1. Pete Truscott QinetiQ Space LoB
DPMJET-II.5 and DPMJET-III Implementation in Geant4 Overview & Status Report
Pete Truscott
QinetiQ Space LoB
03 July 2008

2. Implementation of DPMJET-II.5 model in Geant4 (1)
Existing FORTRAN code DPMJET-II.5 to act as an event generator:
5GeV/nuc to 1E+11 GeV/nuc
applicable to all projectiles & targets
Poorly documented code: no explanation of the design / organisation of the code; each subroutine having little (or often no) description; little explanation of internal variables/common blocks
Geant4 DPMJET-II.5 interface: G4DPMJET2_5Model class now developed and under test
After prompt nuclear-nuclear collisions, nuclear de-excitation treated using other Geant4 models (precompound, evaporation, Fermi break-up)
Default is precompound, but user can override and declare her own precompound, G4ExcitationHandler or no de-excitation.
DPMJET-II.5 FORTRAN code requires Glauber profile data: integral probability function used to sample impact parameter
For Geant4 implementation, determined as a function of AP and AT rather than (AP, ZP) and (AT, ZT)
Current version of database of Glauber profile data available applicable to projectiles from AP = 2 to AP = 58 on target nuclei with AT = 2 to AT = 58
It is hoped that this will be expanded in due course to projectiles up to A=240 and similarly for targets, but time for generating data extensive (it took ~10 CPU months for A=2 to A=58)

3. Implementation of DPMJET-II.5 model in Geant4 (2)
Total inelastic cross-sections
Total inelastic cross-section class G4DPMJET2_5CrossSection created to do this, and also covers projectiles from A=2 to A=58 on targets from A=2 to A=58 (by-product of DPMJET-II.5)
Some comparisons performed at the low-energy (~5GeV) end of the cross-section curve, but limited available data for total inelastic cross-sections at ultra-relativistic energies – does anyone know of any data?
S/W Compatibility
Tested with G4 v8.3 (tested at reference tag 0), v9.0 (patch 01), v9.1 (tested at reference tag 3) (so I have been told!) built with compiler versions:
gcc v3.2.3 with g77 v3.2.3
gcc v4.0.0 with g77 v3.2.3
gcc v4.2.0 with gfortran v4.2.0
gcc v4.2.3 with gfortran v4.2.3
WARNING: DPMJET-II.5 FORTRAN has problems with gfortran v4.0.0 and gfortran v4.1.0 (see software manual); it’s possible that latter will work with 32-bit machines.

4. Implementation of DPMJET-II.5 model in Geant4 (3)
Use in physics list
G4ExcitationHandler *theExcitationHandler = new G4ExcitationHandler;
G4Evaporation * theEvaporation = new G4Evaporation;
G4FermiBreakUp * theFermiBreakUp = new G4FermiBreakUp;
theExcitationHandler->SetEvaporation(theEvaporation);
theExcitationHandler->SetFermiModel(theFermiBreakUp);
theExcitationHandler->SetMaxAandZForFermiBreakUp(17, 9);
theDPM = new G4DPMJET2_5Model(DEFAULT);
theDPM->SetExcitationHandler(theExcitationHandler);
theDPM->SetMinEnergy(6*GeV);
theDPM->SetMaxEnergy(100*TeV);
Notes/other constraints:
Interactions of heavy ions on protons currently ignored (G4DPMJET2_5Model doesn’t currently treat protons)
QinetiQ has not included DPMJET-II.5 FORTRAN with release, but easy to download from Ranft’s web-site (see G4dpmjet2_5 software manual)
Scripts included with G4dpmjet2_5 to apply patch the DPMJET-II.5 FORTRAN source before compilation
Instructions in software manual on how to install & build G4dpmjet2_5, and modifications required to user’s GNUmakefile

5. Secondary proton energy spectra from A-A collisions G4dpmjet2_5 & FLUKA (1)

6. Secondary proton energy spectra from A-A collisions G4dpmjet2_5 & FLUKA (2)
G4dpmjet2_5 following DPMJET-III here?
Suggests at low-energy collisions, G4dpmjet2_5 over predicts (at least compared with FLUKA)?

7. Secondary proton &  rapidity spectra from A-A collisions G4dpmjet2_5 & experiment
Shows underprediction
Proton 

8. Status & future work
G4dpmjet2_5 showing good consistency at high collision energies, but discrepancies at lower energies (~10GeV/nuc)
No feedback yet on draft code … I’m not sure anyone has tried to use it
Functional and physics testing performed but more testing should be undertaken – critical to other MarsREM project deliverables
Need to discuss with, e.g. Gunter, how to implement in G4 release, and once this is sorted, commit source to repository
Proton-nuclear and nuclear-proton interactions
Already started DPMJET-III implementation (MarsREM)
Extend Glauber profile data and Glauber inelastic cross-section data beyond A=58

9. Backup Slides

10. G4dDPMJET2_5Model logical flow

11. Summary of G4DPMJET2_5Model classes

12. G4dDPMJET2_5CrossSection logical flow