1 / 18

Fusion-Incomplete Fusion

Sez.-CT. GDR pre-equilibrium emission 40 Ca+ 48 Ca, 46 Ti at 25 MeV/A. S.Tudisco EPL 58 (5), 811(2003) M.Papa et al, PRC 68., 034606 (2003) F.Amorini et al PRC 69, 014608(2004). Fusion-Incomplete Fusion. Dissipative binary processes. Extra yield at 10 MeV.

beckyh
Télécharger la présentation

Fusion-Incomplete Fusion

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Sez.-CT GDR pre-equilibrium emission 40Ca+48Ca,46Ti at 25 MeV/A S.Tudisco EPL 58 (5), 811(2003) M.Papa et al, PRC 68., 034606 (2003) F.Amorini et al PRC 69, 014608(2004) Fusion-Incomplete Fusion Dissipative binary processes Extra yield at 10 MeV

  2. GDR pre-equilibrium emission 40Ca+48Ca,46Ti at 10 MeV/A M.Papa et al, submitted to PRC Dissipative binary processes study of kinematical coincidence

  3. Z=14-22 Elab<160 MeV 40Ca+46Ti 40Ca+46Ti γ-2f 40Ca+48Ca γ-1f

  4. CoMD calculations TKEL-angular and charge distrib. b-window→ pre-eq γ Yield

  5. Sez.-CT How we can generate the coherent contribution? A simple picture the “Molecular Dipole” The average ensemble in an harmonic mean field The initial conditions for the GDR mode At the contact D1≈D2 ≈0 n p N1/Z1≠N2/Z2 if If Y=0 NO coherent contribution

  6. Sez.-CT • Incoherent contribution • Collective • Microscopicincoherent Coherent contribution (ensemble average) Mean field approach Statistical models Fully N-body dynamical approach for 1000 fm/c

  7. Sez.-CT Υ-ray average multiplicity in Semi classical Approximation The Larmor formula Fourier Transform

  8. Sez.-CT b=0 fm E/A 25 MeV Langevin prediction for the total system • Prediction in the loc. Time equil. hypothesis • Prediction according to a full CoMD approach g~12 M.Papa et al, PRC 68(2003) 034606

  9. Sez.-CT We have also high energy bremsstrahlung contribution We have to study the local time spectral properties of the  yield • We need to define T at long time • We need to separate the • incoherent Microscopic contribution

  10. Sez.-CT High energy results Multifragmentation of the hot source

  11. Sez.-CT   50 MeV/A b=0 fm M.Papa et al, PRC 68(2003) 024612  obtained from the fit procedure Very small Coherent contribution or

  12. Something is changed in the fundamental properties of the formed hot sources…. Degree of collectivity-Degree of coherence as function of t

  13. A new observable related to the properties of the dipolar γ-ray emission in different reaction mechanisms has been measured - Φch represents the ratio between the average and fluctuating dynamics. For N-body approaches able to evaluate the two contributions in a self consistent way, this parameter should be rather robust with respect some model ansatz: semiclassical approximaton, occupation numbers……. - On the other hand and we can expect that Φch can depend on the dynamics (Forces) governing the equilibration Process. From the experiments 10 MeV/A Binary. proc. Фch(12MeV)=0.6±0.15 Фch(10 MeV)=0.3±0.07 25 MeV/A Inc. fusion.proc.

  14. c(0,tm) c(0,tf) ch(0,tf) Collectivity and Coherence for the total system limiting energy for the collective motion M.Papa et al, PRC 68(2003) 024612, Black: rather smooth behaviour 40Ca + 48Ca Central Collisions Red:it contains the Ambiguity related to the experimental selections of 1 equilibrated source *10 Green:high sensitivi ty, related to the natural time selection performed by the dynamic through memory effects.

  15. CoMD calculations TKEL-angular and charge distrib. b-window→ pre-eq γ Yield

  16. γ-Pre-equilibrium effects and “Isospin-Equlibration” M.Papa et al Sub. PRC Invariant with respect to secondary statistical emission processes

  17. Sez.-CT Conclusive remarks • An unified description of the pre-equilibrium phenomenon (fluctuating average dynamics) has been obtained throgh ComD calculations 2. • The fluctuation predicted by the model are in agreement with Cascade calculations at 25 MeV/A by using g≈12. • 2. φch rapidly change when the multifragmentation processes set in. (much more than φc) • 3. The pre-equilibrium extra-yield it is strictly related to the • isospin equilibration process throgh a quasy-resonant mechanisms.

More Related