Search for entrance channel effects in the decay of the [sup 164]Yb compound nucleus at [ital E][sup *][approx]54 MeV

Journal Article · Wed Dec 01 00:00:00 EST 1993 · Physical Review, C (Nuclear Physics); (United States)

DOI:https://doi.org/10.1103/PhysRevC.48.2881· OSTI ID:5574517

Barreto, J L; Nicolis, N G; Sarantites, D G; Charity, R J; Sobotka, L G; Stracener, D W ^[1]; Hensley, D C; Beene, J R; Baktash, C; Halbert, M; Thoennessen, M ^[2]

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1. Department of Chemistry, Washington University, St. Louis, Missouri 63130 (United States)
2. Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 (United States)

The existence of entrance channel effects in the decay of [sup 164]Yb[sup *], formed at [ital E][sup *][approx]54 MeV in the reactions [sup 16]O+[sup 148]Sm and [sup 64]Ni+[sup 100]Mo is investigated. Evaporation residue cross sections, entry state [gamma]-ray fold distributions as well as energy and angular distributions of exit channel selected charged particles were obtained for each reaction, using 4[pi] detection systems for both particles and [gamma] rays. In the [sup 64]Ni-induced reaction, the center-of-mass [alpha]-particle angular distributions were found to be symmetric around 90[degree] indicating emission from a fully equilibrated compound nucleus. However, the corresponding angular distributions in the [sup 16]O-induced reaction show a forward component which exclusively affects the population of the [alpha][ital xn] residue channels. The [gamma]-ray fold distributions for the [alpha][ital xn] and [ital xn] channels show differences depending on the entrance channel as reported previously for similar systems. These differences can be understood in terms of contributions from the equilibrium decay of incompletely fused [sup 16]O with [sup 148]Sm and the mapping of the compound nucleus spin distributions, obtained from realistic fusion models, to the evaporation residue [gamma]-ray fold distributions. It is concluded that the initial population of the compound nucleus is the only reason for the observed differences in the decay of [sup 164]Yb[sup *] populated in these reactions.

• DOE Contract Number: FG02-88ER40406; FG02-87ER40316; AC05-84OR21400
• OSTI ID: 5574517
• Journal Information: Physical Review, C (Nuclear Physics); (United States), Vol. 48:6; ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
MOLYBDENUM 100 TARGET
NICKEL 64 REACTIONS
SAMARIUM 148 TARGET
OXYGEN 16 REACTIONS
YTTERBIUM 164
DECAY
ANGULAR DISTRIBUTION
CHARGED PARTICLES
COMPOUND NUCLEI
CROSS SECTIONS
GAMMA RADIATION
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
CHARGED-PARTICLE REACTIONS
DISTRIBUTION
ELECTROMAGNETIC RADIATION
ELECTRON CAPTURE RADIOISOTOPES
EVEN-EVEN NUCLEI
HEAVY ION REACTIONS
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IONIZING RADIATIONS
ISOTOPES
NUCLEAR REACTIONS
NUCLEI
RADIATIONS
RADIOISOTOPES
RARE EARTH NUCLEI
TARGETS
YTTERBIUM ISOTOPES
663450* - Heavy-Ion-Induced Reactions & Scattering- (1992-)
663570 - Nuclear Mass Ranges- A=150-189- (1992-)
663200 - Radioactivity & Electromagnetic Transitions- (1992-)