1. Status of Photon Evaporation Alessandro Brunengo INFN Genova Alessandro Brunengo Geant4 Workshop at Noordwijk, The Netherlands 20-24 September 1999

2. Alessandro BrunengoGeant4 Workshop at Noordwijk, The Netherlands 20-24 September 1999 Contributors Alessandro Brunengo - INFN Genova Alessandro.Brunengo@ge.infn.it Carlo Dallapiccola - University of Maryland dallapiccola@umdhep.umd.edu Maria Grazia Pia - INFN Genova Maria.Grazia.Pia@ge.infn.it

3. Alessandro BrunengoGeant4 Workshop at Noordwijk, The Netherlands 20-24 September 1999 Photon Evaporation It is one of possible de-excitation channels for excited nuclei. Two qualitative different kind of events: Ý Continuum γ energy distribution Evaporation channel in competition with the others (evaporation, fission, Fermi break-up, multifragmentation). Ý Discrete energy transitions Last step of evaporation cascade, at low excitation energy.

4. Alessandro BrunengoGeant4 Workshop at Noordwijk, The Netherlands 20-24 September 1999 Continuum γ energies It is part of the theory driven model. Ý E1 γ transitions only Ý Emitted γ energies sampled according to the distribution for Giant Dipole Resonance Ý Energy and width of GDR are independent from the nucleus excitation energy

5. Alessandro BrunengoGeant4 Workshop at Noordwijk, The Netherlands 20-24 September 1999 Discrete γ energies No other de-excitation channels at these energy levels ENSDF experimental data used for all de- excitation parameters: Ý nuclear level energy, angular momentum, half life Ý emitted γ energy, polarity, relative probability of emission from a given level

6. Photon Evaporation Design

7. Alessandro BrunengoGeant4 Workshop at Noordwijk, The Netherlands 20-24 September 1999 Photon energy, discrete levels Sn(120), 80 MeV Sn(112), 80 MeV MeV

8. Alessandro BrunengoGeant4 Workshop at Noordwijk, The Netherlands 20-24 September 1999 Photon creation time, discrete levels Sn(112): level at 2.51 MeV  (exp)  1.4·10 -12 sec  (fit)  1.3·10 -12 sec

9. Alessandro BrunengoGeant4 Workshop at Noordwijk, The Netherlands 20-24 September 1999 Gamma energy, continuum Sn(120) 80 MeV GDR Sn(112) 80 MeV MeV

10. Alessandro BrunengoGeant4 Workshop at Noordwijk, The Netherlands 20-24 September 1999 Photon creation time delay, continuum Sn(112) 80 MeVSn(120) 80 MeV

11. Alessandro BrunengoGeant4 Workshop at Noordwijk, The Netherlands 20-24 September 1999 Excitation energy at photon evaporation code activation Sn(112) 80 MeVSn(120) 80 MeV MeV

12. Alessandro BrunengoGeant4 Workshop at Noordwijk, The Netherlands 20-24 September 1999 To be done Angular distribution of photons Ý The complete knowledge of initial and final states of angular momentum is needed (e.g. transitions to a final state with J=0) ENSDF data Ý management of (infrequent) inconsistencies in experimental data Ý update from ENSDF

13. Alessandro BrunengoGeant4 Workshop at Noordwijk, The Netherlands 20-24 September 1999 Excitation energy at photon evaporation code activation Sn(112) 80 MeV Sn(120) 80 MeVSn(120) 100 MeV

14. Alessandro BrunengoGeant4 Workshop at Noordwijk, The Netherlands 20-24 September 1999 From Geant4 Gallery