Charged particles as probes to study entrance channel effects in the composite system {sup 164}Yb

Conference · Mon Jun 01 04:00:00 EDT 1992

OSTI ID:10143098

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

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1. Washington Univ., St. Louis, MO (United States). Dept. of Chemistry
2. Oak Ridge National Lab., TN (United States)

We present preliminary results in a study of entrance channel effects by comparing measured charged particles and {gamma}-ray multiplicities in coincidence with residue nuclei (identified by discrete transitions) from both mass symmetric and symmetric reactions. The systems studiede are {sup 64}Ni + {sup 100}Mo and {sup 148}Sm, both of which would produce the {sup 164}Yb compound nucleus with 52 MeV of excitation energy. In the ({alpha}2n) exit channel, the center of mass {alpha}-particle angular distribution is symmetric around 90{degrees} in the Ni-induced reaction, indicating emission from a fully equilibrated system. Furthermore, the extracted anisotropies show no evidence for an enhancement of {alpha}-particle emission in the low energy region, which indicates emission from a nearly spherical system. However, the corresponding angular distribution of the {sup 16}O-induced reaction shows a strong forward component, which is a clear signature of a non-statistical contribution to the residue cross-section. This non-statistical component has to be taken into account when comparing decay modes of a compound nucleus formed in different entrance channels.

• Research Organization: Oak Ridge National Lab., TN (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-84OR21400; FG02-87ER40316; FG02-88ER40406
• OSTI ID: 10143098
• Report Number(s): CONF-920113--4; ON: DE92013223
• Country of Publication: United States
• Language: English

Related Subjects

663450
663560
663570
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
A = 150-189
A = 90-149
ALPHA DECAY
ALPHA PARTICLES
ANGULAR DISTRIBUTION
COMPOUND NUCLEI
CROSS SECTIONS
ERBIUM 158
HEAVY ION FUSION REACTIONS
HEAVY-ION-INDUCED REACTIONS AND SCATTERING
MOLYBDENUM 100 TARGET
NICKEL 64 REACTIONS
OXYGEN 16 REACTIONS
SAMARIUM 148 TARGET
YTTERBIUM 164