a tutorial on geant4 hadronic physics (ghad) j.p. wellisch, cern/ep

A tutorial on A tutorial on geant4 hadronic geant4 hadronic physics (GHAD)physics (GHAD)

J.P. Wellisch, J.P. Wellisch,

CERN/EP.CERN/EP.

J.P. Wellisch, CERN/EP/SFT

With contributions fromWith contributions from

T. Ersmark,T. Ersmark, G. Folger,G. Folger, V.Ivanchenko,V.Ivanchenko, A. Kiryunin,A. Kiryunin, R. Nartello,R. Nartello, B. Trieu,B. Trieu, M. Verderi,M. Verderi, J.P.Wellisch,J.P.Wellisch, D. Wright.D. Wright.


ProgramProgram

How to use GHAD?How to use GHAD? Implications for detector construction.Implications for detector construction. A look inside (hadronic) processes, or A look inside (hadronic) processes, or

how to tailor.how to tailor. What models and options are What models and options are

available?available? How good is it really?How good is it really? Where to find more information.Where to find more information.

Part 1Part 1

How to use GHAD?How to use GHAD?


Physics lists – defining the Physics lists – defining the physicsphysics

GHAD physics, as all other physics, is used GHAD physics, as all other physics, is used through geant4’s physics lists.through geant4’s physics lists.

A physics lists is (user) code specifying the A physics lists is (user) code specifying the complete physics modeling used in your complete physics modeling used in your application.application. Particle typesParticle types DecaysDecays Electromagnetic physicsElectromagnetic physics ...... Hadronic physicsHadronic physics

It associates processes with particles.It associates processes with particles.


The approach to physics The approach to physics listslists


Geant4 physics lists Geant4 physics lists versus geant3 packagesversus geant3 packages

In geant4, the physics lists serve the In geant4, the physics lists serve the same purpose as the “packages” same purpose as the “packages” (GHEISHA, FLUKA, GCALOR) in geant3.(GHEISHA, FLUKA, GCALOR) in geant3.

Conceptually, the two are identical.Conceptually, the two are identical. They provide the physics and its modeling They provide the physics and its modeling

to an application.to an application. Each “package” is built of a complete and Each “package” is built of a complete and

consistent set of modelsconsistent set of models Early in geant4, the idea was that each Early in geant4, the idea was that each

user would (have to) build ‘his’ package.user would (have to) build ‘his’ package.


In the case if hadronic In the case if hadronic physics, physics, the problem was the problem was complexity.complexity.

It takes 5 levels of implementation framework It takes 5 levels of implementation framework in geant4 to implement hadronics.in geant4 to implement hadronics.

These, and the models implementing them, These, and the models implementing them, are used to assemble the hadronic physics for are used to assemble the hadronic physics for the simulation engine.the simulation engine.

The number of options is quite large.The number of options is quite large. Each comes with trade-offs in descriptive Each comes with trade-offs in descriptive

power and performance.power and performance. There are 25 particle species to be tracked, There are 25 particle species to be tracked,

that need complete and consistent physics.that need complete and consistent physics.


fis s ion(n o d e ta ils )

e las tic (n o d e ta ils )

n eu tron _ h p

evap ora tion

P recom p ou n d

G E M ch an n e ls

evap ora tion G N A S H Tran s it ion s

p rec om p ou n d

B in ary c as cad e

C H IP S Q G S F rag m en ta tion

Q G S M od e l

m od e ls

N eu tron R eac tion n eu tron _ h p

c ros s -s ec tion s

N eu tron Iso

is o top e p rod u c tion

in e las tic (w ith d e ta ils )

c ap tu re(n o d e ta ils )

p a rt ic leex: n eu tron

Assume we want to study activation.


Hence the educated guess Hence the educated guess physics lists.physics lists.

It simply became clear that writing a good physics list is It simply became clear that writing a good physics list is no trivial, in particular when hadronic physics is no trivial, in particular when hadronic physics is involved.involved.

It is nice to be able to exploit the full power in the It is nice to be able to exploit the full power in the flexibility and variety of hadronic physics modeling in flexibility and variety of hadronic physics modeling in geant4, but being forced to do so is not what we want.geant4, but being forced to do so is not what we want.

It is also nice to have the physics transparently in front It is also nice to have the physics transparently in front of you and be able to exploit it in the best possible way, of you and be able to exploit it in the best possible way, but being forced to understand it all is (very but being forced to understand it all is (very understandably) not what people want, either.understandably) not what people want, either.


Because of thisBecause of this

We have systematically accumulated experience We have systematically accumulated experience with various combinations of cross-section and with various combinations of cross-section and models over the last years.models over the last years.

Today we provide a set of physics lists Today we provide a set of physics lists institutionalizing this knowledge.institutionalizing this knowledge.

Publishing them to the general audience was Publishing them to the general audience was one of the main milestones of the hadronic one of the main milestones of the hadronic working group for 2002.working group for 2002.


Use case packages of Use case packages of Physics ListsPhysics Lists

LCG simulation project.LCG simulation project. HEP calorimetry. HEP calorimetry. HEP trackers. HEP trackers. 'Average' collider detector 'Average' collider detector Low energy dosimetric Low energy dosimetric

applicationsapplicationswith neutrons with neutrons

low energy nucleon low energy nucleon penetration shielding penetration shielding

linear collider neutron fluxeslinear collider neutron fluxes high energy penetration high energy penetration

shieldingshielding medical and other life-medical and other life-

saving neutron applicationssaving neutron applications

low energy dosimetric low energy dosimetric applications applications

high energy production high energy production targetstargetse.g. 400GeV protons on C or Bee.g. 400GeV protons on C or Be

medium energy production medium energy production targetstargetse.g. 15-50 GeV p on light targetse.g. 15-50 GeV p on light targets

LHC neutron fluxes LHC neutron fluxes Air shower applications (still Air shower applications (still

working on this)working on this) low background experimentslow background experiments

http://cmsdoc.cern.ch/~hpw/GHAD/HomePage


To make tailoring easier, and To make tailoring easier, and the code more readable, we the code more readable, we introduced Builders.introduced Builders.


You can nowYou can now Just pick a physics list from the ‘Just pick a physics list from the ‘menu’.. Aggregate your own cocktail from limited Aggregate your own cocktail from limited

complexity of the builderscomplexity of the builders Use all 5 framework levels with their full Use all 5 framework levels with their full

power.power. A structured reduction in the level of A structured reduction in the level of

complexity exposed to you.complexity exposed to you.

Now, what does this mean Now, what does this mean ??


The WWW pages – a small The WWW pages – a small demo.demo.

There is a ‘physics lists’ topic on the There is a ‘physics lists’ topic on the geant4 HyperNews. geant4 HyperNews.

We go to:We go to: http://cmsdoc.cern.ch/~hpw/GHAD/http://cmsdoc.cern.ch/~hpw/GHAD/HomePageHomePage


The recommended The recommended procedure:procedure:

Start by trying the provided physics lists.Start by trying the provided physics lists. It makes it such that results by different groups can be It makes it such that results by different groups can be

compared.compared. You will profit from validation and verification done by You will profit from validation and verification done by

others.others. Of course you are still encouraged to tailor the Of course you are still encouraged to tailor the

physics lists that we provide, and/or build your own physics lists that we provide, and/or build your own where you need.where you need.

Please also let us know about your findings.Please also let us know about your findings. Plots you may whish to provide can enter WWW for Plots you may whish to provide can enter WWW for

everyone’s benefit.everyone’s benefit.Do not use examples/novice/N04 as example for a Do not use examples/novice/N04 as example for a

hadronic physics list.hadronic physics list.


The supportThe support process – process –static viewstatic view


The support process – The support process – dynamic viewdynamic view

Part 2Part 2

Some implications for Some implications for detector constructiondetector construction


On Material constructionOn Material construction

There are three ways to construct There are three ways to construct materials in geant4materials in geant4 From it’s isotopic compositionFrom it’s isotopic composition From it’s elementsFrom it’s elements As an effective material (Aeff, Zeff)As an effective material (Aeff, Zeff)


Effective materialsEffective materials Hadronics cross-section are not a function of Hadronics cross-section are not a function of

material properties, but a function of nuclear material properties, but a function of nuclear properties.properties.

If you use effective numbers, the element If you use effective numbers, the element composition cannot be automatically recovered. composition cannot be automatically recovered.

The cross-section will be ‘highly approximativ’ at The cross-section will be ‘highly approximativ’ at best.best.

The final states will have wrong properties.The final states will have wrong properties.

Never use effective A, Z with hadronic physicsNever use effective A, Z with hadronic physics(There are situations, here you will not be able to (There are situations, here you will not be able to

avoid it, so we cannot protect against it.)avoid it, so we cannot protect against it.)


Proton induced reactionsProton induced reactions


From elementary From elementary compositioncomposition

This is good enough for most high This is good enough for most high energy applications.energy applications.


Proton induced reactionsProton induced reactions


Isotope wise compositionIsotope wise composition

When detailled simulation of low energy When detailled simulation of low energy neutrons is important, element info is not neutrons is important, element info is not sufficient (E<20MeV) to get the cross-sufficient (E<20MeV) to get the cross-section and final states right.section and final states right. For different isotopes, the neutron nuclear For different isotopes, the neutron nuclear

resonances will be at entirely different resonances will be at entirely different positionspositions

For different isotopes, the final state channels For different isotopes, the final state channels open can differ drastically.open can differ drastically.

You may be tempted to construct your You may be tempted to construct your materials from Isotopes in this casematerials from Isotopes in this case


Isotope wise compositionIsotope wise composition In case the neutron_hp models are used In case the neutron_hp models are used

(detailed neutron transport below 20MeV), (detailed neutron transport below 20MeV), geant4 recovers the natural isotopic geant4 recovers the natural isotopic composition, in case materials and composition, in case materials and mixtures are specified in terms of their mixtures are specified in terms of their constituting elements.constituting elements.

If you have enriched isotopes (like If you have enriched isotopes (like Uranium-238), please use the isotopes Uranium-238), please use the isotopes directly, to specify your material.directly, to specify your material.

Normally you do not need to use the Normally you do not need to use the G4Isotope in your detector constructionG4Isotope in your detector construction


Example: Neutrons in Example: Neutrons in LithiumLithium

Neutron inelastic cross-section at Neutron inelastic cross-section at 150eV:150eV: Li-7: 0.00 millibarnsLi-7: 0.00 millibarns Li-6: 12.2 barns !Li-6: 12.2 barns !

Open inelastic channels:Open inelastic channels: Li-7: noneLi-7: none Li-6: nLiLi-6: nLitt(which makes Li-6 a well known shielding (which makes Li-6 a well known shielding

isotope)isotope)

Part 3Part 3

A look inside (hadronic) A look inside (hadronic) processes, or how to processes, or how to

tailor.tailor.


What is tracked in What is tracked in GGEANT4EANT4 ? ?

G4Track

G4ParticleDefinition

G4DynamicParticle

G4ProcessManager

• Propagated by the tracking,• Snapshot of the particle state and location.

• Momentum, pre-assigned decay…

• The « particle type »: G4Electron, G4PionPlus…

• « Hangs » the physics sensitivity;

• The physics processes;

Process_2

Process_1

Process_3

• The classes involved in the building the « physics list » are:• The G4ParticleDefinition

concrete classes;• The G4ProcessManager;• The processes;


– PostStep actions:• Most hadronic interactions, …

The process tracking interfaceThe process tracking interface..

There are three situations, where <tracking> There are three situations, where <tracking> may want to ask information from <process>:may want to ask information from <process>:

– AlongStep:• To describe ‘continuous’ interactions, occuring along the path of the particle, like ionisation;

– AtRest:• Decay, e+ annihilation … AlongStep

PostStep


A process will implement A process will implement any combinationany combination of of the three the three AtRestAtRest, , AlongStepAlongStep and and PostStepPostStep actions:actions:

Eg: decay = AtRest + PostStepEg: decay = AtRest + PostStep Each action defines Each action defines two methodstwo methods::– GetPhysicalInteractionLength():

• Used to limit the step size:– because the process « triggers » an interaction, a decay, geometry

boundary, a user’s limit …

– DoIt():• Implements the actual action to be applied on the track;• Typically final state generation.

The process tracking interfaceThe process tracking interface..


G4VProcess & G4VProcess & G4ProcessManagerG4ProcessManager

In praxi the In praxi the G4ProcessManagerG4ProcessManager has has three three vectors of actionsvectors of actions::

One for the One for the AtRestAtRest methods of the particle;methods of the particle; One for theOne for the AlongStepAlongStep ones; ones; And one for theAnd one for the PostStepPostStep actions.actions.

It is those vectors the user sets up in the It is those vectors the user sets up in the physics list and which are used by the physics list and which are used by the tracking.tracking.


A word of caution on A word of caution on processes orderingprocesses ordering

Ordering of following processes is Ordering of following processes is criticalcritical:: Assuming Assuming nn processes, processes, the ordering of the the ordering of the

AlongGetPhysicalInteractionLengthAlongGetPhysicalInteractionLength of the last of the last processes should be:processes should be:

[n-2] …[n-2] … [n-1] multiple scattering[n-1] multiple scattering [n] transportation[n] transportation

Why ?Why ? Processes return a Processes return a « true path length »;« true path length »; The The multiple scatteringmultiple scattering « virtually folds up » this « virtually folds up » this

true path length into a true path length into a shortershorter « geometrical »« geometrical »path length;path length;

Based on this new length, the Based on this new length, the transportationtransportation can can geometrically limits the step.geometrically limits the step.

For other processes ordering does not matter.For other processes ordering does not matter.


A few examples of A few examples of processesprocesses

G4TransportationG4TransportationG4DecayG4DecayG4eIonizationG4eIonizationG4ionIonizationG4ionIonizationG4MuBremsStrahlungG4MuBremsStrahlungG4SynchrotronRadiationG4SynchrotronRadiationG4OpAbsorptionG4OpAbsorptionG4HadronElasticProcessG4HadronElasticProcessG4NeutronInelasticProcessG4NeutronInelasticProcessEtc..Etc..These are registered with the process managers by These are registered with the process managers by

the physics lists and the builders.the physics lists and the builders.


Hadronic vs. Hadronic vs. electromagnetic processeselectromagnetic processes

In EM physics (mostly): In EM physics (mostly): 1 process = 1 model and 1 cross-section.1 process = 1 model and 1 cross-section.

In hadronic physics (mostly): In hadronic physics (mostly): 1 process = an assembly and selection of many 1 process = an assembly and selection of many

cross-sections data-sets, models, production codes, cross-sections data-sets, models, production codes, model components, sub-assemblies, options. model components, sub-assemblies, options.

Default cross-section are provided for each process.Default cross-section are provided for each process. You decide in the physics list, what exactly you use.You decide in the physics list, what exactly you use. Mix, match, assemble.Mix, match, assemble.


fis s ion(n o d e ta ils )

e las tic (n o d e ta ils )

n eu tron _ h p

evap ora tion

P recom p ou n d

G E M ch an n e ls

evap ora tion G N A S H Tran s it ion s

p recom p ou n d

B in ary cascad e

C H IP S Q G S F rag m en ta tion

Q G S M od e l

m od e ls

N eu tron R eac tion n eu tron _ h p

c ross -sec tion s

N eu tron Iso

iso top e p rod u c tion

in e las tic (w ith d e ta ils )

cap tu re(n o d e ta ils )

p a rt ic leex: n eu tron

A sample inelastic process.


Cross section logic: Cross section logic: “AddDataSet(…)” fills a FILO “AddDataSet(…)” fills a FILO stackstack

Cross section baseline

Energy, particle, material, isotope, anything else

Data set 3

Data set 2

Data set 1

Reg. sequence

“GetCrossSection(…)” uses the first applicable dataset


A sketch of model A sketch of model managementmanagement

A t res t

d irec t im p lem en ta tion s

C ross sec tion fram e (L 2 )

d irec t im p lem en ta tion

D irec t im p lem en ta tion s

d irec t im p l.

frag . fu n c . im p lem en ta tion s

frag fu n c tion in te rface (L 5 )

s trin g frag . u tility fram ew ork (L 5 )

s trin g p arton fram ew ork (L 4 ) tran sp ort u tility

h ig h en erg y


evap ora tion fram ework u tility (L 5 )

p recom p ou n d u tility


C ascad e fram ew ork (L 4 ) d irec t im p lem eta tion s

sp a lla tion fram ework (L 4 )

th eory fram ew ork (L 3 )

m od e l fram e (L 2 )


iso p rod u c tion fram e (L 2 )


even t b ias in g (L 2 )

In flig h t fram ew ork (L 1 ) d irec t im p lem en ta tion s

p rocess

Part 4Part 4

What models and What models and options are available?options are available?


Cross section Cross section implementationsimplementations

Default covers all possible Default covers all possible situations for hadron interactions.situations for hadron interactions. Carried forward from geant3.21.Carried forward from geant3.21.

Different kinds of cross-section Different kinds of cross-section data setsdata sets Some are parametrizations,Some are parametrizations, Some are theory,Some are theory, Some read and use large databases.Some read and use large databases.



Low energy neutronsLow energy neutrons Data both for cross-sections and final state Data both for cross-sections and final state

generation.generation. G4NDL, based on a number of Evaluated G4NDL, based on a number of Evaluated

Nuclear Data LibrariesNuclear Data Libraries Data in a ENDF/B-VI derived data format.Data in a ENDF/B-VI derived data format. Uses the Unix file-systemUses the Unix file-system Data come from various revisions of ENDF/B, Data come from various revisions of ENDF/B,

JENDL, FENDL, CENDL, Brond, Jef, MENDL, JENDL, FENDL, CENDL, Brond, Jef, MENDL, MENDL-P, EFF, etc.. MENDL-P, EFF, etc..

Recently we started to add geant4 native Recently we started to add geant4 native evaluations.evaluations.



Proton and neutron reaction cross-Proton and neutron reaction cross-sections (Wellisch-Axen systematics)sections (Wellisch-Axen systematics) 0-20GeV for protons0-20GeV for protons 14MeV-20GeV for neutrons14MeV-20GeV for neutrons

Alternative pion cross-sectionsAlternative pion cross-sections 0-1TeV0-1TeV

Data for isotope productionData for isotope production From MENDL-2 AND MENDL-2P, and From MENDL-2 AND MENDL-2P, and

Wellisch-Axen systematics (name was Wellisch-Axen systematics (name was coined by Los Alamos).coined by Los Alamos).



Ion reaction cross-sectionsIon reaction cross-sections Tripathi’s cross-section formula for Tripathi’s cross-section formula for

E/A<1GeV, and A>2.E/A<1GeV, and A>2. Wellisch-Axen systematics for Wellisch-Axen systematics for

E/A<20GeV and A>4 for scattering off E/A<20GeV and A>4 for scattering off Hydrogen.Hydrogen.



Photo and electro-nuclear cross-sectionsPhoto and electro-nuclear cross-sections For all energiesFor all energies GammasGammas

GDR, quasi-deuteron, Delta, Roper, reggeon-GDR, quasi-deuteron, Delta, Roper, reggeon-pomeron contributions parametrizisedpomeron contributions parametrizised

Based on 14 nuclei, tested on many more…Based on 14 nuclei, tested on many more… Electrons/PositronsElectrons/Positrons

Use method of equivalent photons, and fold the Use method of equivalent photons, and fold the photo-nuclear cross-sectionphoto-nuclear cross-section

Added hard scatteringAdded hard scattering


Final state generatorsFinal state generators

Three categories of modeling Three categories of modeling approachesapproaches Parametrization driven modelingParametrization driven modeling Data driven modelingData driven modeling Theory driven modelingTheory driven modeling


Parameterisation Parameterisation driven driven models models Two domains:Two domains:

high energy inelastic (Aachen, CERN)high energy inelastic (Aachen, CERN) low energy inelastic, elastic, fission, capture (TRIUMF, low energy inelastic, elastic, fission, capture (TRIUMF,

UBC, CERN)UBC, CERN) Stopping particlesStopping particles

base line (TRIUMF, CHAOS)base line (TRIUMF, CHAOS) mu- (TRIUMF, FIDUNA)mu- (TRIUMF, FIDUNA) pi- (INFN, CERN, TRIUMF) pi- (INFN, CERN, TRIUMF) K- (Crystal Barrel, TRIUMF)K- (Crystal Barrel, TRIUMF) anti-protons (JLAB, CERN)anti-protons (JLAB, CERN) Electromagnetic transitions of the exotic atom prior to Electromagnetic transitions of the exotic atom prior to

capture; effects of atomic binding. (Novosibirsk, ESA)capture; effects of atomic binding. (Novosibirsk, ESA)


Data driven models: Data driven models:

Low energy neutron transport (neutron_hp),Low energy neutron transport (neutron_hp), Radioactive decay (DERA, ESA)Radioactive decay (DERA, ESA) photon evaporation (INFN)photon evaporation (INFN) elastic scattering (TRIUMF, U.Alberta, CERN)elastic scattering (TRIUMF, U.Alberta, CERN) internal conversion (ESA), internal conversion (ESA), etc..etc..


Theory driven modelsTheory driven models Ultra-high energy modelsUltra-high energy models

Parton transport model (U.Frankfurt, in discussion)Parton transport model (U.Frankfurt, in discussion) High energy modelsHigh energy models

‘‘Fritjof’ type string model (CERN)Fritjof’ type string model (CERN) Quark gluon String (CERN)Quark gluon String (CERN) Pythia(7) interface (Lund, CERN)Pythia(7) interface (Lund, CERN)

Intra-nuclear transport models (or replacements)Intra-nuclear transport models (or replacements) Hadronic cascade+pre-equilibrium (HIP, CERN)Hadronic cascade+pre-equilibrium (HIP, CERN) Binary and Bertini cascades (HIP, CERN, Novosibirsk, SLAC)Binary and Bertini cascades (HIP, CERN, Novosibirsk, SLAC) QMD type models (CERN, Inst.Th.Phys. Frankfurt)QMD type models (CERN, Inst.Th.Phys. Frankfurt) Chiral invariant phase-space decay (JLAB, CERN, ITEP)Chiral invariant phase-space decay (JLAB, CERN, ITEP) Partial Mars rewrite (Kyoto, Uvic, in collaboration with FNAL)Partial Mars rewrite (Kyoto, Uvic, in collaboration with FNAL)

De-excitationDe-excitation Evaporation, fission, multi-fragmentation, fermi-break-up (CMS)Evaporation, fission, multi-fragmentation, fermi-break-up (CMS)


A not totally correct hadronic model summaryA not totally correct hadronic model summary

1 MeV 10 MeV 100 MeV 1 GeV 10 GeV 100 GeV 1 TeV 10 TeV 100 TeV

CHIPS I

Absorption at restK, p-bar, n-bar

CHIPS (gamma)

QGS string

FTF string

HEP

LEP

mars

Binary cascade

Bertini cascadeRad. Dec.

conversionPhot, ev.

multifragFermi

PrecompoundFission

Evap

Neutron_hp

(I fore sure left off something, like G4LElastic)

LEpp, np


Recently released features: Recently released features:

Theoretical models:Theoretical models: Binary cascadeBinary cascade CClassical (Bertini) cascadelassical (Bertini) cascade A generic scattering term for cascade models.A generic scattering term for cascade models. Internal conversionInternal conversion Chiral invariant phase-space decay (CHIPS) for electro-Chiral invariant phase-space decay (CHIPS) for electro-

nuclear scattering with Q2>0.nuclear scattering with Q2>0. Quark gluon string Quark gluon string model for real and virtual gamma model for real and virtual gamma

reactionsreactions Auger elecAuger electrons were added.trons were added. Complete re-implementation of pre-compound.Complete re-implementation of pre-compound. HETC and GNASH transition and emission probabilities HETC and GNASH transition and emission probabilities

as options in evaporation.as options in evaporation.


More recently released features:More recently released features:

Data:Data: New photon evaporation dataNew photon evaporation data New radioaNew radioactive decay datactive decay data Neutron transport consistent with G4NDL 0.2 Neutron transport consistent with G4NDL 0.2

through 3.7.through 3.7. ParaParametrized model:metrized model:

LowLow energy parametrize energy parametrized models: Better energy d models: Better energy conservation for anti-particle and strange conservation for anti-particle and strange particle reactionparticle reaction

Mars Mars rewrite: Nrewrite: Neutron spectra extend below eutron spectra extend below 1MeV.1MeV.

Elastic scattering re-coils added.Elastic scattering re-coils added.


Even more recently released Even more recently released features:features:

Cross sectCross sections:ions: pion cross sections: A new dataset class.pion cross sections: A new dataset class. protection for low nuclear massesprotection for low nuclear masses protectionprotection for electro-nuclear (fixes CMS problem) for electro-nuclear (fixes CMS problem)

managementmanagement model clasmodel classes get deleted, no matter what the ses get deleted, no matter what the

physics list looks like.physics list looks like. tracing of originator model now possible.tracing of originator model now possible.

StoppingStopping neutrino-flavor fixed for stopping mu-neutrino-flavor fixed for stopping mu-

Many other bug-fixes and small improvementsMany other bug-fixes and small improvements ......


The recommended The recommended procedure:procedure:

Start by trying the provided physics Start by trying the provided physics lists.lists. It makes it such that results by different It makes it such that results by different

groups can be compared.groups can be compared. You will profit from validation and You will profit from validation and

verification done by others.verification done by others. It makes your (and my) life much easier.It makes your (and my) life much easier.

Part 5Part 5

Trying to answer the Trying to answer the question: question:

How good is it really?How good is it really?


Verification – grouped into Verification – grouped into sectionssections

The verification effort of the geant4 The verification effort of the geant4 hadronic working group is grouped into hadronic working group is grouped into several sections:several sections: Inclusive cross-sectionsInclusive cross-sections Thin target comparisonsThin target comparisons Verification of model componentsVerification of model components Code comparisons (least effective)Code comparisons (least effective) Complete application testsComplete application tests Robustness.Robustness.

I give few examples of each in the following I give few examples of each in the following slides.slides.

A few total cross-A few total cross-section section examplesexamples


Proton reaction cross-Proton reaction cross-section: section:

J.P.Wellisch


Pi+ reaction cross-Pi+ reaction cross-sections: dots: data, open sections: dots: data, open symbols: ‘default and symbols: ‘default and new’.new’.


Gamma-nuclear reaction Gamma-nuclear reaction cross-sections.cross-sections.

A few examples A few examples of thin target of thin target comparisonscomparisons


Particle multiplicities, QGS Particle multiplicities, QGS modelmodel


Pion production examples, Pion production examples, QGS:QGS:Rapidity distributions and invariant Rapidity distributions and invariant cross-section predictions in quark cross-section predictions in quark gluon string modelgluon string model

J.P.Wellisch

100 GeV pi+ on Gold

400GeV protons on Lithium


K+ scattering off GoldK+ scattering off Gold

QGSQGS ModelModel

Distributions of etaAnd transverse momentum.


Forward peaks in proton Forward peaks in proton induced neutron induced neutron productionproduction

Beryllium

Aluminum

Iron

Lead

256 MeV dataNeutrons at 7.5deg.


Binary cascade: Neutrons Binary cascade: Neutrons from from 597 MeV p on Pb 597 MeV p on Pb (PRC 22, (PRC 22, p1184)p1184)

Neutron productionAt 30, 60, 90, 120And 150 degrees

30 degrees

60 degrees

90 degrees

120 degrees

150 degrees

J.P.Wellisch


Low energy neutron Low energy neutron capture:capture:gammas from 14 MeV capture gammas from 14 MeV capture on Uraniumon Uranium

J.P.Wellisch

A few A few verification plots verification plots for model for model componentscomponents


4He

Nuclear densities: Ex. 4He, 10B, 28Si, and 63Cu

J.P.Wellisch


Predicting the Delta Predicting the Delta production cross-section in production cross-section in pp scattering by binary pp scattering by binary casacdecasacde

J.P.Wellisch


# prongs prediction in QGS # prongs prediction in QGS model , single pomeron model , single pomeron exchange approximation.exchange approximation.

A few code A few code comparisonscomparisons


Gammas and conversion Gammas and conversion electrons inelectrons in 57 57Co: geant4 Co: geant4 vs. RADLISTvs. RADLIST

A few A few calorimeter calorimeter simulation simulation comparisons comparisons


HEC G4 5.0 (true geometry, my toy HEC G4 5.0 (true geometry, my toy analysis)?analysis)?


ATLAS HEC G4 5.0 (true geometry, my ATLAS HEC G4 5.0 (true geometry, my toy analysis).toy analysis).

J.P.Wellisch


HEC shower shapes G4 5.0 (true HEC shower shapes G4 5.0 (true geometry, my toy analysis)geometry, my toy analysis)

Part 6Part 6

Where to find more Where to find more informationinformation


Additional reading:Additional reading:

The GHAD WWW pages.The GHAD WWW pages. http://http://cmsdoccmsdoc..cerncern..chch/~/~hpwhpw/GHAD//GHAD/

HomePageHomePage//

The LCG physics list pages.The LCG physics list pages. http://http://cmsdoccmsdoc..cerncern..chch/~/~hpwhpw/GHAD//GHAD/LCGPageLCGPage

The geant4 documentation.The geant4 documentation. http://geant4.web.http://geant4.web.cerncern..chch

/geant4/G4UsersDocuments/Overview/html/i/geant4/G4UsersDocuments/Overview/html/index.htmlndex.html