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Collective modes associated with the proton-induced fission of Bi209

par Nowicki, Lech;Borderie, Bernard;Cabot, C.;Tamain, Bernard;Berlanger, Michel ;Hanappe, Francis ;Del Marmol, P.;Grégoire, Claire ;El Masri, Youssef;Ngô, Christian
Référence Physical review. C. Nuclear physics, 26, 3, page (1114-1122)
Publication Publié, 1982

Article révisé par les pairs

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Résumé :

Gamma-ray multiplicity (first and second moments) has been measured in the 60 MeV proton-induced fission of Bi209. From this work we have evidence that shell effects play an effective role at the scission point, even at an excitation energy of 65 MeV. Collective modes seem to be more easily excited when the nascent fragments are far from spherical shapes. The γ-multiplicity moments seem to depend weakly on excitation energy of the fissioning nucleus and do not really reflect the angular momentum of the entrance channel. The good agreement of our results with the Moretto-Schmitt model highly supports the role played by collective modes (bending) in the heavy ion induced fission and deep inelastic collisions which are presently the field of many recent experimental and theoretical investigations. NUCLEAR REACTIONS p+Bi209; Ep=60 MeV; measured fission fragment mass distribution dNdM; measured γ-ray multiplicity first and second moments Mγ and σγ functions of fragment mass ratios α and ETKE;; measured average γ-ray energy Eγ (α); measured in-plane, out-of-plane Mγα(θ); comparison to s.f. and HI reaction mechanisms and to Moretto-Schmitt model; deduced effects of collective rotational modes (bending) on fragment spins. © 1982 The American Physical Society.