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  • Symmetric and asymmetric te...
    Siwek-Wilczynska, K; Wilczynski, J; Leegte, HK; Siemssen, RH; Wilschut, HW; Grotowski, K; Panasiewicz, A; Sosin, Z; Wieloch, A

    Physical review. C, Nuclear physics 48, Številka: 1
    Journal Article

    Emission of alpha particles accompanying fusion-fission processes in the sup 40Ar +sup 232Th reaction at ital E(sup 40Ar) = 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 7times10sup minus20 s) and the motion during the descent to scission almost completely damped.