Mass asymmetry dependence of scission times in the reactions of 18. 5[ital A] MeV [sup 136]Xe+[sup 48]Ti

Journal Article · Fri Oct 01 04:00:00 EDT 1993 · Physical Review, C (Nuclear Physics); (United States)

DOI:https://doi.org/10.1103/PhysRevC.48.1791· OSTI ID:6195442

Gui, M; Hagel, K; Wada, R; Lou, Y; Utley, D; Xiao, B; Li, J; Natowitz, J B ^[1]; Enders, G; Kuehn, W; Metag, V; Novotny, R; Schwalb, O ^[2]; Charity, R J; Freifelder, R; Gobbi, A; Henning, W; Hildenbrand, K D; Mayer, R; Simon, R S ; Wessels, J P ^[3]; Casini, G; Olmi, A; Stefanini, A A ^[4]

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1. Cyclotron Institute, Texas A M University, College Station, Texas 77843 (United States)
2. II Physikalisches Instituet, Universtaet Giessen, D-6300 Giessen (Germany)
3. Gesellschaft fuer Schwerionenfurschung, Planck Strasse 1, D-6100 Darmstadt (Germany)
4. Universita di Firenze and Istituto Nazionale di Fisica Nucleare, Florence (Italy)

The multiplicities of [ital p] and [alpha] particles detected in coincidence with fragments emitted in fully relaxed collisions in the reactions of 18.5[ital A] MeV [sup 136]Xe+[sup 48]Ti have been measured for different exit channel mass asymmetries. A kinematic source analysis of the spectra and angular distributions of the light particles has been used to separate the total multiplicities into prescission and postscission contributions. From these results, the excitation energies at scission are determined using an empirical technique based upon previous measurements of light charged particle multiplicities observed in coincidence with evaporation residues. These excitation energies are found to decrease from [similar to]400 MeV to 110 MeV as the fragment mass asymmetry, [ital A][sub [ital H]]/[ital A][sub [ital L]], varies from 4.8 to 1.0. A corresponding increase of the mean lifetime of the scissioning nucleus from [similar to]5[times]10[sup [minus]22] s to [similar to]1[times]10[sup [minus]20] s is derived using calculated statistical model decay widths. The extent to which this variation of lifetime with mass asymmetry may be attributed to completely damped deep inelastic collisions or to dynamic delays in the decay of a compound nucleus is discussed as is the need for inclusion of dynamics in the deexcitation calculations for hot nuclei. Observed three fragment events are also discussed.

• OSTI ID: 6195442
• Journal Information: Physical Review, C (Nuclear Physics); (United States), Journal Name: Physical Review, C (Nuclear Physics); (United States) Vol. 48:4; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

663450* -- Heavy-Ion-Induced Reactions & Scattering-- (1992-)
663540 -- Nuclear Mass Ranges-- A=39-58-- (1992-)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALPHA PARTICLES
ANGULAR DISTRIBUTION
ASYMMETRY
BARYONS
CHARGED PARTICLES
CHARGED-PARTICLE REACTIONS
COMPOUND NUCLEI
DISTRIBUTION
ELEMENTARY PARTICLES
ENERGY SPECTRA
FERMIONS
HADRONS
HEAVY ION REACTIONS
LIFETIME
MASS
MULTIPLICITY
NUCLEAR REACTIONS
NUCLEONS
PROTONS
SPECTRA
TARGETS
TITANIUM 48 TARGET
XENON 136 REACTIONS