Maria Grazia Pia,

INFN Genova

Overview

http://cern.ch/geant4/geant4.html

http://www.ge.infn.it/geant4/talks/

Maria Grazia Pia

INFN Genova [email protected]

Budker Inst. of Physics IHEP Protvino MEPHI Moscow Pittsburg University

The zoo

EGS4, EGS5, EGSnrc Geant3, Geant4 MARS MCNP, MCNPX, A3MCNP, MCNP-DSP, MCNP4B MVP, MVP-BURN Penelope Peregrine Tripoli-3, Tripoli-3 A, Tripoli-4

...and I probably forgot some more

Many codes not publicly distributed A lot of business around MC DPM EA-MC FLUKA GEM HERMES LAHET MCBEND MCU MF3D NMTC MONK MORSE RTS&T-2000 SCALE TRAX VMC++

Monte Carlo codes presented at the MC200 Conference, Lisbon, October 2000

Maria Grazia Pia,

INFN Genova

Globalisation

Sharing requirements and functionalities across diverse fields

Maria Grazia Pia,

INFN Genova

Maria Grazia Pia,

INFN Genova

Once upon a time there was a X-ray telescope...

Courtesy of NASA/CXC/SAO

Chandra X-ray Observatory Status Update September 14, 1999 MSFC/CXC CHANDRA CONTINUES TO TAKE SHARPEST IMAGES EVER; TEAM STUDIES INSTRUMENT DETECTOR CONCERN Normally every complex space facility encounters a few problems during its checkout period; even though Chandra’s has gone very smoothly, the science and engineering team is working a concern with a portion of one science instrument. The team is investigating a reduction in the energy resolution of one of two sets of X-ray detectors in the Advanced Charge-coupled Device Imaging Spectrometer (ACIS) science instrument. A series of diagnostic activities to characterize the degradation, identify possible causes, and test potential remedial procedures is underway. The degradation appeared in the front-side illuminated Charge-Coupled Device (CCD) chips of the ACIS. The instrument’s back-side illuminated chips have shown no reduction in capability and continue to perform flawlessly.

Maria Grazia Pia,

INFN Genova

What could be the source of detector damage?

Radiation belt electrons?

Scattered in the mirror shells?

Effectiveness of magnetic “brooms”?

Electron damage mechanism? - NIEL?

Other particles? Protons, cosmics?

Courtesy of R. Nartallo, ESA

XMM-Newton

ESA Space Environment & Effects Analysis Section

CCD displacement damage: front vs. back-illuminated 30 m m Si  ~1.5 MeV p+ 2 m m 30 m m

Active layer Passive layer

30 m m 2 m m

“Electron deflector” Variation in Efficiency with Proton Energy at various source half-angles

Low-E (~100 keV to few MeV), low-angle (~0 °-5°) proton scattering 1.E-04 1.E-05 1.E-06 1.E-07 1.E-08 1.E-09 0.0

Maria Grazia Pia,

INFN Genova

EPI C RG S

0.5

1.0

1.5

2.0

Proton Energy (MeV)

2.5

3.0

3.5

EPIC 0.5 deg EPIC 1 deg EPIC 4 deg EPIC 2 deg EPIC 10 deg EPIC 30 deg RGS 0.5 deg RGS 1 deg RGS 2 deg RGS 4 deg RGS 10 deg RGS 30 deg

Requirements for LowE p in

G EANT 4 L OW E NERGY E LECTROMAGNETIC P HYSICS

G E A N T 4 L O W E N E R G Y E L E C T R O M A G N E T I I C P H Y S I I C S

User Requirements Document Status: in CVS repository Version: 2.4

Project:

Geant4-LowE

Reference:

LowE-URD-V2.4

Created:

22 June 1999

Last modified:

26 March 2001

Prepared by:

Petteri Nieminen (ESA) and Maria Grazia Pia (INFN) Maria Grazia Pia,

INFN Genova

UR 2.1

The user shall be able to simulate electromagnetic interactions of positive charged hadrons down to < 1 KeV.

Need

:

Essential

Priority

:

Required by end 1999

Stability

:

T. b. d.

Source

:

Medical physics groups, PIXE

Clarity

:

Clear

Verifiability

: V

erified

OOAD…

Maria Grazia Pia,

INFN Genova

LowE Hadrons and Ions

…and validation

Experimental data: Bragg peak

Test set-up at PSI

• data O simulation INFN-Torino medical physics group Maria Grazia Pia,

INFN Genova Courtesy of R. Gotta, Thesis

Geant4 LowE Working Group

What happened next?

XMM was launched on 10 December 1999 from Kourou

Courtesy of

Maria Grazia Pia,

INFN Genova

EPIC

image of the two flaring Castor components and the brighter YY Gem

…and the other way round

Maria Grazia Pia,

INFN Genova

11

Cosmic rays, jovian electrons

Low energy e,

g

extensions

…were triggered by astrophysics requirements

X-Ray Surveys of Planets, Asteroids and Moons

Solar X-rays, e, p

Courtesy SOHO EIT

Induced X-ray line emission: indicator of target composition (~100

m

m surface layer)

Maria Grazia Pia,

INFN Genova

Geant3.21

ITS3.0, EGS4 Geant4 C, N, O line emissions included

Courtesy ESA Space Environment & Effects Analysis Section

Low Energy Processes: e,

g

250 eV up to 100 GeV

(in principle <250 eV)

Based on EPDL97, EEDL and EADL evaluated data libraries -

cross sections sampling of the final state

Maria Grazia Pia,

INFN Genova

Fe

lines Scattered photons

GaAs

lines

Photon attenuation: vs. NIST data

Testing and Validation by IST - Natl. Inst. for Cancer Research, Genova 10 1 0.1

Geant4 LowEn NIST water 0.01

0.1

Photon Energy (MeV) 1 10 Delta = (NIST-G4EMStand) / NIST Delta = (NIST-G4LowEn) / NIST 16 14 12 10 8 6 -10 -12 -14 -16 -2 -4 -6 -8 4 2 0 0.01

0.1

Photon Energy (MeV) 1 10 Maria Grazia Pia,

INFN Genova

1000 100 10 1 0.1

0.01

Fe Geant4 LowEn NIST 100 10 1 0.1

0.01

Geant4 LowEn NIST Pb 0.01

0.1

Photon energy (MeV) 1 0.01

0.1

Photon Energy (MeV) 1 10 2 0 -2 -4 -6 -8 -10 -12 -14 -16 -18 18 16 14 12 10 8 6 4 E = (NIST-G4EMStandard)/NIST E = (NIST-G4LowEn)/NIST 10 8 6 4 -4 -6 -8 -10 2 0 -2 E = (NIST - G4EM Standard)/NIST E = (NIST- G4LowEn)/NIST 0.01

0.1

Photon Energy (MeV) 1 10 0.01

0.1

Photon Energy (MeV) 1

Courtesy of S. Agostinelli, R. Corvo, F. Foppiano, S. Garelli, G. Sanguineti, M. Tropeano

…the first user application

Titanium encapsulated 125 I sources in permanent prostate implants Seed components Titanium shell (50 µm) 4.5 mm Silver core (250 µm) Exploiting X-ray fluorescence to lower the energy spectrum of photons (and electrons) and enhance the RBE

10 keV electron in water

Iodine-125 seed R. Taschereau, R. Roy, J. Pouliot

Centre Hospitalier Universitaire de Quebec, Dept. de radio-oncologie, Canada Univ. Laval, Dept. de Physique, Canada Univ. of California, San Francisco, Dept. of Radiation Oncology, USA

keV/µm Maria Grazia Pia,

INFN Genova

Terrisol GEANT4 Distance (nm)

…and the same requirements in HEP too

Si

milar requirements on both low energy e/

g

and hadrons, K-shell transitions etc. from “underground” HEP experiments

(neutrino physics, dark matter searches)

collected one year later Recent interest on these physics models from LHC for precision detector simulation

They profit of the fact that the code – does already exist – – has been extensively tested and experimentally validated by other groups Maria Grazia Pia,

INFN Genova

Evolution

Maria Grazia Pia,

INFN Genova

Why Geant4 was born How it has evolved What it is now

The historical background

Geant is a simulation tool, that provides a general infrastructure for – the description of geometry and materials – particle transport and interaction with matter – – the description of detector response visualisation of geometries, tracks and hits The user develops specific code for – – the primary event generator the geometrical description of the set up – the digitisation of the detector response

Geant3

– – has been used by most HEP experiments used also in nuclear physics experiments, medical physics, radiation background studies, space applications etc.

– – – frozen since March 1994 (Geant3.21) ~200K lines of code equivalent of ~50 man-years, along 15 years The result is a complex system – because its problem domain is complex – because it requires flexibility for a variety of applications – because its management and maintenance are complex It was not self-sufficient – hadronic physics is not native, it is handled through the interface to external packages Maria Grazia Pia,

INFN Genova

New simulation requirements

Very high statistics to be simulated – robustness and reliability Transparent physics – allowing for experimental validation Physics extensions to high energies – LHC, cosmic ray experiments...

Physics extensions to low energies – space applications, medical physics, X-ray analysis, astrophysics, radioprotection...

Reliable hadronic physics – not only for calorimetry, but also for PID applications (CP violation experiments) Exchange of CAD models ...etc.

User requirements formally collected



Geant4 URD

Maria Grazia Pia,

INFN Genova

Approved as R&D end 1994

(RD44)

– > 100 physicits and software engineers – ~ 40 institutes, international collaboration Milestone: end 1995 – OO methodology, problem domain analysis, full OOAD – tracking prototype, performance evaluation Milestone: spring 1997 –  -release, same functionality as Geant 3 – – persistency (hits), ODBMS transparency of physics models Milestone: July 1998 – public  -release Milestone: end 1998 – production release: Geant4.0

What is ?

OO Toolkit for the simulation of next generation HEP detectors

– ...of the current generation too – ...not only of HEP detectors – already used also in nuclear physics, medical physics, astrophysics, space applications, radiation background studies etc.

It is also an experiment of distributed software production and management, as a large international collaboration with the participation of various experiments, labs and institutes It is also an experiment of application of rigorous software engineering methodologies and Object Oriented technology to the HEP environment Maria Grazia Pia,

INFN Genova

The Toolkit approach

A toolkit is a set of compatible

components

– – – – – – each component is

specialised

for a specific functionality each component can be

refined

independently to a great detail components can be

integrated

at any degree of complexity it is easy to provide (and use)

alternative

components the simulation application can be

customised

by the user according to his/her needs

maintenance

and

evolution

- both of the components and of the user application - is greatly facilitated ...but what is the price to pay?

– –

the user is invested of a greater responsibility he/she must critically evaluate what he/she needs and wants to use

Maria Grazia Pia,

INFN Genova

The kit

Source code and libraries – ~1M lines of code, ~2000 classes – – continuously growing publicly downloadable from the web Documentation – 6 manuals – publicly available from the web Examples – distributed with the code – navigation between documentation and examples code – various complete applications of real-life experimental set-ups Maria Grazia Pia,

INFN Genova

Platforms – – Linux, SUN, DEC, HP Windows-NT: Visual C++ Commercial software – – none required can be interfaced to external products Free software – – gmake, g++ CLHEP Graphics & (G)UI – OpenGL, X11, OpenInventor, DAWN, VRML...

– OPACS, GAG, MOMO...

Persistency – – it is possible to run in transient mode in persistent mode use a HepDB interface, ODMG standard 22

Geant4 Collaboration

MoU based Distribution, Development and User Support of Geant4

Atlas, BaBar, CMS, HARP, LHCB CERN, JNL, KEK, SLAC, TRIUMF ESA, INFN, IN2P3, PPARC Frankfurt, Barcelona, Karolinska, Lebedev COMMON (Serpukov, Novosibirsk, Pittsburg, Northeastern, Helsinki, TERA etc.) Collaboration Board – – – manages resources and responsibilities Technical Steering Board manages scientific and technical matters Working Groups maintenance, development, QA, etc.

Members of National Institutes, Laboratories and Experiments participating in Geant4 Collaboration acquire the right to the Production Service and User Support

For others: free code and user support on best effort basis

Maria Grazia Pia,

INFN Genova

Budker Inst. of Physics IHEP Protvino MEPHI Moscow Pittsburg University

The foundation

Maria Grazia Pia,

INFN Genova

What characterizes Geant4 (i.e. the fundamental concepts, which all the rest is built upon)

Physics

From the Minutes of LCB (LHCC Computing Board) meeting, 21 October, 1997 “It was noted that experiments have requirements for

independent, alternative physics models

allow the user to

understand

produced, and hence improve the . In Geant4 these models, differently from the concept of packages, how the results are

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.” Maria Grazia Pia,

INFN Genova

Geant4 architecture

Software Engineering

plays a fundamental role in Geant4

Interface to external products w/o dependencies Domain decomposition

User Requirements • • • formally collected systematically updated PSS-05 standard

hierarchical structure of sub-domains Uni-directional flow of dependencies

• • • spiral iterative approach Software Process regular assessments and improvements (SPI process) monitored following the ISO 15504 model • • • Object Oriented methods • • OOAD use of CASE tools openness to extension and evolution contribute to the transparency of physics interface to external software without 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 • de jure and de facto Maria Grazia Pia,

INFN Genova

The functionalities

Maria Grazia Pia,

INFN Genova

What Geant4 can do How well it does it

The kernel

Run and event

multiple events – possibility to handle the pile-up multiple runs in the same job – with different geometries, materials etc.

powerful stacking mechanism – three levels by default: handle trigger studies, loopers etc.

Tracking

decoupled from physics – all processes handled through the same abstract interface independent from particle type it is possible to add new physics without affecting the tracking Geant4 has only production thresholds,

no tracking cuts



all particles are tracked down to zero range



energy, TOF ... cuts can be defined by the user

Maria Grazia Pia,

INFN Genova

Materials

Different kinds of materials can be defined –

isotopes G4Isotope

– – –

elements molecules compounds and mixtures G4Element G4Material G4Material

Attributes associated: – – – – temperature pressure state density Maria Grazia Pia,

INFN Genova

ATLAS BaBar

Geometry

Role: detailed detector description and efficient navigation Multiple representations

(same abstract interface)

CSG (Constructed Solid Geometries) simple solids STEP extensions polyhedra, spheres, cylinders, cones, toroids, etc.

ATLAS

BREPS (

B

oundary

REP

resented

S

olids) volumes defined by boundary surfaces - include solids defined by NURBS

(Non-Uniform Rational B-Splines)

Chandra

CAD exchange: ISO STEP interface Fields: of variable non-uniformity and differentiability

Borexino

Maria Grazia Pia,

External tool for g3tog4 geometry conversion INFN Genova

CMS

How to define detector geometry

Three conceptual layers – G4VSolid: shape, size – G4LogicalVolume: daughter volumes, material, sensitivity etc.

– G4VPhysicalVolume: position, rotation Placement: one positioned volume Repeated: a volume placed many times – – – reduces use of memory Replica: simple repetition (e.g. divisions) Parameterised G4VSolid G4LogicalVolume placement repeated G4VPhysicalVolume G4Box G4Material G4VisAttributes G4PVPlacement G4Tubs Maria Grazia Pia,

INFN Genova

G4VSensitiveDetector G4PVParametrized

Read-out Geometry

Readout geometry is a virtual and artificial geometry it is associated to a

sensitive detector

can be defined in parallel to the real detector geometry helps optimising the performance Maria Grazia Pia,

INFN Genova

Hits and Digis

A sensitive detector creates hits using the information provided by the G4Step One can store various types of information in a hit – – position and time of the step momentum and energy of the track – – – energy deposition of the step geometrical information etc.

A Digi represents a detector output – e.g. ADC/TDC count, trigger signal A Digi is created with one or more hits and/or other digits Hits collections are accessible – through G4Event at the end of an event – through G4SDManager during processing an event Maria Grazia Pia,

INFN Genova

Generating primary particles

Interface to Event Generators

– – through ASCII file for generators supporting /HEPEVT/ abstract interface to Lund++ Various utilities provided within the Geant4 Toolkit – ParticleGun beam of selectable particle type, energy etc.

– GeneralParticleSource provides sophisticated facilities to model a particle source used to model space radiation environments, sources of radioactivity in underground experiments etc.

– you can write your own, inheriting from

G4VUserPrimaryGeneratorAction

Particles

– – all PDG data and more, for specific Geant4 use, like ions Maria Grazia Pia,

INFN Genova

Processes

Processes describe how particles interact with material or with a volume All concrete processes derived from the same abstract interface Open to extension of physics capabilities without affecting the kernel Three basic types – At rest processes –

(eg. decay at rest)

Continuous processes –

(eg. ionization)

Discrete processes

(eg. decay in flight)

Transportation is a process – interacting with volume boundary A process which requires the shortest interaction length limits the step Maria Grazia Pia,

INFN Genova

Physics: general features

Ample spectrum of physics functionalities Uniform treatment of electromagnetic and hadronic processes Handles any type of particles – electrons, positrons, muons, photons, hadrons, ions… Distinction between processes and models –

often multiple models for the same physics process (complementary/alternative)

Open system –

users can easily create and use their own models

Transparency

(supported by encapsulation and polymorfism)

– Calculation of cross-sections independent from the way they are accessed (data files, analytical formulae etc.) – Distinction between the calculation of cross sections and their use – Calculation of the final state independent from tracking Modular design, at a fine granularity, to expose the physics Explicit use of units throughout the code Public distribution of the code, from one reference repository worldwide Maria Grazia Pia,

INFN Genova

Data libraries

Systematic collection and evaluation of experimental data from many sources worldwide Databases – ENDF/B, JENDL, FENDL, CENDL, ENSDF,JEF, BROND, EFF, MENDL, IRDF, SAID, EPDL, EEDL, EADL, SANDIA, ICRU etc.

Collaborating distribution centres – NEA, LLNL, BNL, KEK, IAEA, IHEP, TRIUMF, FNAL, Helsinki, Durham, Japan etc.

The use of evaluated data is important for the validation of physics results of the experiments

Maria Grazia Pia,

INFN Genova

37

Electromagnetic physics

     electrons and positrons g , X-ray and optical photons muons charged hadrons ions Comparable to Geant3 already in the Further extensions  release energy loss (1997)

(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, cosmic ray experiments… Low energy extensions – fundamental for space and medical applications, dark matter and n experiments, antimatter spectroscopy etc.

Alternative models for the same process

All obeying to the same abstract Process interface

Maria Grazia Pia,

INFN Genova

 transparent to tracking

Standard electromagnetic 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 Variety of models for ionisation and energy loss – including PhotoAbsorption Interaction model

(for thin layers)

Many optimised features – Secondaries produced only when needed – Sub-threshold production Maria Grazia Pia,

INFN Genova

Multiple scattering 6.56 MeV proton , 92.6 mm Si Geant4 Geant3 data Old plot, further improvements with a new model J.Vincour and P.Bem Nucl.Instr.Meth. 148. (1978) 399

shell effects

Low energy e.m.

Atomic relaxation

Fe GaAs

Bragg peak

e ,

g

down to 250 eV

(EGS4, ITS to 1 keV, Geant3 to 10 keV) Based on EPDL97, EEDL and EADL evaluated data libraries 1000 100 Geant4 LowEn NIST Photon attenuation 10 1 0.1

0.01

Maria Grazia Pia,

INFN Genova

Photon Energy (MeV) 10 Barkas effect (charge dependence) models for

negative hadrons

protons antiprotons

Hadron and ion

models based on Ziegler and ICRU data and parameterisations ions

Photo Absorption Ionisation (PAI) Model

3 GeV/c p in 1.5 cm

Ar+CH4

Ionisation energy loss produced by charged particles in thin layers of absorbers 5 GeV/c p in 20.5 m m

Si

Ionisation energy loss distribution produced by pions,

PAI model

Maria Grazia Pia,

INFN Genova

y

Polarisation

Cross section: d  d   1 2 r 0 2 h n 2 h n 2 0   h n 0 h n  h n h n 0  2 sin 2 q cos 2 f   Low Energy Polarised Compton x Sample Methods: 250 eV -100 GeV Integrating over f • Sample q • q - Energy Relation  • Sample of f Energy from P( f ) = a (b – c cos 2 f ) distribution h n 0  O x h n q  C f A q f  Polar angle Azimuthal angle Polarization vector z cos x  sin q cos f Scattered Photon Polarization  sin x  1  sin 2 q cos 2 f  N  '   1 N  cos q jˆ  sin q sin f kˆ  sin   ' ||     N iˆ  1 N sin 2 q sin f cos f jˆ  1 N sin q cos q cos f kˆ    cos  100 keV 1 MeV 10 MeV small  small  small 

More details: talk on Geant4 Low Energy Electromagnetic Physics

large  large  large  Other polarised processes under development Maria Grazia Pia,

INFN Genova

Muons

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: in-flight absorption Rayleigh scattering medium-boundary interactions (reflection, refraction)

Photon entering a light concentrator CTF-Borexino

Maria Grazia Pia,

INFN Genova

Coming soon: Penelope physics models reengineered into Geant4

Maria Grazia Pia,

INFN Genova

Hadronic physics

Completely different approach w.r.t. the past (Geant3) – – – native transparent no longer interface to external packages – clear separation between data and their use in algorithms Cross section data sets – transparent and interchangeable Final state calculation – models by particle, energy, material Maria Grazia Pia,

INFN Genova

Ample variety of models – the most complete hadronic simulation kit on the market – alternative and complementary models – it is possible to mix-and-match, with fine granularity – data-driven, parameterised and theoretical models Consequences for the users – no more confined to the black box of one package – the user has control on the physics used in the simulation, which contributes to the validation of experiment’s results

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 p N, total cross section p N, coherent elastic scattering p elastic scattering on Hydrogen Maria Grazia Pia,

INFN Genova

Parameterised and data-driven hadronic models (2)

Other models are completely new, such as: stopping particles : p , K -

(relevant for

m/p

PID detectors)

Isotope production neutrons

nuclear deexcitation absorption

Stopping

p

Neutrons

Courtesy of CMS

Energy

All

worldwide existing databases used in

neutron

transport Brond, CENDL, EFF, ENDFB, JEF, JENDL, MENDL etc.

MeV Maria Grazia Pia,

INFN Genova

Theory-driven models

Discrete transitions from ENSDF Complementary and alternative models

data Geant4 Giant Dipole Resonance

Evaporation phase

Low energy range,

pre-equilibrium,

O(100 MeV)

Theoretical model for continuum

Intermediate energy range, O(100 MeV) to O(5 GeV),

intra-nuclear transport

High energy range,

hadronic generator

régime Maria Grazia Pia,

INFN Genova

Fast simulation

Geant4 allows to perform

full

and

fast

simulation in the same environment The parameterisation process produces a direct detector response, from the knowledge of particle and volume properties – hits, digis, reconstructed-like objects

(tracks, clusters etc.)

Great flexibility – activate fast /full simulation by detector example:

full simulation for inner detectors, fast simulation for calorimeters

– activate fast /full simulation by geometry region example:

fast simulation in central areas and full simulation near cracks

– – activate fast /full simulation by particle type example:

in e.m. calorimeter, e/

g

parameterisation + full simulation of hadrons

parallel geometries in fast/full simulation example:

inner and outer tracking detectors distinct in full simulation, but handled together in fast simulation

Maria Grazia Pia,

INFN Genova

Event biasing

Geant4 provides facilities for event biasing The effect consists in producing a small number of secondaries, which are artificially recognized as a huge number of particles by their statistical weights Event biasing can be used, for instance, for the transportation of slow neutrons or in the radioactive decay simulation Various variance reduction techniques available Maria Grazia Pia,

INFN Genova

Photons: ~300 eV < E < 20 MeV

Space radiation

Electrons: ~10 keV < E < 20 MeV

environment

Galactic and extra-galactic cosmic rays

Protons: ~10 keV < E < 20 MeV Ions: ~10 keV < E < 20 MeV

Anomalous cosmic rays (Neutrinos) Jovian electrons Solar X-rays Induced emission Solar flare neutrons and g -rays Trapped particles Solar flare electrons, protons, and heavy ions Maria Grazia Pia,

INFN Genova

Modules for space applications

Delayed radioactivity

Particle source and spectrum

General purpose source particle module

INTEGRAL

and other science missions

Low-energy e.m. extensions

Instrument design purposes Maria Grazia Pia,

INFN Genova

CAD tool front-end Sector Shielding Analysis Tool

Geological surveys of solar system Dose calculations

Interface to external tools in Geant4

Through abstract interfaces

Anaphe

no dependence minimize coupling of components Similar approach Visualisation (G)UI Persistency Analysis The user is free to choose the concrete system he/she prefers for each component Maria Grazia Pia,

INFN Genova

Components and Frameworks

Frameworks are composed of components Abstract Interfaces de-couple components and frameworks

Frameworks

– correlated groups of classes (components) together with their interactions – – re-usable (generic) designs of a software system on a very high abstraction level flow of control is bi-directional between application and the framework library

Component

– – a correlated group of classes together with their interactions reusable design of (part of) a software system on a low or medium abstraction level Weakly coupled components and frameworks have large advantages – ease of re-use of component or framework – – flexibility through independence of implementation maintainability through independent evolution of components Maria Grazia Pia,

INFN Genova

Start SPS 1976 W and Z observed 1983

25 years

Start LEP 1989 WWW WWW End LEP 2000 Maria Grazia Pia,

INFN Genova

User Interface in Geant4

Two phases of user user actions – – setup of simulation control of event generation and processing User Interface category separated from actual command interpreter

(intercoms)

– – using abstract G4UIsession class several implementations exist command-line (batch and terminal) GUIs (X11/Motif, GAG, MOMO, OPACS, Java) Automatic code generation for geometry and materials (GGE, GPE) Maria Grazia Pia,

INFN Genova

Visualisation in Geant4

Control of several kinds of visualisation – – – detector geometry particle trajectories hits in the detectors Visualise the experimental set-up Visualise tracks in the experimental set-up Visualise hits Using abstract G4VisManager class – – takes 3-D data from geometry/track/hits passes on to abstract

visualization driver

G4VGraphicsSystem (initialization) G4VSceneHandler (processing 3-D data for visualisation) G4VViewer (rendering the processed 3-D data) Various drivers – OpenGL, OpenInventor, X11, Postscript, DAWN, OPACS, VRML… Maria Grazia Pia,

INFN Genova

Persistency in Geant4

Geant4 Persistency makes run, event, hits, digits and geometry information be persistent, to be read back later by user programs – – no dependence on any specific persistency model use industrial standard ODMG C++ binding and HepODBMS as persistency interface Possibility to run in transient or persistent mode File Persistent Object Time Object Database

Store( ) Retrieve( )

“ Parallel World” approach Destructor G4 kernel objects have corresponding “P” objects in G4Persistency G4Run  G4PRun G4Event G4Hit   G4PEvent G4PHit

: :

G4Persistency

Inherits from

HepPersObj

in HepODBMS

Transient Object Constructor G4Kernel G4Application G4Application Maria Grazia Pia,

INFN Genova

Data members of transient and persistent objects are copied by

Store( )

and

Retrieve( )

AIDA

Abstract Interfaces for Data Analysis

Anaphe COLT JAS OpenScientist

“The goals of the AIDA project are to define abstract interfaces for common The adoption of these interfaces should make it easier for developers and users to select to having to learn new interfaces or change their code. In addition it should be possible to physics analysis tools

use different tools

exchange data , such as histograms. without (objects) between AIDA compliant applications.” (http://aida.freehep.org) Unify/standardize “look and feel” for various tools – there is no longer “only one tool” Provide flexibility to interchange implementations of these interfaces – can use specific features of specific tools w/o change!

Histo-IF User Code Fitter-IF Allows and try to re-use existing packages – even across “language boundaries” e.g., C++ analysis using Java Histograms Maria Grazia Pia,

INFN Genova

Histo Histo Impl. 2 Fitter Fitter Impl. Y

Anaphe

http://cern.ch/anaphe/ Modular functionality for use in HEP experiments – (OO/C++) replacement of CERNLIB memory management – – I/O foundation classes – – – – histogramming minimizing/fitting visualization interactive data analysis Lizard Maria Grazia Pia,

Geant4 advanced examples

g -ray telescope X-ray telescope Underground physics and radiation background X-ray fluorescence Brachytherapy Full scale applications showing physics guidelines, advanced interactive facilities and usage of OO Analysis Tools in real-life set-ups fluorescence Fe lines GaAs lines Maria Grazia Pia,

INFN Genova

Maria Grazia Pia,

INFN Genova

The results

What experiments do with Geant4 (a very small selection among many applications…)

Maria Grazia Pia,

INFN Genova

Courtesy of D. Wright for the BaBar Collaboration

BaBar, SLAC

Preliminary

Integrated framework for Fast and Full simulation Maria Grazia Pia,

INFN Genova

ATLAS LHC, CERN

Courtesy of D. Barberis for ATLAS Collaboration

20 GeV pions 300 GeV muons

Maria Grazia Pia,

INFN Genova

TRT: Energy loss measured in ATLAS test beam compared to Geant3 and Geant4 simulations (PAI model)

HARP , CERN

( n factory studies) Sophisticated geometry Very non-uniform strong magnetic field Primary target as a particle source

T9 beam line simulation

Crucial to have a precise absolute knowledge of the particle rate incident onto HARP target Impossible to separate experimentally p from m in the beam with the accuracy required Maria Grazia Pia,

INFN Genova Courtesy of P. Arce for the HARP Collaboration

66

Underground astroparticle experiments

UKDM,

Boulby Mine unique simulation capabilities: low E physics fluorescence radioactivity neutrons space modules etc..

ZEPLIN III Dark Matter, Boulby mine

Courtesy of S. Magni, Borexino

Courtesy of H. Araujo, A. Howard, IC London Maria Grazia Pia,

INFN Genova

g

astrophysics

g

-

ray bursts AGILE GLAST NASA mission      Typical telescope:

Tracker Calorimeter Anticoincidence

g conversion electron interactions multiple scattering d -ray production charged particle tracking

GLAST

Maria Grazia Pia,

INFN Genova

GLAST

Cosmic rays, jovian electrons

Courtesy SOHO EIT

Solar system explorations

Study of the elemental composition of planets, asteroids and moons clues to solar system formation

Solar X-rays, e, p

X-ray fluorescence Arising from the solar X-ray flux, sufficient, for the inner planets, to significant fluorescence fluxes to an orbiter PIXE Significant only during particle events, during which it can exceed XRF ESA cornerstone mission to Mercury Maria Grazia Pia,

INFN Genova Courtesy of ESA Astrophysics

BepiColombo

The challenge

Geant4 has successfully coped with a variety of challenges The functionality challenge – a variety of requirements from many application domains (HEP, space, medical etc.) The physics challenge – – transparency extended coverage of physics processes across a wide energy range, with alternative models The technology challenge – first successful attempt to redesign a major package of HEP software adopting an Object Oriented environment and a rigorous approach to advanced software engineering The methodology challenge – a well defined, and continuously improving, software process has allowed to achieve the goals The performance challenge – mandatory for large scale HEP experiments and for other complex applications The geographical challenge – OOAD has provided the framework for distributed parallel development The user support challenge – the user community is distributed worldwide, operating in a variety of domains Geant4 represents not only a new, advanced simulation toolkit, but also a successful experience for the future generation of experiments Maria Grazia Pia,

INFN Genova

Tomorrow:

1 hour of medical applications

(a small selection among many results and projects in progress) Maria Grazia Pia,

INFN Genova

Information

Maria Grazia Pia,

INFN Genova

How to learn more Contacts

Documentation and examples

http://cern.ch/geant4/

Introduction to Geant4 Installation Guide Software Reference Manual – documentation of the public interface of all Geant4 classes Physics Reference Manual – extended documentation on Geant4 physics User Guide For Application Developers – for those wishing to use Geant4 User Guide For Toolkit Developers – for those wishing to extend Geant4 functionality

Contact persons: TSB representatives

(listed on the web site)

[email protected]

Examples: Novice Extended Advanced Maria Grazia Pia,

INFN Genova