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A Pathway to a Transport Model for RAON

A Pathway to a Transport Model for RAON. Kyungil Kim. Dec. 7 th ,2013 ,HIM. Contents. RAON and Nuclear Reactions Introduction to Transport Model Equation of State and Symmetry Energy Transport Model for RAON Summary and Outlook. RAON and Nuclear Reactions.

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A Pathway to a Transport Model for RAON

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  1. A Pathway to a Transport Model for RAON Kyungil Kim Dec. 7th ,2013 ,HIM

  2. Contents • RAON and Nuclear Reactions • Introduction to Transport Model • Equation of State and Symmetry Energy • Transport Model for RAON • Summary and Outlook

  3. RAON and Nuclear Reactions • High intensity RI beams by ISOL & IF • ISOL : direct fission of 238U by p 70MeV • IF by 200MeV/u, 8.3pμA 238U • High quality neutron-richRI beams • 132Sn with up to ~250MeV/u, up to 107 • pps • Moreexotic RI beams by ISOL+IF Slide from Y.K.Kim’s presentation

  4. RAON and Nuclear Reactions figure from Y.K.Kim’s presentation

  5. RAON and Nuclear Reactions Fusion Induced fission Projectile Quasi fission Coulomb excitation Target Inelastic scattering Production of hadrons Multi- fragmentaion

  6. RAON and Nuclear Reactions DirectReactions Compound NuclearReactions Time ~10-20 sec ~10-16 sec Equilibrated (decay statistically) Non-equilibrium aspects p n α Low and intermediate energy regime : ~ 100 MeV/n - fusion, quasi-fission (multinucleon transfer) , fragmentation Relativistic regime : 100 MeV/n ~ a few GeV/n - production of hadrons, collective flow phenomena

  7. Transport Model? Transport model : Model to treat non-equilibrium aspects of the temporal evolution of a collision. • Many-body problem with nucleons • Numerical simulation • Direct reaction regime (compound nuclear reaction -> statistical model) • Different methods with different energies

  8. Various Codes • Boltzmann : Collision term • Uehling & Uhlenbeck, Nordheim : Pauli blocking • Vlasov : Mean field w/o collision • Landau : Averaged collisions • Many names, • Boltzmann-Uehling-Uhlenbeck : BUU • BNL , VUU, LV, … • Isospin dependent BUU : IBUU • Relativistic BUU : RBUU • … BUU Type Transport Model • Classical Molecular Dynamics : CMD • Quantum Molecular Dynamics : QMD • Antisymmetrized MD : AMD • Fermionic MD : FMD • Constrained MD : CoMD • Improved QMD : ImQMD • Ultra-relativistic QMD : UrQMD • … QMD Type

  9. Introduction to Transport Model 1. Initialization <Phase Space Density and Wigner Transforamtion> • Both a position and a momentum of nucleons are needed. • Phase space density!! • Wigner transformation

  10. Introduction to Transport Model • BUU Model • Semi-classical approach : point particles • Test particle method : 1~500 test particles per nucleon Randomly distributed ! • QMD Model • Gaussian wave packets L=1.08 fm2 -> rN=1.8 fm

  11. Introduction to Transport Model 2. Propagation 1 fm Boltzmann-Uehling-Uhlenbeck equation 1 fm drift term accelerating term collision term cf) RBUU eq. : • BUU Model Equation of motion Density dependent mean field (Unit box for density estimation)

  12. Introduction to Transport Model • QMD Model Equation of motion Nucleon-Nucleon interaction : Skyrme , Volkov , Gogny , … ex) Skyrme force ex) Gogny force

  13. Introduction to Transport Model 3. Collision Interaction radius = π(r1 + r2)2 r1 r2 Scatter with probability 1 ! Pauli blocking factor In-medium cross-section <Elastic and In-elastic scattering> NN -> NN , NN -> NΛK , NN -> NΔ , NΔ -> NΔ , Δ -> Nπ , …

  14. Introduction to Transport Model • BUU Model <Full ensemble method> <Parallel ensemble method> σTP= σNN/NTP NTP ensembles ~(ANTP)2 ~NTPA2

  15. Introduction to Transport Model 4. Clustering Identifications of collision fragments are performed by clustering nearby nucleons. Projectile A few MeV/n Fusion Target

  16. Introduction to Transport Model Initialization Propagation Collision Clustering More possible collisions? Yes No Particle identification

  17. EOS and Symmetry Energy Equation of State where, • Astrophysics (super novae, neutron star) • Giant monopole resonance • Heavy-ion collisions Ref.) A.Steiner et al. P.Rept 411 (2005) 325 Incompressibility of symmetry nuclear matter at its saturation density from Giant Monopole Resonance

  18. EOS and Symmetry Energy <The multifaceted influence of the nuclear symmetry energy> To explore the EOS of isospin asymmetric matter from heavy-ion reactions induced by neutron-rich beams, we need appropriate theoretical tools. -> Transport Model !! Ref.) A.Steiner et al. P.Rept 411 (2005) 325

  19. CoMD and ImQMD Typical QMD + constraints -> less CPU time Constrained Molecular Dynamics (CoMD) Restriction on phase space density Improved Quantum Molecular Dynamics (ImQMD) Consideration of surface energy

  20. CoMD and ImQMD Testing stability of nuclei Fusion cross-sections • N.Wang – Phys.Rev.C 65 (2002) 064608

  21. FMD and AMD Fermionic Molecular Dynamics (FMD) Antisymmetrized Molecular Dynamics (AMD) AMD wave function Slater Determinant Ex.) 12C in AMD Equation of motion for the wave packet centroids Z 3α structure Better fermionic nature -> more CPU time!

  22. FMD and AMD The charge distribution of the produced clusters in 129Xe+Sn at 50 MeV/n <Binding energies of nuclei> • A.Ono – Prog.Part.Nucl.Phys 53 (2004) 501

  23. Transport Model for RAON e.g. 11Li is bigger than 208Pb Unstable nuclei Nuclear Structure !!

  24. Transport Codes and Super Computer Cluster at RISP : 480 CPU cores Tachyon II at KISTI : 25408 CPU cores

  25. Summary and Outlook • RAON facility will provide opportunities to study isospin asymmetric matters and exotic nuclei by heavy-ion collisions induced by neutron-rich beams. • As a reliable theoretical tools, we need a transport model. • Transport model is a model to treat non-equilibrium aspects of the temporal evolution of a collision. • Many transport model codes are developed for different energy regions and observables. • To simulate HIC at RAON, we need a transport model which describes well low energy reactions and nuclear structures.

  26. References • BUU • G.Bertsch – Phys.Rept 160 (1988) 189 • P.Danielewicz – Ann.Phys 152 (1984) 239, 305 • RBUU • O.Buss – Phys.Rept 512 (2012) 1 • QMD • J.Aichelin – Phys.Rept 202 (1991) 233 • AMD • A.Ono – Prog.Part.Nucl.Phys 53 (2004) 501 • FMD • H.Feldmeier – Nucl.Phys A515 (1990) 147 • ImQMD • N.Wang – Phys.Rev.C 65 (2002) 064608 • CoMD • M.Papa – Phys.Rev.C 64 (2001) 024612

  27. Thank you for your attention!!

  28. Backup Slides

  29. <SchematicView of the Fusion Process> Inelastic b>bc scattering Projectile Quasi-fission 0<L<Lcap A few MeV/n Target Captureb<bc Compound Nucleus Fast-fission LB<L<Lcap Fission (Fusion-fission) Competition! p n Compound Nucleus Evaporation Fusion 0<L<LB α

  30. Super Heavy Elements at RAON

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