1. Maria Grazia Pia, INFN Genova and CERN1 Geant4 highlights of relevance for medical physics applications Maria Grazia Pia INFN Genova and CERN

2. Maria Grazia Pia, INFN Genova and CERN2 Geant4 features relevant for medical applications ] The transparency of physics ] Extensibility in any domain to satisfy new user requirements u thanks to OO technology (Open-Closed Principle) u open design: new physics, new features can be easily added, without any perturbation to the existing code ] Adopts standards wherever available (de jure or de facto) ] Use of evaluated data libraries ] Quality Assurance based on sound software engineering ] Subject to independent validation by a large user community worldwide ] User support organization by a large international Collaboration of experts

3. Maria Grazia Pia, INFN Genova and CERN3 A look at the past Physics simulation was handled through “packages” u monolithic: either take all of a package or nothing u difficult to understand the physics approach u hard to disentangle the data, their use and the physics modeling

4. Maria Grazia Pia, INFN Genova and CERN4 Transparency of Geant4 physics ] No “hard coded” numbers ] Explicit use of units throughout the code ] Separation between the calculation of cross sections and the generation of the final state ] Calculation of cross-sections independent from the way they are accessed (data files, analytical formulae etc.) ] Distinction between processes and models ] Cuts in range (rather than in energy, as usual) u consistent treatment of interactions near boundaries between materials ] Modular design, at a fine granularity, to expose the physics u physics independent from tracking ] Public distribution of the code, from one reference repository worldwide

5. Maria Grazia Pia, INFN Genova and CERN5 Physics processes relevant for medical applications ] Low Energy extensions of electromagnetic interactions u 250 eV electrons, photons u ~ 1 keV positive hadrons, ions u ICRU-compliant and ICRU-consistent u Barkas effect taken into account for antiprotons, negative ions u further extensions and refinements in progress ] Radioactive Decay Module u simulation of radioactive sources, including all the secondary emissions ] Multiple scattering u new improved model, taking into account also lateral displacement ] Hadronic interactions u ample variety of complementary and alternative models ] Neutrons u exploiting all the evaluated n data libraries worldwide

6. Maria Grazia Pia, INFN Genova and CERN6 Other features relevant for medical applications ] Powerful tools relevant for complex geometries (CT) u “smart voxels” u fast algorithms for volume navigation performance u volumes can be parameterised by material ] Fast and full simulation in the same environment u detailed handling of physics processes or possibility of parameterisations for faster processing ] Visualisation tools u wide variety functionalities available for all the most common drivers ] UI and GUI u user-friendly environement u can be easily tailored according to the user’s needs u GGE and GPE for automatic code generation +Ample documentation available from the web

7. Maria Grazia Pia, INFN Genova and CERN7 The Geant4 Collaboration ] An international Collaboration of ~100 scientists from >40 institutes u wide expertise in a variety of physics and software domains ] Manages Geant4 distribution, development and User Support u CERN, KEK, SLAC, TRIUMF, JNL (Common) u ESA, INFN +TERA, Lebedev, IN2P3, Frankfurt Univ. u Atlas, BaBar, CMS, LHCB u COMMON (Serpukov, Novosibirsk, US universities etc.) u possible new memberships under discussion ] Based on a Memorandum of Understanding among the parties

8. Maria Grazia Pia, INFN Genova and CERN8 User support ] Wide international user community, in a variety of fields of application u HEP and nuclear physics, astrophysics, space sciences, shielding and radioprotection, medical physics, theoretical physics, fine arts etc. ] Effective model of user support u granular organisation u provided by a wide network of experts, each one in its domain of expertise u automatic tools for bug notifications u consultancy, requests of enhancements and new developments etc. u priority given to member parties