Search for dynamical effects in the fission decay in the 240 MeV reactionG. La Rana1, A. Brondi1, R. Moro1, E. Vardaci1, A. Ordine1, A. Boiano1, M.A. Di Meo1, A. Scherillo1, D. Fabris2, M. Lunardon2, G. Nebbia2, G. Viesti2, M. Cinausero3, E. Fioretto3, G. Prete3, N. Gelli4 and F. Lucarelli4
1 Dipartimento di Scienze Fisiche, Università di Napoli "Federico II" and Istituto Nazionale di Fisica Nucleare, Via Cinthia, 80126 Napoli, Italy
2 Dipartimento di Fisica and Istituto Nazionale di Fisica Nucleare, Padova, Italy
3 Laboratori Nazionali di Legnaro dell' Istituto Nazionale di Fisica Nucleare, Legnaro (Padova), Italy
4 Dipartimento di Fisica and Istituto Nazionale di Fisica Nucleare, Firenze, Italy
(Received: 6 August 2002 / Published online: 4 February 2003)
Light particles in coincidence with evaporation residues and heavy fragments have been measured by a 4 charged-particle detector at the INFN Laboratori Nazionali di Legnaro (Padua) for the 240 MeV 32S + 100Mo reaction leading to the 132Ce composite system at 152 MeV of excitation energy. Energy spectra of the alpha-particles in coincidence with fission fragments were extracted for many correlation angles both in plane and out of plane. A prominent out-of-plane emission was observed, consistent with the pattern for the near-scission emission. From the fit to the spectra, the pre-scission alpha-particle multiplicity of was obtained. This value is reproduced by the code PACE2 without the inclusion of a delay time for fission. The presence of fast fission, which could be responsible for this result, is discussed.
25.70.Jj - Fusion and fusion-fission reactions.
© Società Italiana di Fisica, Springer-Verlag 2003