Symmetric and asymmetric ternary fission of hot nuclei

Journal Article · Thu Jul 01 00:00:00 EDT 1993 · Physical Review, C (Nuclear Physics); (United States)

DOI:https://doi.org/10.1103/PhysRevC.48.228· OSTI ID:6329234

Siwek-Wilczynska, K ^[1]; Wilczynski, J ^[2]; Leegte, H K.W.; Siemssen, R H; Wilschut, H W ^[3]; Grotowski, K; Panasiewicz, A; Sosin, Z; Wieloch, A ^[4]

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1. Kernfysisch Versneller Instituut, 9747 AA Groningen (Netherlands) Institute of Experimental Physics, Warsaw University, 00-681 Warsaw (Poland)
2. Kernfysisch Versneller Instituut, 9747 AA Groningen (Netherlands) Soltan Institute for Nuclear Studies, 05-400 Swierk-Otwock (Poland)
3. Kernfysisch Versneller Instituut, 9747 AA Groningen (Netherlands)
4. Institute of Physics, Jagellonian University, 30-059 Cracow, Poland Institute of Nuclear Physics, 31-342 Cracow (Poland)

Emission of [alpha] particles accompanying fusion-fission processes in the [sup 40]Ar +[sup 232]Th reaction at [ital E]([sup 40]Ar) = 365 MeV was studied in a wide range of in-fission-plane and out-of-plane angles. The exact determination of the emission angles of both fission fragments combined with the time-of-flight measurements allowed us to reconstruct the complete kinematics of each ternary event. The coincident energy spectra of [alpha] particles were analyzed by using predictions of the energy spectra of the statistical code CASCADE . The analysis clearly demonstrates emission from the composite system prior to fission, emission from fully accelerated fragments after fission, and also emission during scission. The analysis is presented for both symmetric and asymmetric fission. The results have been analyzed using a time-dependent statistical decay code and confronted with dynamical calculations based on a classical one-body dissipation model. The observed near-scission emission is consistent with evaporation from a dinuclear system just before scission and evaporation from separated fragments just after scission. The analysis suggests that the time scale of fission of the hot composite systems is long (about 7[times]10[sup [minus]20] s) and the motion during the descent to scission almost completely damped.

• OSTI ID: 6329234
• Journal Information: Physical Review, C (Nuclear Physics); (United States), Vol. 48:1; ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ARGON 40 REACTIONS
HEAVY ION FUSION REACTIONS
THORIUM 232 TARGET
ALPHA PARTICLES
FISSION FRAGMENTS
MEV RANGE 100-1000
TERNARY FISSION
TIME-OF-FLIGHT SPECTROMETERS
CHARGED PARTICLES
CHARGED-PARTICLE REACTIONS
ENERGY RANGE
FISSION
HEAVY ION REACTIONS
MEASURING INSTRUMENTS
MEV RANGE
NUCLEAR FRAGMENTS
NUCLEAR REACTIONS
SPECTROMETERS
TARGETS
663470* - Fission- (1992-)
663450 - Heavy-Ion-Induced Reactions & Scattering- (1992-)
663590 - Nuclear Mass Ranges- A=220 & Above- (1992-)