Hadron Physics II
KOI, Tatsumi
SLAC National Accelerator Laboratory
Geant4 v9.4
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1
Overview
• Low Energy Neutron Physics
– High Precision Neutron Models
• Ion Physics
– Inelastic
– Electromagnetic Dissociation
– Radio Active Decay
Geant4 v9.4
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2
Low energy (< 20MeV) neutrons
physics
• High Precision Neutron Models (and Cross Section Data
Sets)
– G4NDL
• ENDF
–
–
–
–
Elastic
Inelastic
Capture
Fission
• NeutronHPorLEModel(s)
• ThermalScatteringModels ( and Cross Section data
Sets)
• JENDL High Energy Files ( cross sections < 3GeV)
Geant4 v9.4
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G4NDL
(Geant4 Neutron Data Library)
• The neutron data files for High Precision Neutron models
• The data are including both cross sections and final states.
• The data are derived evaluations based on the following evaluated
data libraries (in alphabetic order)
–
–
–
–
–
–
–
–
–
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
• The data format is similar ENDF, however it is not equal to.
Geant4 v9.4
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Evaluated Nuclear Data File-6
• “ENDF” is used in two meanings
• One is Data Formats and Procedures
– How to write Nuclear Data files
– How to use the Nuclear Data files
• The other is name of recommended libraries of USA nuclear data projects.
– ENDF/B-VI.8
• 313 isotopes including 5 isomers
• 15 elements
– ENDF/B-VII.0
• Released on 2006 Dec
• almost 400 isotopes
• not yet migrated
• After G4NDL3.8 (3.14 is the latest) we concentrated translation from ENDF
library.
– No more evaluation by ourselves.
Geant4 v9.4
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G4NeutronHPElastic
• The final state of elastic scattering is described by
sampling the differential scattering cross-sections
– tabulation of the differential cross-section
d d
cos  , E 

d d
– a series of legendre polynomials and the legendre
coefficients
nl
2 d
2l  1
cos , E   
al E Pl cos  
 E  d
2
l 0
Geant4 v9.4
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G4NeutronHPInelastic
• Currently supported final states are (nA ) nγs (discrete and
continuum), np, nd, nt, n 3He, nα, nd2α, nt2α , n2p, n2α,
np , n3α, 2nα, 2np, 2nd, 2nα, 2n2α, nX, 3n, 3np, 3nα, 4n, p,
pd, pα, 2pd, dα, d2α, dt, t, t2α, 3He, α, 2α, and 3α.
• Secondary distribution probabilities are supported
–
–
–
–
isotropic emission
discrete two-body kinematics
N-body phase-space distribution
continuum energy-angle distributions
• legendre polynomials and tabulation distribution
• Kalbach-Mann systematic
A + a → C → B + b, C:compound
nucleus
– continuum angle-energy distributions in the laboratory system
Geant4 v9.4
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G4NeutronHPCapture
• The final state of radiative capture is described by either
photon multiplicities, or photon production cross-sections,
and the discrete and continuous contributions to the
photon energy spectra, along with the angular distributions
of the emitted photons.
• For discrete photon emissions
– the multiplicities or the cross-sections are given from data
libraries
• For continuum contribution
– E neutron kinetic energy, Eγ photon energies
f E  E    pi E gi E  E 
i data libraries
– pi and gi are given from
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8
G4NeutronHPFission
• Currently only Uranium data are available in G4NDL
• first chance, second chance, third chance and forth
chance fission are into accounted.
• The neutron energy distributions are implemented in
six different possibilities.
– tabulated as a normalized function of the incoming and
outgoing neutron energy
- f E  E
– Maxwell spectrum
- f E  E  Ee  
 
– a general evaporation spectrum
- f E  E  Ee
– evaporation spectrum
- f E  E  f  E E 
– the energy dependent Watt spectrum - f E  E  e   sinh b(E)E
– the Madland Nix spectrum
1
f E  E   g E , K   g E , K 
2
E  E
E  E
E a E
l
Geant4 v9.4
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9
Verification of High Precision Neutron models
Channel Cross Sections
20MeV neutron on 157Gd
10
Geant4 results are derived
from thin target calculations
CrossSection [barn]
1
G4
ENDF
0.1
0.01
Geant4 v9.4
Inelastic
Inelastic
Inelastic
Inelastic
Inelastic
Inelastic
Capture
Elastic
0.001
(n,nγ)
(n,2n)
(n,nα)
(n,np)
(n,p)
(n,α)
Geant4 Tutorial at Texas A&M 12Jan-2011
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Verification of High Precision Neutron
models
Energy Spectrum of Secondary Particles
Gd154 (n,2n) channel
4.5E-07
4.0E-07
3.5E-07
3.0E-07
2.5E-07
2.0E-07
1.5E-07
1.0E-07
5.0E-08
0.0E+00
ENDF
G4 result
0
Geant4 v9.4
2E+06 4E+06 6E+06 8E+06 1E+07 1E+07
secondary neutron energy [eV]
Geant4 Tutorial at Texas A&M 12Jan-2011
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G4NeutornHPorLEModels
• Many elements remained without data for High
Precision models.
• Those models make up for such data deficit.
• If the High Precision data are not available for a
reaction, then Low Energy Parameterization
Models will handle the reaction.
• Those can be used for not only for models (final
state generator) but also for cross sections.
• Elastic, Inelastic, Capture and Fission models are
prepared.
Geant4 v9.4
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Thermal neutron scattering from
chemically bound atoms
• At thermal neutron energies, atomic translational
motion as well as vibration and rotation of the
chemically bound atoms affect the neutron
scattering cross section and the energy and
angular distribution of secondary neutrons.
• The energy loss or gain of incident neutrons can
be different from interactions with nuclei in
unbound atoms.
• Only individual Maxwellian motion of the target
nucleus (Free Gas Model) was taken into account
the default NeutronHP models.
Geant4 v9.4
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Thermal neutron scattering files from
the evaluated nuclear data files
ENDF/B-VI, Release2
• These files constitute a thermal sub-library
• Use 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
• The files and NJOY are required to prepare the
scattering law S(α,β) and related quantities.
Geant4 v9.4
b
E
S  ,   ;
2kT E
E   E  2 E E 
E  E
momentum transfer
:


,
energy
tra
nsfer
:


Geant4 Tutorial at Texas A&M 12kT14
Jan-2011 AkT
Scattering cross section :  E  E,   
Cross section and Secondary Neutron
Distributions using S(α, β) model
Energy Spectrum of
Neutron Scattering on Hydrogen within polyethylene at 300 K
Angular distribution
neutron scattering on Hydrogen within polyethylene 300 K
0.04
12.0
8.0
4.0
0.03
relative ratio
0.1eV FreeGas
0.1eV S(α, β)
1eV FreeGas
1eV S(α, β)
0.1eV FreeGas
0.1eV S(α, β)
1eV FreeGas
1eV S(α, β)
0.02
0.01
0.0
1.0E-05
1.0E-03
1.0E-01
1.0E+01
0.00
-1
energy [eV]
-0.5
Neutron scattering on Hydrogen within polyethylene at 300K
0
0.5
1
μ = cos(θ）
1.0E+04
cross sectin [barn]
relative ratio [ /eV/bin]
16.0
1.0E+03
Free Gas Model
Inelastic
Incoherent elastic
1.0E+02
1.0E+01
1.0E+00
1.0E-01
1.0E-05 1.0E-02 1.0E+01 1.0E+04 1.0E+07
Geant4 v9.4
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[eV]
Jan-2011
15
Japanese Evaluated Nuclear Data
Library (JENDL)
High Energy Files 2007
• JENDL are been making by the Nuclear Data
Evaluation Center of Japan Atomic Energy
Agency with the aid of Japanese Nuclear Data
Committee
• High Energy Files 2007
– Neutron- and proton-induced reaction data up to
3 GeV for 107 nuclides.
– We introduced its cross sections except for Am
Geant4 v9.4
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Neutron Cross Section on Iron
4.5
Cross Section [barn]
4
3.5
JENDL Fe56 tot
JENDL Fe56 ela
JENDL Fe56 inela
QGSP_BERT_HP tot
QGSP_BERT_HP ela
QGSP_BERT_HP inela
3
2.5
2
1.5
1
0.5
1.0E+08
1.0E+09
1.0E+10
Neutron Energy [eV]
1.0E+11
Difference of Cross Section
σJENDL_HE - σQGSP_BERT_HP
Comparison JEND HE files
to Cross Sections which used in
QGSP_BERT_HP physics lists
Comparison carried out
at Geant4 v8.0.p01
5.0E-01
4.0E-01
delta Cross Section [barn]
0
1.0E+07
3.0E-01
2.0E-01
1.0E-01
0.0E+00
1.0E+07
-1.0E-01
1.0E+08
1.0E+09
1.0E+10
1.0E+11
Total
Elastic
Inelastic
-2.0E-01
-3.0E-01
-4.0E-01
Geant4 v9.4
-5.0E-01
Geant4
Tutorial at Texas A&M 12Primary Neutron Energy [eV]
Jan-2011
17
Physics List for 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 );
Geant4 v9.4
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Physics List for NeutronHPorLE
• //For example Elastic scattering below 20 MeV
• G4HadronElasticProcess* theNeutronElasticProcess = new
G4HadronElasticProcess();
• // Model
• G4NeutronHPorLElasticModel* theNeutronElasticModel = new
G4NeutronHPorLElasticModel();
• theNeutronElasticProcess->RegisterMe(theNeutronElasticModel)
• // Cross Section Data set
• theNeutronElasticProcess->AddDataSet( theNeutronElasticModel>GiveHPXSectionDataSet() );
• G4ProcessManager* pmanager = G4Neutron::Neutron()->
GetProcessManager();
• pmanager->AddDiscreteProcess( theNeutronElasticProcess );
Geant4 v9.4
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Physics List for
NeutronHPThermalScattering
•
•
•
•
•
•
•
G4HadronElasticProcess* theNeutronElasticProcess = new G4HadronElasticProcess();
// Cross Section Data set
G4NeutronHPElasticData* theHPElasticData = new G4NeutronHPElasticData();
theNeutronElasticProcess->AddDataSet( theHPElasticData );
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);
•
•
•
// Apply Processes to Process Manager of Neutron
G4ProcessManager* pmanager = G4Neutron::Neutron()-> GetProcessManager();
pmanager->AddDiscreteProcess( theNeutronElasticProcess );
•
•
•
•
•
•
Geant4 v9.4
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Material Definitions for
NeutronHPThermalScattering
•
•
// Create Element 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" , density = 1.0*g/cm3 ,
ncomponents = 2 );
matH2O_TS -> AddElement(elTSHW,natoms=2);
matH2O_TS -> AddElement(elO,natoms=1);
•
•
•
•
•
G4Material* matCH2_TS = new G4Material( "Polyethylene_TS" , density =
0.94*g/cm3 , ncomponents = 2 );
matCH2_TS -> AddElement(elTSH,natoms=2);
matCH2_TS -> AddElement(elC,natoms=1);
Geant4 v9.4
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Physics List for
JENDL High energy cross sections
•
•
•
•
•
•
•
•
//For example Elastic scattering below 3 GeV
G4HadronElasticProcess* theNeutronElasticProcess = new
G4HadronElasticProcess();
// Cross Section Data set ( HP < 20MeV < JENDL HE)
G4NeutronHPElasticData* theHPElasticData = new G4NeutronHPElasticData();
theNeutronElasticProcess->AddDataSet( theNeutronElasticModel>GiveHPXSectionDataSet() );
theNeutronElasticProcess->AddDataSet( theHPElasticData );
G4NeutronHPJENDLHEData* theJENDLHEElasticData = new
G4NeutronHPJENDLHEData();
theNeutronElasticProcess->AddDataSet(theJENDLHEElasticData);
•
•
Geant4 v9.4
G4ProcessManager* pmanager = G4Neutron::Neutron()->
GetProcessManager();
pmanager->AddDiscreteProcess( theNeutronElasticProcess );
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Ion Physics
Inelastic Reactions
• Cross Sections
• Model
– G4BinaryLightIon
– G4WilsonAbrasion
– G4QMD
Geant4 v9.4
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Cross Sections
• Many cross section formulae for NN collisions
are included in Geant4
– Tripathi, Shen, Kox and Sihver
• These are empirical and parameterized
formulae with theoretical insights.
• G4GeneralSpaceNNCrossSection was prepared
to assist users in selecting the appropriate
cross section formula.
Geant4 v9.4
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References to NN Cross Section
Formulae implemented in Geant4
• Tripathi Formula
– NASA Technical Paper TP-3621 (1997)
• Tripathi Light System
– NASA Technical Paper TP-209726 (1999)
• Kox Formula
– Phys. Rev. C 35 1678 (1987)
• Shen Formula
– Nuclear Physics. A 49 1130 (1989)
• Sihver Formula
– Phys. Rev. C 47 1225 (1993)
Geant4 v9.4
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Inelastic Cross Section
C12 on C12
Geant4 v9.4
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Binary Cascade
~Model Principals~
• In Binary Cascade, each participating nucleon is seen as a
Gaussian wave packet, (like QMD)
4
 2



2
 x, qi , pi , t    L  exp
2  ipi t x 





L
x

q
t


i


3
• Total wave function of the nucleus is assumed to be direct
product of these. (no anti-symmetrization)
• This wave form have same structure as the classical
Hamilton equations and can be solved numerically.
• The Hamiltonian is calculated using simple time
independent optical potential. (unlike QMD)
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Binary Cascade
~nuclear model ~
• 3 dimensional model of the nucleus is
constructed from A and Z.
• Nucleon distribution follows
– A>16 Woods-Saxon model
– Light nuclei harmonic-oscillator shell model
• Nucleon momenta are sampled from 0 to
Fermi momentum and sum of these momenta
is set to 0.
• time-invariant scalar optical potential is used.
Geant4 v9.4
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Binary Cascade
~ G4BinaryLightIonReaction ~
• Two nuclei are prepared according to this model
(previous page).
• The lighter nucleus is selected to be projectile.
• Nucleons in the projectile are entered with
position and momenta into the initial collision
state.
• Until first collision of each nucleon, its Fermi
motion is neglected in tracking.
• Fermi motion and the nuclear field are taken into
account in collision probabilities and final states
of the collisions.
Geant4 v9.4
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Validation results
Neutrons from 400MeV/n Ne20 on
Carbon
Geant4 v9.4
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Neutron Yield
Fe 400 MeV/n beams
Copper Thick Target
Geant4 v9.4
Lead Thick Target
Geant4 Tutorial at Texas A&M 12Jan-2011
T. Kurosawa et al.,
Phys. Rev. C62
31
pp. 04461501 (2000)
Fragment Production
Si 453 MeV/n on Al
Si 490 MeV/n on Cu
1000
100
DATA
G4
10
1
100
DATA
G4
10
1
Al Mg Na Ne F O
Particle Species
Geant4 v9.4
Cross Section [mb]
Cross Section [mb]
1000
N
C
Al Mg Na Ne F O
Particle Species
Geant4 Tutorial at Texas A&M 12Jan-2011
N
C
F. Flesch et al.,
J, RM, 34 237 2001
32
G4WilsonAbrasionModel &
G4WilsonAblationModel
• G4WilsonAbrasionModel is a simplified macroscopic model for
nuclear-nuclear interactions based largely on geometric arguments
• The speed of the simulation is found to be faster than models such
as G4BinaryCascade, but at the cost of accuracy.
• A nuclear ablation has been developed to provide a better
approximation for the final nuclear fragment from an abrasion
interaction.
• Performing an ablation process to simulate the de-excitation of the
nuclear pre-fragments, nuclear de-excitation models within Geant4
(default).
• G4WilsonAblationModel also prepared and uses the same approach
for selecting the final-state nucleus as NUCFRG2 (NASA TP 3533)
Geant4 v9.4
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Abrasion & Ablation
Abrasion
process
projectile
target
nucleus
Ablation
process
Geant4 v9.4
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Validation of G4WilsonAbrasion model
12
C-C 1050 MeV/nuc
Abrasion + ablation
Experiment
NUCFRG2
cross-section [mb]
100.0
10.0
1.0
0.1
C11
C10
B11
B10
Be10
Be9
Be7
Li8
Li7
Li6
He6
Fragment
Geant4 v9.4
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G4QMD
• Binary Light Ion Cascade is an Ion extension of Binary Cascade
• However, in the model
– Neglects participant-participant scattering
– Uses simple time independent optical potential
– Does not provide ground state nucleus which can be used in molecular
dynamics
• The solution for overcoming these limitation and enabling the simulation
of real HZE reactions is QMD (Quantum Molecular Dynamics)
• QMD is quantum extension of classical molecular-dynamics model.
– Each nucleon is seen as a Gaussian wave packet
– Propagation with scattering term which takes into account Pauli principal
Geant4 v9.4
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G4QMD
• G4QMD create ground state nucleus based on JQMD, which can be
used in MD
• Potential field and field parameters of G4QMD is also based on
JQMD with Lorentz scalar modifications
– “Development of Jaeri QMD Code” Niita et al, JAERI-Data/Code 99-042
• Self generating potential field is used in G4QMD
• G4QMD uses scattering and decay library of Geant4
– Following 25 resonances are taken into account
– Δ from 1232 up to 1950
– N from 1400 up to 2250
• G4QMD includes Participant-Participant Scattering
• All major limitations of Binary cascade for Nucleus-Nucleus
calculations are cleared in G4QMD
Geant4 v9.4
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37
Ar40 560MeV/n on Lead
Secondary neutron spectra
+ Data
+ G4BinaryCascade
+ G4QMD
Geant4 v9.4
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“Energy deposition in intermediate-energy nucleon–
nucleus collisions,” Kwiatkowski et al., Phys. Rev. Lett.,
vol. 50, no. 21, pp. 1648–1651, 1983
180MeV Proton on Al
Fragment A=7
1.0E+00
cross section [mb/MeV/sr]
exp 20°
1.0E-01
exp 40°
exp 70°
G4BC 20°
1.0E-02
G4BC 40°
G4BC 70°
G4QMD 20°
1.0E-03
G4QMD 40°
G4QMD 70°
1.0E-04
0
5
10
15
20
25
30
35
40
45
frgament energy [MeV]
Geant4 v9.4
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Ion Physics
EelectorMagnetic Dissociation
• Electromagnetic dissociation is liberation of
nucleons or nuclear fragments as a result of
electromagnetic field by exchange of virtual
photons, rather than the strong nuclear force
• It is important for relativistic nuclear-nuclear
interaction, especially where the proton number
of the nucleus is large
• G4EMDissociation model and cross section are an
implementation of the NUCFRG2 (NASA TP 3533)
physics and treats this electromagnetic
dissociation (ED).
Geant4 v9.4
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Validation of
G4EMDissociaton Model
Target Emulsion nuclei: Ag 61.7%, Br 34.2%, CNO 4.0% and H 0.1%
Projectile
Energy
[GeV/nuc]
Product from
ED
G4EM
Dissociation
[mbarn]
Experiment
[mbarn]
Mg-24
3.7
Na-23 + p
124  2
154  31
Si-28
3.7
Al-27 + p
107  1
186  56
14.5
Al-27 + p
216  2
165  24†
128  33‡
200
N-15 + p
331  2
293  39†
342  22*
O-16
M A Jilany, Nucl Phys, A705, 477-493, 2002.
Geant4 v9.4
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Physics List for Binary Light Ion
•
•
•
•
•
•
•
•
•
•
•
•
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);
//Apply Processes to Process Manager of GenericIon
G4ProcessManager* pmanager = G4GenericIon:: GenericIon()->
GetProcessManager();
pmanager->AddDiscreteProcess( theIPGenericIon );
Geant4 v9.4
Geant4 Tutorial at Texas A&M 12Jan-2011
42
Physics List for WilsonAbrasion
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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;
theGenIonBC->SetMinEnergy(0*MeV);
theGenIonBC->SetMaxEnergy(0.07*GeV);
theIPGenericIon->RegisterMe(theGenIonBC);
G4WilsonAbrasionModel* theGenIonAbrasion = new G4WilsonAbrasionModel();
theIPGenericIon->RegisterMe(theGenIonAbrasion);
//Apply Processes to Process Manager of GenericIon
G4ProcessManager* pmanager = G4GenericIon:: GenericIon()-> GetProcessManager();
pmanager->AddDiscreteProcess( theIPGenericIon );
Geant4 v9.4
Geant4 Tutorial at Texas A&M 12Jan-2011
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Physics List for QMD
• 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
• G4QMDReaction * theGenIonQMD= new G4QMDReaction;
• theIPGenericIon->RegisterMe(theGenIonQMD);
• //Apply Processes to Process Manager of GenericIon
• G4ProcessManager* pmanager = G4GenericIon:: GenericIon()->
GetProcessManager();
• pmanager->AddDiscreteProcess( theIPGenericIon );
Geant4 v9.4
Geant4 Tutorial at Texas A&M 12Jan-2011
44
Physics List for EMDissociation
• G4HadronInelasticProcess* theIPGenericIon =
new
G4HadronInelasticProcess("IonInelastic",
G4GenericIon::GenericIon() );
• // Cross Section Data Set
• G4EMDissociationCrossSection* theEMDCrossSection = new
G4EMDissociationCrossSection;
• theIPGenericIon->AddDataSet( theEMDCrossSection );
• // Model
• G4EMDissociation* theEMDModel = new G4EMDissociation;
• theIPGenericIon->RegisterMe(theEMDModel);
• //Apply Processes to Process Manager of GenericIon
• G4ProcessManager* pmanager = G4GenericIon:: GenericIon()->
GetProcessManager();
• pmanager->AddDiscreteProcess( theIPGenericIon );
Geant4 v9.4
Geant4 Tutorial at Texas A&M 12Jan-2011
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Ion Physics
Radio Active Decay
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To simulate the decay of radioactive nuclei
Empirical and data-driven model
α, β+, β- decay electron capture (EC) are implemented
Data (RadioactiveDecay) derived from Evaluated
Nuclear Structure Data File (ENSDF)
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nuclear half-lives
nuclear level structure for the parent or daughter nuclide
decay branching ratios
the energy of the decay process.
• If the daughter of a nuclear decay is an excited isomer,
its prompt nuclear de-excitation is treated using the
G4PhotonEvapolation
Geant4 v9.4
Geant4 Tutorial at Texas A&M 12Jan-2011
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Radio Active Decay
• Analog sampling is default
• Biasing sampling also implemented
– The decays occur more frequently at certain times
– For a given decay mode the branching ratios can
be sampled with equal probability
– split parent nuclide into a user-defined number of
nuclides
Geant4 v9.4
Geant4 Tutorial at Texas A&M 12Jan-2011
47
Physics List for RadioactiveDecay
• G4RadioactiveDecay *theRadioactiveDecay = new
G4RadioactiveDecay();
• G4ProcessManager* pmanager =
• G4ParticleTable::GetParticleTable()>FindParticle("GenericIon")->GetProcessManager();
• pmanager ->AddProcess(theRadioactiveDecay);
• pmanager ->SetProcessOrdering(theRadioactiveDecay,
idxPostStep);
• pmanager ->SetProcessOrdering(theRadioactiveDecay,
idxAtRest); Attention : if you want calculate “triton” decay,
You must NOT create “triton”(G4Triton) in your physics list.
Geant4 v9.4
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Summary
• High Precision Neutron models are data driven
models and its used evaluated data libraries.
• However the library is not complete because
there are no data for several key elements.
• Geant4 has abundant processes for Ion
interactions with matter and also without matter.
• Without any extra modules, users may simulate
ion transportation in the complex and realistic
geometries of Geant4.
Geant4 v9.4
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