hadronic physics (ii) in geant4...

Hadronic Physics (II) in GEANT4

v9.3-p01Revised 17 June 2010

Michael H. Kelsey

SLAC National Accelerator Laboratory

GEANT4 Tutorial, BUAF Puebla, Mexico

16 Jun 2010

Had Physics (II)

Topics of Interest

Low energy Neutron Scattering

• High Precision (HP) Neutron Models

• Thermal Scattering Models

• High Energy Data Files

Ion (Nucleus) Physics

• Inelastic Scattering

• Electromagnetic Dissociation

• Radioactive Decay and Fission

Selected Validation Plots

Recommended Physics Lists

Michael H. Kelsey GEANT4 June 2010 2

Had Physics (II)

Low Energy Neutrons

Kinetic energy below about 20 MeV

High Precision Neutron Models (and cross section data)

• G4NDL, ENDF

• Elastic Scattering

• Inelastic Scattering

• Capture

• Induced Fission

G4NeutronHPorLEModels (automatic model selection)

Thermal Scattering Models (cross sections and materials)

JENDL High Energy Files (cross sections below 3 GeV)


Had Physics (II)

G4NDL and ENDF

GEANT4 Neutron Data Library

Neutron data files for HP Neutron Models

Both cross-sections and final states

Derived from multiple input data libraries

Brond-2.1, CENDL2.2, EFF-3, ENDF/B-VI.0,1,4,

FENDL/E2.0, JEF2.2, JENDL-FF, JENDL-3.1,2,

MENDL-2

Data format similar to ENDF, but not identical


Had Physics (II)

G4NDL and ENDF

Evaluated Nuclear Data File-6

Two different, related meanings

Standard for writing (format) and using Nuclear Data files

With version, specifies particlar library for US nuclear data projects

ENDF/B-VI.8: 313 isotopes, 5 isomers, 15 elements

ENDF/B-VII.0 (Dec 2006): Nearly 400 isotopes

After G4NDL3.8 (currently 3.13)

Translating from ENDF library

No further raw-data evaluation within GEANT4

Comprehensive conversion underway (SLAC/LLNL)


Had Physics (II)

G4NeutronHPElastic

Final state described by sampling differential

scattering cross-section

dσ

dΩ(cosθ, E) =

σ(E)

4π

nl∑

l=0

(2l + 1) al(E) Pl(cosθ)

Tabulated in energy bins and Legendre coefficients


Had Physics (II)

G4NeutronHPInelastic

Currently supported final states

• n,A

• n,γ [discrete and continuum]

• Fragments with one or more n, p, d, t, 3He, α

np, nd, nt, n3He, nα, nd2α, nt2α, n2p, n2α, np, n3α, 2nα, 2np, 2nd, 2nα, 2n2α,3n,

3np, 3nα, 4n, p, pd, pα, 2pd, dα, d2α, dt, t, t2α, 3He, α, 2α, 3α, nX

Secondary distribution probabilities

• Isotropic emission

• Discrete two-body kinematics

• N-body phase space

• Continuum energy-angle distributions

– Legendre polynomials and energy bins

– Kalbach-Mann compound nucleus (A + a → C → B + b)

– CM, target, and lab frames


Had Physics (II)

G4NeutronHPCapture

Final state of radiative capture

• Photon multiplicities

• Photon production cross-sections

• Discrete and continuous contributions to photon spectra

• Angular distributions of emitted photons

Discrete emission from data libraries

Multiplicities and cross-sections

Continuum: neutron En in, photon Eγ out

f(En → Eγ) =∑

i

pi(En) gi(En → Eγ)

pi and gi from data libraries


Had Physics (II)

G4NeutronHPFission

Currently only uranium data are available in G4NDL

First, second, third and fourth chance fission are included

Neutron energy distributions implemented with six options

Normalized function of

neutron energies f(E → E′)

Maxwell√

E′ exp(E′/Θ(E))

General evaporation E′ exp(E′/Θ(E))

Evaporation f(E′/Θ(E))

Energy-depended Watt exp(E′/a(E)) sinh√

b(E) E′

Madland-Nix 1

2[g(E′, 〈Kℓ〉) + g(E′, 〈Kh〉)]


Had Physics (II)

G4NeutronHPorLEModels

Many elements have no data for High Precision

models

“HPorLE” allows for missing data

If HP data not available for reaction, will fail over to

Low Energy parameterization

Can be used for both for final state generation and for

cross sections

Elastic, Inelastic, Capture and Fission models available


Had Physics (II)

Thermal Scattering in Molecules

At thermal neutron energies, bound atoms appear

different than free

Atomic translational motion

Vibration and rotation

Can affect scattering and final-state parameters

Cross sections

Energy and angular distributions

Energy loss or gain of incident neutron

Only individual Maxwellian motion of target nu-

cleus (free gas model) taken into account in

default NeutronHP models


Had Physics (II)

Thermal Scattering Materials

Because of these differences, volumes which use

the thermal scattering models must use special

G4Materials

• Element names must begin with “TS ”

• Material names must end with “ TS”

• Separate version of element for each material

Users (application developers) are responsible!

Not done automatically.


Had Physics (II)

Thermal Scattering Materials

// Create Hydrogens for Thermal Scattering

G4Element* elTSHW = new G4Element("TS_H_of_Water", "H_WATER", 1.0,

1.0079*g/mole);

G4Element* elTSH = new G4Element("TS_H_of_Polyethylene", "H_POLYETHYLENE",

1.0, 1.0079*g/mole);

// Create Materials from the elements

G4Material* matH2O_TS = new G4Material("Water_TS", dens=1.0*g/cm3, ncomp=2);

matH2O_TS -> AddElement(elTSHW,natoms=2);

matH2O_TS -> AddElement(elO,natoms=1);

G4Material* matCH2_TS = new G4Material("Polyethylene_TS", dens=0.94*g/cm3,

ncomp=2);

matCH2_TS -> AddElement(elTSH,natoms=2);

matCH2_TS -> AddElement(elC,natoms=1);


Had Physics (II)


ENDF/B-VI (Release 2) files — thermal sub-library

Uses the File 7 format of ENDF/B-VI

Divides the thermal scattering into different parts

• Coherent and incoherent elastic; no energy change

• Inelastic; loss or gain in the outgoing neutron energy

Data files and NJOY are required to prepare the

scattering law S(α, β) and related quantities


Had Physics (II)


Scattering described by function S(α, β) and related

quantities

σ(E → E ′, µ) =σb

2kT

√

E ′

ES(α, β)

Momentum transfer α =E ′ + E − 2µ

√E ′E

AkT

Energy transfer β =E ′ − E

kT


Had Physics (II)

JENDL High Energy Files (2004)

Japanese Evaluated Nuclear Data Library

• Produced by Japan Atomic Energy Agency,

Nuclear Data Evaluation Center

• with assistance of Japanese Nuclear Data

Committee

• Neutron- and proton-induced reaction data up

to 3 GeV for 66 nuclides


Had Physics (II)

Ion Physics — Inelastic

Cross Sections

• Tripathi, Shen, Kox, Sihver

• Wrapper factory for selection

Models

• Light-ion Binary Cascade

• Wilson Abrasion and Ablation

• Quantum Molecular Dynamics

• Spontaneous Fission


Had Physics (II)

Nucleus-Nucleus Cross Sections

Many formulae included in GEANT4

• Tripathi Formula, NASA Technical Paper TP-3621 (1997)

• Tripathi Light System, NASA Technical Paper TP-209726 (1999)

• Shen, Nuclear Phys. A49 1130 (1989)

• Kox, Phys. Rev. C35 1678 (1987)

• Sihver, Phys. Rev. C47 1225 (1993)

Empirical and parameterized formulae with theo-

retical insights

G4GeneralSpaceNNCrossSection assists users in se-

lecting the appropriate cross section formula


Had Physics (II)

Binary Cascade

Nucleons treated as Gaussian wave packets (c.f. QMD)

φ(x, qj , pj , t) =

(

2

Lπ

)3/4

exp

− 2

L [x − qj(t)]2+ i pj(t)x

Total nuclear w.f. assumed to be direct product, no

anti-symmetrization

Same structure as classical Hamilton’s equations: solvable

numerically

Hamiltonian calculated using simple time-independent optical

potential (unlike QMD)


Had Physics (II)

Binary Cascade

Three dimensional model of the nucleus con-

structed from A and Z

Nucleon distribution follows

• Light nuclei: harmonic-oscillator shell model

• A > 16: Woods-Saxon model

Nucleon momenta are sampled up to Fermi mo-

mentum and sum of these momenta set to 0

Time-independent scalar optical potential used


Had Physics (II)

G4BinaryLightIonReaction

Both nuclei are modelled as HO shell or W-S

Lighter nucleus is always projectile

Nucleons in projectile entered with position and

momenta into initial collision state

Until first collision of each nucleon, Fermi motion

is neglected in tracking

Fermi motion and nuclear field taken into account

in collision probabilities and final states


Had Physics (II)

Nuclear Abrasion and Ablation


Had Physics (II)

Wilson Models

G4WilsonAbrasionModel

Simplified macroscopic model for nuclear-nuclear interactions

based largely on geometric arguments

Faster than models such as Binary Cascade, but at cost of

accuracy

G4WilsonAblationModel

Nuclear ablation provides better approximation for final

nuclear fragment from an abrasion interaction

Simulates de-excitation of nuclear pre-fragments, using

nuclear de-excitation models within GEANT4 (default)

G4WilsonAblationModel uses NUCFRG2 (NASA TP 3533)

approach for selecting final-state nucleus


Had Physics (II)

Quantum Molecular Dynamics

Quantum extension of classical molecular-

dynamics model

Each nucleon is seen as a Gaussian wave

packet

Propagation with scattering term, including

Pauli exclusion

Widely used to analyze various aspects of

heavy ion reactions


Had Physics (II)

G4QMD Implementation

Native C++ (not “translated” from FORTRAN)

Ground state nucleus, potential and field parame-

ters based on JQMD

“Development of Jaeri QMD Code,” Niita et al., JAERI-Data/Code

99-042

Uses GEANT4 scattering and decay libraries

Includes Participant-Participant Scattering

After reaction, connects to Evaporation Models


Had Physics (II)

Electromagnetic Dissociation

Liberation of nucleons or nuclear fragments by

exchange of virtual photons, rather than strong

nuclear force

Important for relativistic nuclear-nuclear interac-

tions, especially high-Z

G4EMDissociation model and cross-sections im-

plement NUCFRG2 (NASA TP 3533) physics for

electromagnetic dissociation (ED)


Had Physics (II)

Radioactive Decays

GEANT4 includes simulations of spontaneous nuclear decays

Empirical, data-driven model

α, β-decay, β+, electron capture (EC)

New in 9.3, Livermore spontaneous fission model

Data derived from ENSDF

Evaluated Nuclear Structure Data Files

• Nuclear half-lives

• Level structure for parent and daughter nuclides

• Decay branching ratios

• Energy of decay process

Excited isomers de-excited using G4PhotonEvapolation


Had Physics (II)

Radioactive Decay Sampling

Analog sampling is default

Biased sampling also implemented

• Decays occur more frequently at certain times

• For given decay mode branching ratios may be sampled

with equal probability

• Split parent nuclide into user-defined number of pseudo-

nuclides


Had Physics (II)

General Particle Source

Many users who are interested in radioactive decay

also use “general particle source”

Introduced by Makoto (see Tuesday 15:10)

General Particle Source Users Manual

⇒ good place for more detailed information

http://reat.space.qinetiq.com/gps/new gps sum files/gps sum.htm


Had Physics (II)

Summary

High Precision Neutron models are data-driven,

using “evaluated data” libraries with tabulated

parameters

Library is not complete because there are no data

for several key elements

Abundant processes for ion (nucleus) interactions:

spontaneous, particle-induced, and scattering in

matter

Without any extra modules, users may simulate ion

transportation in complex and realistic geometries


Had Physics (II)

Selected Validation Plots

• Neutron High-Precision

• Thermal Scattering

• JENDL High-Energy Files

• Nucleus-Nucleus Cross-sections

• Binary Cascade

• Wilson Abrasion

• Quantum Molecular Dynamics

• Electromagnetic Dissociation


Had Physics (II)

Sample NeutronHP Verification

Channel cross-sections: G4 results derived from thin targets

20 MeV neutron on 157Gd


Had Physics (II)

Sample NeutronHP Verification

Secondary energy spectrum


Had Physics (II)

Thermal Scattering Distributions


Had Physics (II)

JENDL Comparison Plots

Comparison with QGSP BERT HP cross-sections (G4.8.0-p01)


Had Physics (II)

Inelastic 12C on 12C


Had Physics (II)

Binary Cascade Validation

Neutron angle/energy spectra, 400 MeV/N 20Ne ⇒ C


Had Physics (II)


Neutron angle/energy spectra, 400 MeV/N 56Fe ⇒ Cu,Pb

Copper thick target Lead thick target


Had Physics (II)


Nuclear fragment production: G4 vs. experimental data


Had Physics (II)

Wilson Model Validation


Had Physics (II)

QMD Validation

Neutron angle/energy spectra, 560 MeV/N 40Ar ⇒ Pb


Had Physics (II)

QMD Validation

“Energy deposition in intermediate-energy nucleon–nucleus collisions,”

Kwiatkowski et al., Phys. Rev. Lett. 50(21), 1648 (1983)


Had Physics (II)

G4EMDissociaton Validation

Emulsion Target: Ag 61.7%, Br 34.2%, CNO 4.0% and H 0.1%

Energy Product G4EMDissoc Experiment

Projectile (GeV/N) from ED (mb) (mb)

24Mg 3.7 23Na + p 124±2 154±31

28Si 3.7 27Al + p 107±1 186±56

28Si 14.5 27Al + p 216±2 165±24†128±33‡

16O 200 15N + p 331±2 293±39†342±22⋆

M A Jilany, Nucl Phys A705, 477-493 (2002)


Had Physics (II)

Recommended Physics Lists

• NeutronHP

• NeutronHPorLE

• NeutronHPThermalScattering

• JENDL

• BinaryLightIon

• WilsonAbrasion

• QMD

• EMDissociation

• RadioactiveDecay


Had Physics (II)

NeutronHP

// For example Elastic scattering below 20 MeV

G4HadronElasticProcess*

theNeutronElasticProcess = new G4HadronElasticProcess();

// Cross Section Data set

G4NeutronHPElasticData* theHPElasticData = new G4NeutronHPElasticData();

theNeutronElasticProcess->AddDataSet(theHPElasticData);

// Model

G4NeutronHPElastic* theNeutronElasticModel = new G4NeutronHPElastic();

theNeutronElasticProcess->RegisterMe(theNeutronElasticModel)

G4ProcessManager* pmanager = G4Neutron::Neutron()->GetProcessManager();

pmanager->AddDiscreteProcess(theNeutronElasticProcess);


Had Physics (II)

NeutronHPorLE

//For example Elastic scattering below 20 MeV



// Model

G4NeutronHPorLElasticModel*

theNeutronElasticModel = new G4NeutronHPorLElasticModel();

theNeutronElasticProcess->RegisterMe(theNeutronElasticModel)


theNeutronElasticProcess->AddDataSet(theNeutronElasticModel

->GiveHPXSectionDataSet());




Had Physics (II)

NeutronHPThermalScattering






G4NeutronHPThermalScatteringData*

theHPThermalScatteringData = new G4NeutronHPThermalScatteringData();

theNeutronElasticProcess->AddDataSet(theHPThermalScatteringData);

// Models

G4NeutronHPElastic* theNeutronElasticModel = new G4NeutronHPElastic();

theNeutronElasticModel->SetMinEnergy(4.0*eV);

theNeutronElasticProcess->RegisterMe(theNeutronElasticModel);

G4NeutronHPThermalScattering*

theNeutronThermalElasticModel = new G4NeutronHPThermalScattering();

theNeutronThermalElasticModel->SetMaxEnergy(4.0*eV);

theNeutronElasticProcess->RegisterMe(theNeutronThermalElasticModel);

G4ProcessManager* pmanager = G4Neutron::Neutron()-> GetProcessManager();



Had Physics (II)

JENDL

// For example Elastic scattering below 3 GeV



// Cross Section Data set (HP < 20MeV < JENDL HE)


theNeutronElasticProcess->AddDataSet(theNeutronElasticModel

->GiveHPXSectionDataSet());


G4NeutronHPJENDLHEData* theJENDLHEElasticData = new G4NeutronHPJENDLHEData();

theNeutronElasticProcess->AddDataSet(theJENDLHEElasticData);




Had Physics (II)

BinaryLightIon

G4HadronInelasticProcess* theIPGenericIon =

new G4HadronInelasticProcess("IonInelastic", G4GenericIon::GenericIon());

// Cross Section Data Set

G4TripathiCrossSection* TripathiCrossSection = new G4TripathiCrossSection;

G4IonsShenCrossSection* aShen = new G4IonsShenCrossSection;

theIPGenericIon->AddDataSet(aShen);

theIPGenericIon->AddDataSet(TripathiCrossSection);

// Model

G4BinaryLightIonReaction* theGenIonBC= new G4BinaryLightIonReaction;

theIPGenericIon->RegisterMe(theGenIonBC);

G4ProcessManager* pmanager = G4GenericIon::GenericIon()->GetProcessManager();

pmanager->AddDiscreteProcess(theIPGenericIon);


Had Physics (II)

WilsonAbrasion








// Model

G4BinaryLightIonReaction* theGenIonBC= new G4BinaryLightIonReaction;

theGenIonBC->SetMinEnergy(0*MeV);

theGenIonBC->SetMaxEnergy(0.07*GeV);

theIPGenericIon->RegisterMe(theGenIonBC);

G4WilsonAbrasionModel* theGenIonAbrasion = new G4WilsonAbrasionModel();

theIPGenericIon->RegisterMe(theGenIonAbrasion);




Had Physics (II)

QMD








// Model

G4QMDReaction* theGenIonQMD = new G4QMDReaction;

theIPGenericIon->RegisterMe(theGenIonQMD);




Had Physics (II)

EMDissociation




G4EMDissociationCrossSection* theEMDCrossSection =

new G4EMDissociationCrossSection;

theIPGenericIon->AddDataSet(theEMDCrossSection);

// Model

G4EMDissociation* theEMDModel = new G4EMDissociation;

theIPGenericIon->RegisterMe(theEMDModel);




Had Physics (II)

RadioactiveDecay

const G4IonTable *theIonTable =

G4ParticleTable::GetParticleTable()->GetIonTable();

G4RadioactiveDecay *theRadioactiveDecay = new G4RadioactiveDecay();

for (G4int i=0; i<theIonTable->Entries(); i++)

G4String particleName = theIonTable->GetParticle(i)->GetParticleName();

G4String particleType = theIonTable->GetParticle(i)->GetParticleType();

if (particleName == "GenericIon")

G4ProcessManager* pmanager =

theIonTable->GetParticle(i)->GetProcessManager();

pmanager->AddProcess(theRadioactiveDecay);

pmanager->SetProcessOrdering(theRadioactiveDecay, idxPostStep);

pmanager->SetProcessOrdering(theRadioactiveDecay, idxAtRest);


hadronic physics (ii) in geant4...

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