maria grazia pia, infn genova - eps-hep 2001 architecture of collaborating frameworks architecture...

Maria Grazia Pia, INFN Genova - EPS-HEP 2001

Architecture of collaborating frameworksArchitecture 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 PhysicsIHEP ProtvinoMEPHI Moscow Pittsburg University

CHEP 2001 ConferenceBeijing, 3-7 September 2001

http://www.ge.infn.it/geant4/lowE/index.htmlhttp://www.ge.infn.it/geant4/lowE/index.html


UKDM, Boulby Mine

GLAST

ATLAS BaBar

A rigorous approach A rigorous approach to software to software engineeringengineering

Courtesy of L3

Courtesy of the Italian Nat. Inst. for Cancer

Research

E (MeV)

Photon attenuation

An extensive set of physics processes An extensive set of physics processes and models over a wide energy rangeand models over a wide energy range

High energy Low energy photons

particle in a cell

192Ir

highlights highlights


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 A wide domain of applications with applications with

a large user a large user community in many community in many

fieldsfields

HEP, astrophysics, nuclear physics, space sciences, medical physics, radiation studies

etc.


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


GeometryGeometry

Borexino CMS

ATLAS

Chandra

XMM-Newton

Role: detailed detector description and efficient

navigation

CSGCSG (Constructed Solid Geometries)- simple solids

STEP extensionsSTEP extensions- polyhedra,, spheres, cylinders, cones, toroids, etc.

BREPSBREPS (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


Guidelines for physicsGuidelines for physics

From the Minutes of LCB (LHCC Computing Board) meeting on 21 October, 1997:

Geant4 physics keeps evolvingGeant4 physics keeps evolvingwith 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.”


Geant4 PhysicsGeant4 Physics

OOD allows to implement or modify any physics process without changing other parts of the software

open to extension and open to extension and evolutionevolution

Tracking Tracking is independent from the physics processes

The generation of the final statefinal state is independent from the access and use of cross sections

Transparent access via virtual functions to- cross sectionscross sections (formulae, data sets etc.)

- modelsmodels underlying physics processes

An abundant set of electromagneticelectromagnetic and hadronic hadronic physics processes a variety of complementary and

alternative physics modelsphysics models for most processes

Use of public evaluated databasesevaluated databases

No tracking cuts, only production production thresholdsthresholds

- thresholds for producing secondaries are expressed in rangerange, universal for all media

- converted into energy for each particle and material

The transparency of the physics implementation contributes to The transparency of the physics implementation contributes to the validation of experimental physics resultsthe validation of experimental physics results


Multiple scattering BremsstrahlungIonisationAnnihilationPhotoelectric effect Compton scattering Rayleigh effect conversione+e- pair productionSynchrotron radiationTransition radiationCherenkovRefractionReflectionAbsorptionScintillationFluorescenceAuger (in progress)

Electromagnetic physicsElectromagnetic physics

High energy extensionsHigh energy extensions- needed for LHC experiments, cosmic ray experiments…

Low energy extensionsLow energy extensions- fundamental for space and medical applications,

experiments, antimatter spectroscopy etc.

Alternative models for the same processAlternative models for the same process

energy loss

electrons and positrons , X-ray and optical photons muons charged hadrons 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


Standard e.m. processesStandard e.m. processes

Multiple scatteringMultiple scattering- new model (by L. Urbán)- computes mean free path length and

lateral displacement

New energy loss algorithmNew energy loss algorithm- optimises the generation of rays near

boundaries

Variety of modelsVariety of models for ionisation and energy loss- including the PhotoAbsorption

Interaction model

Differential and Integral approachDifferential 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)1 keV up to O(100 TeV)

Geant4Geant3data


Low energy e.m. Low energy e.m. extensionsextensions

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 parameterisationsBarkas effect

(charge dependence)models for negative hadrons

0.01 0.1 1 100.01

0.1

1

10

100

1000

Geant4 LowEn NIST

/

(cm

2 /g

) in

iron

Photon Energy (MeV)

Based on EPDL97, EEDL and EADL evaluated data libraries

Bragg peak

shell effects

Photon attenuation

antiprotons

protons ions


MuonsMuons

1 keV up to 1000 PeV scale1 keV up to 1000 PeV scalesimulation of ultra-high energy and cosmic ray physics

High energy extensions based on theoretical models

Optical photonsOptical 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


Parameterised and data-driven hadronic models (1)Parameterised and data-driven hadronic models (1)

Based on experimental dataSome 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


Other models are completely new, such as:

NeutronsCourtesy 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)Parameterised and data-driven hadronic models (2)


Theory-driven modelsTheory-driven models

Giant Dipole Resonance

Geant4data

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

Complementaryandalternativemodels


Other componentsOther 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++


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 applicationsModules for space applications

Low-energy Low-energy e.m. extensionse.m. extensions

Courtesy of P. Nieminen, ESA


Courtesy of A. Pfeiffer, CERN

Example: AIDA & Analysis Tools

Similar approach:Similar approach: graphics (G)UI persistency etc.

Interface to external toolsInterface to external tools

No dependence

Minimize coupling of components

Java Analysis Studio

Lizard

Through abstract interfaces

AIDA


BaBar BaBar

Courtesy of D. Wright for the BaBar Collaboration

Preliminary


Example of integrated Fast/Full Simulation applicationExample 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

Courtesy of G. Cosmo for the BaBar Collaboration

Exploits Geant4 parameterisation (new feature)


ATLASATLAS300 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


HARP with GEANT4HARP with GEANT4

Courtesy of P. Arce for the HARP Collaboration


T9 beam lineT9 beam line

Beam profile and composition at the HARP target

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)

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


GLAST (GLAST (ray telescope)ray telescope)

Preliminary

Courtesy of F. Longo and R. Giannitrapani, GLAST

GLAST


Other astroparticle applicationsOther astroparticle applications

Courtesy of S. Magni, Borexino

Courtesy of A. Howard, UKDM

ZEPLIN IIIDark 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


Technology transferTechnology transfer

-40 -30 -20 -10 0 10 20 30 40-40

-30

-20

-10

0

10

20

30

40

Isodose 200% 150% 100% 75% 50% 25%

Dis

tanc

e a

lon

g lo

ng

itud

inal

axi

s (m

m)

Distance along transverse axis (mm)

Brachytherapy

Courtesy National Inst. for Cancer Research, Genova

Medical applications of Geant4: radiotherapy PET dosimetry etc.

Treatment planning

anisotropy

IsodosesCourtesy LIP & Portuguese Oncological Institute

Commercial treatment planning system

data

Histogram: Geant4

192Ir


ConclusionsConclusions

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 architecture of collaborating frameworks architecture...

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