 Vol. 51; ISSN PRVCAN; ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
CALIFORNIUM 251
DIPOLES
ENERGY DEPENDENCE
EXCITED STATES
GAMMA RADIATION
GIANT RESONANCE
LEAD 208 TARGET
OXYGEN 16 REACTIONS
STATISTICAL MODELS
SULFUR 32 REACTIONS
TEMPERATURE DEPENDENCE
THORIUM 232
TUNGSTEN 184 TARGET