1. Interfacing the JQMD and JAM Nuclear Reaction Codes to Geant4 Stanford Linear Accelerator Center Koi, Tatsumi tkoi@slac.stanford.edu

2. Collaboration with K. Niita (RIST) Y. Nara (University of Arizona) M. Asai (SLAC) D. H. Wright (SLAC) T. Sasaki (SLAC/KEK) K. Amako (KEK)

3. Outline Introducing joint activity of SLAC, KEK and other institutes for interfacing Fortran code of JQMD and JAM to Geant4 - To satisfy the urgent requirements for the beam test simulation of GLAST experiment. Contents What is JQMD What is JAM Interfacing Fortran reaction codes to Geant4 Demonstration Summary

4. We connected Fortran nuclear reaction codes to Geant4 which is written in C++. Advantages of this method are There are already many well-established reaction codes and these codes are often written in Fortran. It is more convenient interfacing to Fortran code directly than re-writing the code in C++. In the process of re-writing, new bugs may enter into the code. We can avoid this situation. Once the interface is established, the Fortran code and Geant4 can be updated independently. No copyright problems associated with re-writes.

5. At the first stage of this activity we chose two reaction codes, which satisfy our requirement (Nucleus-Nucleus Reactions) Jaeri Quantum Molecular Dynamics (JQMD) and Jet AA Microscopic Transport Model (JAM)

6. JQMD QMD (Quantum Molecular Dynamics) is quantum extension of classical molecular- dynamics model. QMD model is widely used to analyze various aspects of heavy ion reactions. JQMD ( Jaeri QMD) is a QMD code developed by JAERI ( Japan Atomic Energy Research Institute). JQMD includes SDM (Statistical Decay Model), SDM is used for evaporation and fission decays of excited nuclei.

7. JQMD (cont.) Energy Range of JQMD several 10 MeV/N up to about 3 GeV/N Projectile particle species nuclei (including protons and neutrons) and pions Detailed description of JQMD is given in Niita et al., Physical Review C 52 (1995) 2620 JQMD is also run within PHITS (Particle and Heavy-Ion Transport code System). Iwase et al., Journal of Nuclear Science and Technology 39 (2002) 1142

8. JAM JAM ( Jet AA Microscopic Transportation Model ) is a hadronic cascade model. The trajectories of all hadrons as well as resonances including produced particles are followed explicitly as a function of space and time. The inelastic hadron-hadron collisions are described by resonance formation and decay at low energies (below ~4GeV). Above 4GeV string formation and fragmentation into hadrons is assumed. Multiple minijet production is also included at high energies in the same way as the HIJING (Heavy Ion Jet INteraction Generator)

9. JAM (cont.) Energy Range of JAM several 100 MeV/N up to about 100 GeV/N and valid for many reactions at LHC and RHIC energies Projectile particle species nuclei (including protons and neutrons) mesons pions and kaons Detailed description of JAM is given in Nara et al., Physical Review C 561 (1999) 4901

10. In order to use JQMD and JAM from Geant4, we had to make interfaces. Before discussing interfaces, it is useful to review Geant4 processes and how they handle hadronic interactions.

11. What Does a Process Do in Geant4 Decides when and where an interaction will occur (GetPhysicalInteractionLength) Cross section Generates the final state (DoIt) Reaction model

12. What Does a Process Do in Geant4 (cont.) Process GetCrossSection() DoIt() Model ApplyYoursel() Cross Section When and where an interaction will occur? What will be generated by this interaction?

13. Hadron inelastic models ApplyYourself() JQMD2G4InelasticModel::ApplyYourself() or JAM2G4InelasticModel ::ApplyYourself() In this function, Fortran JQMD or JAM routine is called.

14. G4HadronicProcess GetCrossSection() PostStepDoIt() G4HadronicDiscreteProcess GetCrossSection() PostStepDoIt() G4HadronicInteracton ApplyYourSelf() JQMD2G4InelasticModel ApplyYourSelf() Fortran JQMD routine CrossSection G4Triphathi JQMD2G4Shen etc Framework of Hadron Interactions in Geant4 JAM2G4InelasticModel ApplyYourSelf() Fortran JAM routine

15. Cross Section for heavy ions GetCrossSection() Triphathi Formula NASA Technical Paper 3621 (1997) G4TriphathiCrossSection Shen Formula Nuclear Physics. A 491 (1989) 130 JQMD2G4ShenCrossSection

16. Platforms used Tested system OS: Red Hat Linux 7.2 (6.2) Compiler: gcc-2.95.3 (2.91.66 with egcs-1.1.2) Geant4: Ver. 5.0.p01 (2003 Feb version.) Demonstration System Cygwin 1.3.22-1 with gcc 3.2.3 We did not test this interface on other OS and compilers. Perhaps small modifications will be required.

17. Demonstrations N03HJQMD Based on Geant4 novice exampleN03 N03HJAM Based on Geant4 novice exampleN03 ICRU Sphere International Commission on Radiation Units Heavy ion passage in the tissue equivalent material

18. Simulation snapshot 1

19. Simulation snapshot 2

20. Simulation snapshot 3

21. Pion Plus from 17.5 GeV/c Proton on Be I. Chemakin et al., Phys. Rev. C 65, 4904 (2002) cos(θ)=0.75 cos(θ)=0.95 cos(θ)=0.65 cos(θ)=0.85

22. Pion from nucleus-nucleus interactions Sugaya et al., Nucl. Phys. A634, 115 (1998)

23. Pion from nucleus-nucleus interaction Papp, LBL-3633, (1975)

24. Conclusions We successfully developed the interface which connect JQMD and JAM to Geant4. Hadronic framework of Geant4 proved its flexibility and expandability. With this interface, we can simulate propagation of heavy ions in complex Geant4 geometries. Preliminary test results agree well with data. Much more validation to be done.