Fusion and fission properties of rapidly rotating nuclei /sup 40/Ar + /sup 238/U. -->. /sup 278/110 at E/sub cm/ = 291 MeV

Technical Report · Sat Jan 01 04:00:00 EST 1983

OSTI ID:5590543

Lesko, K T

Coincident fission fragments were detected to study the complete capture reaction, /sup 40/Ar + /sup 238/U ..-->.. /sup 278/110 ..-->.. f, at E/sub cm/ = 291 MeV (E/sub lab/ = 340 MeV). The detection system had a high efficiency to detect and subsequently veto events showing evidence of incomplete momentum transfer. The angular distribution of fission fragments was obtained between the center-of-mass angles of 119/sup 0/ and 164/sup 0/. The mass distributions of the fission fragments were also obtained for these angles. One non-coincident measurement made at theta/sub cm/ = 43.7/sup 0/ confirmed the symmetry of the angular distribution about 90/sup 0/. This study is distinguished from other recent studies by the use of a novel veto technique. This is the first measurement which has not been compromised by contamination with incomplete momentum-transfer reactions due to either pre-equilibrium emission or fission following deeply inelastic scattering. This is also the first investigation which reports detailed angular distributions with a majority (approx. 90%) of the capture cross section leading to nuclei having vanishing fission barriers. The rotating liquid-drop-model parameters were extracted from the data. The RLDM shapes along with statistical fission models, when applied to all partial waves, fail to reproduce the angular distributions. We interpret the angular distributions by applying statistical-equilibrium models and RLDM shapes for the nonvanishing fission-barrier partial waves and by assuming that the vanishing fission-barrier partial-wave contribution is given by l/sin theta. A l/sin theta distribution is expected for a system which has not reached complete statistical equilibrium and maintains a memory of its entrance channel, with the fission fragments being emitted in the reaction plane defined by the initial contact.

• Research Organization: Washington Univ., Seattle (USA)
• DOE Contract Number: AC06-81ER40048
• OSTI ID: 5590543
• Report Number(s): DOE/ER/40048-63-L3; ON: DE83015736
• Country of Publication: United States
• Language: English

Related Subjects

652025* -- Nuclear Properties & Reactions
A=220 & above
Experimental-- Nuclear Reactions & Scattering-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR DISTRIBUTION
ANGULAR MOMENTUM
ANGULAR MOMENTUM TRANSFER
ARGON 40 REACTIONS
CHARGED-PARTICLE REACTIONS
COINCIDENCE SPECTROMETRY
COMPOUND-NUCLEUS REACTIONS
CROSS SECTIONS
DATA
DEFORMATION
DISTRIBUTION
ELEMENT 110
ELEMENTS
ENERGY RANGE
EXPERIMENTAL DATA
FISSION
FISSION BARRIER
FISSION FRAGMENTS
FUSION REACTIONS
HEAVY ION REACTIONS
INFORMATION
LIQUID DROP MODEL
MASS SPECTRA
MATHEMATICAL MODELS
MEV RANGE
MEV RANGE 100-1000
MOMENTUM TRANSFER
NUCLEAR DEFORMATION
NUCLEAR FRAGMENTS
NUCLEAR MODELS
NUCLEAR POTENTIAL
NUCLEAR REACTIONS
NUMERICAL DATA
PARTIAL WAVES
POTENTIALS
SPECTRA
STATISTICAL MODELS
TARGETS
TRANS 104 ELEMENTS
TRANSPLUTONIUM ELEMENTS
TRANSURANIUM ELEMENTS
URANIUM 238 TARGET