Architecture of collaborating frameworks Simulation, Visualisation, User Interface and Analysis http://www.ge.infn.it/geant4/lowE/index.html G. Cosmo, R.
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Architecture of collaborating frameworks Simulation, Visualisation, User Interface and Analysis http://www.ge.infn.it/geant4/lowE/index.html G. Cosmo, R. Giannitrapani, F. Longo, R. Nartallo, P. Nieminen, A. Pfeiffer, M.G. Pia, G. Santin CERN - ESA - INFN (Ferrara, Genova, Trieste) CHEP 2001 Conference Beijing, 3-7 September 2001 Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Budker Inst. of Physics IHEP Protvino MEPHI Moscow Pittsburg University ATLAS BaBar highlights An extensive set of physics processes and models over a wide energy range Courtesy of L3 Photon attenuation Courtesy of the Italian Nat. Inst. for Cancer Research a particle in a cell Ir 192 UKDM, Boulby Mine E (MeV) High energy m Low energy photons A rigorous approach to software engineering Maria Grazia Pia, INFN Genova - EPS-HEP 2001 GLAST A wide domain of applications with a large user community in many fields 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 HEP, astrophysics, nuclear physics, space sciences, medical physics, radiation studies etc. 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 - RD44 Collaboration (1994-98) - PDG-compliant particle management - Geant4 Collaboration - user interface The code is publicly distributed from the WWW, together with ample documentation 1st production release: end 1998 - 2 new releases/year since then Maria Grazia Pia, INFN Genova - EPS-HEP 2001 - visualisation - persistency - physics processes Geant4 architecture Software Engineering plays a fundamental role in Geant4 Domain decomposition User Requirements • formally collected • systematically updated • PSS-05 standard Software Process hierarchical • spiral iterative approach structure of • regular assessments and improvements • monitored following the ISO 15504 model sub-domains • OOAD Object Oriented methods • use of CASE tools • essential for distributed parallel development Uni-directional flow of • contribute to the transparency of physics dependencies • commercial tools Quality Assurance • code inspections • automatic checks of coding guidelines • testing procedures at unit and integration level • dedicated testing team Use of Standards Maria Grazia Pia, INFN Genova - EPS-HEP 2001 • de jure and de facto Geometry Role: detailed detector description and efficient navigation Chandra ATLAS Multiple representations BaBar (Same abstract interface) CSG (Constructed Solid Geometries) - simple solids XMMNewton STEP extensions - polyhedra,, spheres, cylinders, cones, toroids, etc. BREPS (Boundary REPresented Solids) - volumes defined by boundary surfaces - include solids defined by NURBS (Non-Uniform Rational B-Splines) CAD exchange: ISO STEP interface Fields: of variable non-uniformity and differentiability Borexino External tool for g3tog4 geometry conversion Maria Grazia Pia, INFN Genova - EPS-HEP 2001 CMS Guidelines for physics From the Minutes of LCB (LHCC Computing Board) meeting on 21 October, 1997: “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.” Geant4 physics keeps evolving with attention to UR facilitated by the OO technology 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 is independent from the physics processes The generation of the final state is independent from the access and use of cross sections Transparent access via virtual functions to - cross sections (formulae, data sets etc.) - models underlying physics processes An abundant set of electromagnetic and hadronic physics processes a variety of complementary and alternative physics models for most processes Use of public evaluated databases No tracking cuts, only production thresholds - - 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 Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Electromagnetic physics energy loss electrons and positrons g, X-ray and optical photons muons charged hadrons ions Comparable to Geant3 already in the 1st a release (1997) Further extensions (facilitated by the OO technology) Multiple scattering Bremsstrahlung Ionisation Annihilation Photoelectric effect Compton scattering Rayleigh effect g conversion e+e- pair production Synchrotron radiation Transition radiation Cherenkov Refraction Reflection Absorption Scintillation Fluorescence Auger (in progress) High energy extensions - needed for LHC experiments, cosmic ray experiments… Low energy extensions - fundamental for space and medical applications, n experiments, antimatter spectroscopy etc. Alternative models for the same process All obeying to the same abstract Process interface transparent to tracking Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Standard e.m. processes 1 keV up to O(100 TeV) Multiple scattering - new model (by L. Urbán) - computes mean free path length and lateral displacement New energy loss algorithm - optimises the generation of d rays near boundaries Multiple scattering 6.56 MeV proton , 92.6 mm Si Geant4 Geant3 data 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 J.Vincour and P.Bem Nucl.Instr.Meth. 148. (1978) 399 Maria Grazia Pia, INFN Genova - EPS-HEP 2001 shell effects Low energy e.m. extensions Fundamental for neutrino/dark matter experiments, space and medical applications, antimatter spectroscopy etc. e,g down to 250 eV (EGS4, ITS to 1 keV, Geant3 to 10 keV) Based on EPDL97, EEDL and EADL evaluated data libraries Geant4 LowEn NIST 1000 m /r (cm 2 /g) in iron Barkas effect (charge dependence) models for negative hadrons Photon attenuation 100 protons 10 1 antiprotons 0.1 0.01 0.01 0.1 1 10 Maria Grazia Pia,Photon INFNEnergy Genova (MeV) - EPS-HEP 2001 Bragg peak Hadron and ion models based on Ziegler and ICRU data and parameterisations ions Muons Optical photons 1 keV up to 1000 PeV scale Production of optical photons in HEP detectors is mainly due to Cherenkov effect and scintillation simulation of ultra-high energy and cosmic ray physics High energy extensions based on theoretical models Processes in Geant4: - in-flight absorption Rayleigh scattering medium-boundary interactions (reflection, refraction) Photon entering a light concentrator CTF-Borexino 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 Maria Grazia Pia, INFN Genova - EPS-HEP 2001 p elastic scattering on Hydrogen Parameterised and data-driven hadronic models (2) Other models are completely new, such as: Stopping stopping particles: - , K- (relevant for m/ PID detectors) absorption Isotope production nuclear deexcitation neutrons MeV Neutrons Courtesy of CMS Energy All worldwide existing databases used in neutron transport Brond, CENDL, EFF, ENDFB, JEF, JENDL, MENDL etc. Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Theory-driven models Complementary and alternative models Discrete transitions from ENSDF data Geant4 Theoretical model for continuum Giant Dipole Resonance 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 Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Other components Materials - elements, isotopes, compounds, chemical formulae Visualisation - Particles - all PDG data and more, for specific Geant4 use, like ions User Interfaces - 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 Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Various drivers OpenGL, OpenInventor, X11, Postscript, DAWN, OPACS, VRML 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++ Modules for space applications Delayed radioactivity General purpose source particle module Particle source and spectrum INTEGRAL and other science missions Low-energy e.m. extensions Geological surveys of asteroids Sector Shielding Analysis Tool CAD tool front-end Instrument design purposes Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Dose calculations Courtesy of P. Nieminen, ESA Interface to external tools Through abstract interfaces AIDA No dependence Minimize coupling of components Courtesy of A. Pfeiffer, CERN Example: AIDA & Analysis Tools Similar approach: Lizard Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Java Analysis Studio graphics (G)UI persistency etc. BaBar Courtesy of D. Wright for the BaBar Collaboration Preliminary Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Example of integrated Fast/Full Simulation application BaBar Object-oriented Geant4-based Unified Simulation (BOGUS) Integrated framework for Fast and Full simulation Fast simulation available for public use since February 1999 Integrated in BaBar environment primary generators, reconstruction, OODB persistency parameters for materials and geometry shared with reconstruction applications Exploits Geant4 parameterisation (new feature) Courtesy of G. Cosmo for the BaBar Collaboration 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) Preliminary Liquid Ar calorimeter Fcal energy resolution Muon detector Courtesy of D. Barberis for ATLAS Collaboration Maria Grazia Pia, INFN Genova - EPS-HEP 2001 HARP with GEANT4 Courtesy of P. Arce for the HARP Collaboration Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Preliminary Sophisticated geometry Very non-uniform strong magnetic field Primary target as a particle source T9 beam line Simulation (10 GeV/c) Measurement Beam spot width (mm) 3.27 approx. 4 Beam spot height (mm) 3.49 approx. 4 Beam spot position (mm) (0.33:0.86) (0.0:0.0) Beam profile and composition at the HARP target Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Crucial to have a precise absolute knowledge of the particle rate incident onto HARP target Impossible to separate experimentally from m in the beam with the accuracy required Courtesy of P. Arce for the HARP Collaboration GLAST (gray telescope) Preliminary GLAST Courtesy of F. Longo and R. Giannitrapani, GLAST Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Cosmic rays, jovian electrons Other astroparticle applications Solar system explorations Courtesy SOHO EIT Solar X-rays, e, p unique simulation capabilities: low E physics fluorescence radioactivity neutrons space modules etc.. Courtesy of R. Nartallo, ESA X-ray telescope Courtesy of S. Magni, Borexino XMM ZEPLIN III Dark Matter, Boulby mine Maria Grazia Pia, INFN Genova - EPS-HEP 2001 Courtesy of A. Howard, UKDM anisotropy Technology transfer Medical applications of Geant4: radiotherapy PET dosimetry etc. Brachytherapy Ir 192 Distance along longitudinal axis (mm) Courtesy National Inst. for Cancer Research, Genova Isodoses 40 30 Treatment planning Isodose 200% 150% 100% 75% 50% 25% 20 10 0 Courtesy LIP & Portuguese Oncological Institute data Histogram: Geant4 -10 -20 Commercial treatment planning system -30 -40 -40 -30 -20 -10 0 10 20 30 40 Distance along transverse axis (mm) 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. Maria Grazia Pia, INFN Genova - EPS-HEP 2001