Evidence for quasifission in the sub-barrier reaction of {sup 30}Si+{sup 238}U

Journal Article · Fri Oct 15 04:00:00 EDT 2010 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.82.044604· OSTI ID:21419614

Nishio, K; Ikezoe, H; Nishinaka, I; Mitsuoka, S ^[1]; Hirose, K; Ohtsuki, T ^[2]; Watanabe, Y ^[3]; Aritomo, Y ^[1]; Hofmann, S ^[4]

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1. Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan)
2. Laboratory of Nuclear Science, Tohoku University, Sendai 982-0826 (Japan)
3. High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan)
4. GSI Helmholtzzentrum fuer Schwerionenforschung, D-64291 Darmstadt (Germany)

Fragment mass distributions for fission after full momentum transfer were measured for the {sup 30}Si+{sup 238}U reaction at bombarding energies around the Coulomb barrier. At energies above the Bass barrier, the mass distributions were Gaussian with mass symmetry. An asymmetric fission channel with mass A{sub L}/A{sub H} {approx_equal} 90/178 emerged at the sub-barrier energies, where competition between fusion and quasifission was suggested from the evaporation residue (ER) cross section produced in the fusion {sup 30}Si+{sup 238}U. We thus conclude the asymmetric channel is attributed to quasifission. It was supported by a model calculation using the Langevin equation to give the fragment mass distribution, where fusion-fission and quasifission were separated. The observed mass asymmetry for quasifission as well as the calculation is significantly smaller than those observed in actinide targets bombarded with heavier projectiles, which suggests that the system {sup 30}Si+{sup 238}U approaches the shape of the compound nucleus before disintegrating as quasifission.

• OSTI ID: 21419614
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 4 Vol. 82; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
ASYMMETRY
COMPOUND NUCLEI
COULOMB FIELD
CROSS SECTIONS
DISTRIBUTION
ELECTRIC FIELDS
EQUATIONS
EVEN-EVEN NUCLEI
FISSION
HEAVY ION REACTIONS
HEAVY NUCLEI
ISOTOPES
LANGEVIN EQUATION
LIGHT NUCLEI
MASS
MASS DISTRIBUTION
MOMENTUM TRANSFER
NUCLEAR FRAGMENTS
NUCLEAR REACTIONS
NUCLEI
QUASI-FISSION
RADIOISOTOPES
SHAPE
SILICON 30
SILICON ISOTOPES
SPATIAL DISTRIBUTION
SPONTANEOUS FISSION RADIOISOTOPES
STABLE ISOTOPES
SYMMETRY
URANIUM 238
URANIUM ISOTOPES
YEARS LIVING RADIOISOTOPES