1. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Architecture of collaborating frameworks Architecture of collaborating frameworks Simulation, Visualisation, User Interface and Analysis G. Cosmo, R. Giannitrapani, F. Longo, R. Nartallo, P. Nieminen, A. Pfeiffer, M.G. Pia, G. Santin CERN - ESA - INFN (Ferrara, Genova, Trieste) Budker Inst. of Physics IHEP Protvino MEPHI Moscow Pittsburg University CHEP 2001 Conference Beijing, 3-7 September 2001 http://www.ge.infn.it/geant4/lowE/index.html

2. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 UKDM, Boulby Mine GLAST Budker Inst. of Physics IHEP Protvino MEPHI Moscow Pittsburg University ATLAS BaBar A rigorous approach to software engineering Courtesy of L3 Courtesy of the Italian Nat. Inst. for Cancer Research E (MeV) Photon attenuation An extensive set of physics processes and models over a wide energy range High energy  Low energy photons  particle in a cell 192 Ir highlights highlights

3. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Geant4 is a simulation Toolkit designed for a variety of applications It adopts rigorous software engineering methodologies and is based on OO technology It has been developed and is maintained by an international collaboration of > 100 scientists -RD44 Collaboration (1994-98) -Geant4 Collaboration The code is publicly distributed from the WWW, together with ample documentation 1st production release: end 1998 -2 new releases/year since then It provides a complete set of tools for all the typical domains of simulation -run, event and track management -geometry and materials -tracking -detector response -PDG-compliant particle management -user interface -visualisation -persistency -physics processes A wide domain of applications with a large user community in many fields HEP, astrophysics, nuclear physics, space sciences, medical physics, radiation studies etc.

4. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Domain decomposition hierarchical structure of sub-domains Geant4 architecture Uni-directional flow of dependencies Software Engineering plays a fundamental role in Geant4 User Requirements formally collected systematically updated PSS-05 standard Software Process spiral iterative approach regular assessments and improvements monitored following the ISO 15504 model Quality Assurance commercial tools code inspections automatic checks of coding guidelines testing procedures at unit and integration level dedicated testing team Object Oriented methods OOAD use of CASE tools essential for distributed parallel development contribute to the transparency of physics Use of Standards de jure and de facto

5. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Geometry Borexino CMS ATLAS Chandra XMM- Newton Role: detailed detector description and efficient navigation CSG CSG (Constructed Solid Geometries) - simple solids STEP extensions - polyhedra,, spheres, cylinders, cones, toroids, etc. BREPS BREPS (Boundary REPresented Solids) - volumes defined by boundary surfaces - include solids defined by NURBS (Non-Uniform Rational B-Splines) External tool for g3tog4 geometry conversion Multiple representations (Same abstract interface) CAD exchange: ISO STEP interface Fields: of variable non-uniformity and differentiability BaBar

6. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Guidelines for physics From the Minutes of LCB (LHCC Computing Board) meeting on 21 October, 1997: Geant4 physics keeps evolving with attention to UR facilitated by the OO technology “It was noted that experiments have requirements for independent, alternative physics models. In Geant4 these models, differently from the concept of packages, allow the user to understand how the results are produced, and hence improve the physics validation. Geant4 is developed with a modular architecture and is the ideal framework where existing components are integrated and new models continue to be developed.”

7. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Geant4 Physics OOD allows to implement or modify any physics process without changing other parts of the software  open to extension and evolution Tracking Tracking is independent from the physics processes final state The generation of the final state is independent from the access and use of cross sections Transparent access via virtual functions to -cross sections -cross sections (formulae, data sets etc.) -models -models underlying physics processes electromagnetic hadronic An abundant set of electromagnetic and hadronic physics processes physics models  a variety of complementary and alternative physics models for most processes evaluated databases Use of public evaluated databases production thresholds No tracking cuts, only production thresholds range -thresholds for producing secondaries are expressed in range, universal for all media -converted into energy for each particle and material The transparency of the physics implementation contributes to the validation of experimental physics results

8. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Multiple scattering Bremsstrahlung Ionisation Annihilation Photoelectric effect Compton scattering Rayleigh effect  conversion e + e - pair production Synchrotron radiation Transition radiation Cherenkov Refraction Reflection Absorption Scintillation Fluorescence Auger (in progress) Electromagnetic physics High energy extensions -needed for LHC experiments, cosmic ray experiments… Low energy extensions -fundamental for space and medical applications,  experiments, antimatter spectroscopy etc. Alternative models for the same process energy loss  electrons and positrons , X-ray and optical photons muons n charged hadrons n ions Comparable to Geant3 already in the 1st  release (1997) Further extensions (facilitated by the OO technology) All obeying to the same abstract Process interface  transparent to tracking

9. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Standard e.m. processes Multiple scattering -new model (by L. Urbán) -computes mean free path length and lateral displacement New energy loss algorithm -optimises the generation of  rays near boundaries Variety of models Variety of models for ionisation and energy loss -including the PhotoAbsorption Interaction model Differential and Integral approach -for ionisation, Bremsstrahlung, positron annihilation, energy loss and multiple scattering Multiple scattering 6.56 MeV proton, 92.6 mm Si J.Vincour and P.Bem Nucl.Instr.Meth. 148. (1978) 399 1 keV up to O(100 TeV) Geant4 Geant3 data

10. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Low energy e.m. extensions e,  down to 250 eV (EGS4, ITS to 1 keV, Geant3 to 10 keV) Fundamental for neutrino/dark matter experiments, space and medical applications, antimatter spectroscopy etc. Hadron and ion models based on Ziegler and ICRU data and parameterisations Barkas effect (charge dependence) models for negative hadrons Based on EPDL97, EEDL and EADL evaluated data libraries Bragg peak shell effects Photon attenuation antiprotons protons ions

11. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Muons 1 keV up to 1000 PeV scale 1 keV up to 1000 PeV scale simulation of ultra-high energy and cosmic ray physics High energy extensions based on theoretical models Optical photons  Production of optical photons in HEP detectors is mainly due to Cherenkov effect and scintillation Processes in Geant4: Processes in Geant4: -in-flight absorption -Rayleigh scattering -medium-boundary interactions (reflection, refraction) Photon entering a light concentrator CTF-Borexino

12. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Parameterised and data-driven hadronic models (1) Based on experimental data Some models originally from GHEISHA -completely reengineered into OO design -refined physics parameterisations New parameterisations -pp, elastic differential cross section -nN, total cross section -pN, total cross section -np, elastic differential cross section  N, total cross section  N, coherent elastic scattering p elastic scattering on Hydrogen

13. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Other models are completely new, such as: Neutrons Courtesy of CMS nuclear deexcitation absorption Stopping  MeV Energy All worldwide existing databases used in neutron transport Brond, CENDL, EFF, ENDFB, JEF, JENDL, MENDL etc. neutrons stopping particles :  -, K - (relevant for  PID detectors) Isotope production Parameterised and data-driven hadronic models (2)

14. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Theory-driven models Giant Dipole Resonance Geant4 data Discrete transitions from ENSDF Theoretical model for continuum Evaporation phase Low energy range, pre-equilibrium, O(100 MeV) Intermediate energy range, O(100 MeV) to O(5 GeV), intra-nuclear transport High energy range, hadronic generator régime Complementary and alternative models

15. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Other components Materials -elements, isotopes, compounds, chemical formulae Particles -all PDG data -and more, for specific Geant4 use, like ions Hits & Digi -to describe detector response Persistency -possibility to run in transient or persistent mode -no dependence on any specific persistency model -persistency handled through abstract interfaces to ODBMS Visualisation -Various drivers -OpenGL, OpenInventor, X11, Postscript, DAWN, OPACS, VRML User Interfaces -Command-line, Tcl/Tk, Tcl/Java, batch+macros, OPACS, GAG, MOMO -automatic code generation for geometry and materials Interface to Event Generators -through ASCII file for generators supporting /HEPEVT/ -abstract interface to Lund++

16. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Sector Shielding Analysis Tool CAD tool front-end Delayed radioactivity General purpose source particle module INTEGRAL and other science missions Instrument design purposes Dose calculations Particle source and spectrum Geological surveys of asteroids Modules for space applications Modules for space applications Low-energy e.m. extensions Courtesy of P. Nieminen, ESA

17. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Courtesy of A. Pfeiffer, CERN Example: AIDA & Analysis Tools Similar approach: graphics (G)UI persistency etc. Interface to external tools  No dependence  Minimize coupling of components Java Analysis Studio Lizard Through abstract interfaces AIDA

18. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 BaBar Courtesy of D. Wright for the BaBar Collaboration Preliminary

19. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Example of integrated Fast/Full Simulation application B aBar O bject-oriented G eant4-based U nified S imulation (BOGUS) l Integrated framework for Fast and Full simulation l Fast simulation available for public use since February 1999 l Integrated in BaBar environment nprimary generators, reconstruction, OODB persistency nparameters for materials and geometry shared with reconstruction applications Courtesy of G. Cosmo for the BaBar Collaboration Exploits Geant4 parameterisation (new feature)

20. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 ATLAS 300 GeV muons 20 GeV pions TRT: Energy loss measured in ATLAS test beam compared to Geant3 and Geant4 simulations (PAI model) Liquid Ar calorimeter Fcal energy resolution Muon detector Preliminary Courtesy of D. Barberis for ATLAS Collaboration

21. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 HARP with GEANT4 Courtesy of P. Arce for the HARP Collaboration

22. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 T9 beam line Beam profile and composition at the HARP target Simulation (10 GeV/c)Measurement Beam spot width (mm)3.27approx. 4 Beam spot height (mm)3.49approx. 4 Beam spot position (mm)(0.33:0.86)(0.0:0.0) Sophisticated geometry Very non-uniform strong magnetic field Primary target as a particle source Courtesy of P. Arce for the HARP Collaboration Preliminary Crucial to have a precise absolute knowledge of the particle rate incident onto HARP target Impossible to separate experimentally  from  in the beam with the accuracy required

23. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 GLAST (  ray telescope) Preliminary Courtesy of F. Longo and R. Giannitrapani, GLAST GLAST

24. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Other astroparticle applications Courtesy of S. Magni, Borexino Courtesy of A. Howard, UKDM ZEPLIN III Dark Matter, Boulby mine Courtesy of R. Nartallo, ESA XMM X-ray telescope Courtesy SOHO EIT Cosmic rays, jovian electrons Solar X-rays, e, p low E physics fluorescence radioactivity neutrons space modules etc.. unique simulation capabilities: Solar system explorations

25. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Technology transfer Brachytherapy Courtesy National Inst. for Cancer Research, Genova Medical applications of Geant4: radiotherapy PET dosimetry etc. Treatment planning anisotropy Isodoses Courtesy LIP & Portuguese Oncological Institute Commercial treatment planning system data Histogram: Geant4 192 Ir

26. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Conclusions Geant4 is a simulation Toolkit, providing advanced tools for all the domains of detector simulation Geant4 is characterized by a rigorous approach to software engineering Thanks to the OO technology, Geant4 is open to extension and evolution An abundant set of physics processes is available, often with a variety of complementary and alternative physics models Its areas of application span diverse fields: HEP and nuclear physics, astrophysics and space sciences, medical physics, radiation studies etc.