Pre-scission sup 4 He multiplicity in the sup 19 F+ sup 197 Au reaction

Journal Article · Sun Jul 01 04:00:00 EDT 1990 · Physical Review, C (Nuclear Physics); (USA)

DOI:https://doi.org/10.1103/PhysRevC.42.342· OSTI ID:6504933

Ikezoe, H; Shikazono, N; Nagame, Y; Sugiyama, Y; Tomita, Y; Ideno, K; Iwamoto, A ^[1]; Ohtsuki, T ^[2]

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1. Department of Physics, Japan Atomic Energy Research Institute, Tokai-mura, Ibaraki-ken (Japan)
2. Department of Chemistry, Faculty of Science, Tokyo Metropolitan University, Setagaya-ku, Tokyo (Japan)

Pre- and post-scission {sup 4}He particle multiplicities for the {sup 19}F+{sup 197}Au reaction in the excitation energy range of 43 to 90 MeV have been measured in coincidence with fission fragments. The coincident {sup 4}He particles measured at backward angles are accounted for by evaporation from a compound nucleus and fission fragments. The most probable center-of-mass energy of the {sup 4}He particles measured at backward angles is shifted towards lower energies by {approx}2 MeV compared to a statistical model calculation performed by assuming {sup 4}He emission from a spherical compound nucleus. The observed pre-scission {sup 4}He multiplicity as a function of excitation energy is compared to a set of statistical-model calculations which also included the delayed onset of fission. The comparison shows that the observed energy dependence of the pre-scission {sup 4}He multiplicity is reproduced by the calculation without taking into account the delayed onset of fission if the reduced emission barrier for {sup 4}He is assumed in the calculation. The emission mechanism of the pre-scission {sup 4}He is discussed.

• OSTI ID: 6504933
• Journal Information: Physical Review, C (Nuclear Physics); (USA), Journal Name: Physical Review, C (Nuclear Physics); (USA) Vol. 42:1; ISSN 0556-2813; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

651320 -- Nuclear Properties & Reactions
A=6-19
Experimental
651920* -- Nuclear Properties & Reactions
A=190-219
Experimental
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACCELERATORS
ANGULAR DISTRIBUTION
CHARGED-PARTICLE REACTIONS
COINCIDENCE SPECTROMETRY
COMPOUND-NUCLEUS REACTIONS
DISTRIBUTION
ELECTROSTATIC ACCELERATORS
EMISSION
ENERGY SPECTRA
EVAPORATION MODEL
EVEN-EVEN NUCLEI
FISSION
FISSION FRAGMENTS
FLUORINE 19 REACTIONS
GOLD 197 TARGET
HEAVY ION REACTIONS
HELIUM 4
HELIUM ISOTOPES
ISOTOPES
JAERI TANDEM ACCELERATOR
LIGHT NUCLEI
MATHEMATICAL MODELS
NUCLEAR FRAGMENTS
NUCLEAR MODELS
NUCLEAR REACTIONS
NUCLEI
SPECTRA
STABLE ISOTOPES
STATISTICAL MODELS
TANDEM ELECTROSTATIC ACCELERATORS
TARGETS