Transcript Ions

Geant4 Physics Validation and
Verification
Ions
Koi, Tatsumi SLAC/SCCS
Neutron & Ion Models
Inventory
High Precision neutron
down to thermal energy
Elastic
Inelastic
Capture
Fission
Evaporation
Fermi breakup
Multifragment
Photon Evap
Precompound
FTF String (up to 20 TeV)
QG String (up to 100 TeV)
Binary cascade
Rad. Decay
Bertini cascade
Fission
LE pp, pn
Neutrons
HEP ( up to 15 TeV)
LEP
Thermal 1 MeV
10 MeV
100 MeV
1 GeV
10 GeV 100 GeV 1 TeV (/n)
Evaporation
PreFermi breakup
compound
Multifragment
Binary cascade Light Ions
Photon Evap
Ions
Rad. Decay
Wilson Abrasion&Ablation
Electromagnetic Disosiation
Ion Physics
Inelastic Reactions
• Cross Sections
– Tripathi, Shen, Kox and Sihver Formula
• Model
– G4BinaryLightIon
– G4WilsonAbrasion
Cross Sections
• Many cross section formulae for NN collisions are
included in Geant4
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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)
• These are empirical and parameterized formulae with
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theoretical insights.
G4GeneralSpaceNNCrossSection was prepared to assist
users in selecting the appropriate cross section formula.
Inelastic Cross Section
C12 on C12
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  ip i t x 





L
x

q
t


i


3
• Total wave function of the nucleus is assumed to be
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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)
Binary Cascade
~nuclear model ~
• 3 dimensional model of the nucleus is constructed
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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
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momentum and sum of these momenta is set to 0.
time-invariant scalar optical potential is used.
Binary Cascade
~ G4BinaryLightIonReaction ~
• Two nuclei are prepared according to this model
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(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
Neutron Production
400 MeV/n Carbon on Copper
Pion Production
1 GeV/c/n Carbon
on Be, C, Cu and Pn
Geant4 6.2.p02
Binary Cascade Light Ions
Distribution of Rs
Carbon Beams
R = (σcalculate-σ measure )/σ
measure
C 290MeV/n
C 400MeV/n
200
200
100
100
Ratio %
Ratio %
Overestimate
Underestimate
0
0
-100
-100
0
20
40
60
80
Laboratory Angle [Degree]
Iwata et al.,
Phys. Rev. C64
pp. 05460901(2001)
0
20
40
60
Laboratory Angle [Degree]
Target Materials
80
Distribution of Rs
Neon Beams
Ne 600MeV/n
200
200
100
100
Ratio %
Ratio %
Ne 400MeV/n
0
-100
0
-100
0
20
40
60
80
Laboratory Angle [Degree]
Iwata et al.,
Phys. Rev. C64
pp. 05460901(2001)
0
20
40
60
80
Laboratory Angle [Degree]
Target Materials
Distribution of Rs
Argon Beams
Ar 560MeV/n
200
200
100
100
Ratio %
Ratio %
Ar 400MeV/n
0
-100
0
-100
0
20
40
60
80
Laboratory Angle [Degree]
Iwata et al.,
Phys. Rev. C64
pp. 05460901(2001)
0
20
40
60
80
Laboratory Angle [Degree]
Target Materials
Neutron Yield
Argon 400 MeV/n beams
Carbon Thick Target
Aluminium Thick Target
T. Kurosawa et al.,
Phys. Rev. C62
pp. 04461501 (2000)
Neutron Yield
Argon 400 MeV/n beams
Copper Thick Target
Lead Thick Target
T. Kurosawa et al.,
Phys. Rev. C62
pp. 04461501 (2000)
Neutron Yield
Fe 400 MeV/n beams
CarbonThick Target
Aluminum Thick Target
T. Kurosawa et al.,
Phys. Rev. C62
pp. 04461501 (2000)
Neutron Yield
Fe 400 MeV/n beams
Copper Thick Target
Lead Thick Target
T. Kurosawa et al.,
Phys. Rev. C62
pp. 04461501 (2000)
Distribution of Rs
for QMD and HIC Calculation
(done by original author)
Underestimate
100%
-100%
Overestimate
R = 1/σ measure
x(σ measure -σcalculate )
QMD
Iwata et al.,
Phys. Rev. C64
pp. 05460901(2001)
HIC
Iwata et al.,
Phys. Rev. C64
pp. 05460901(2001)
Fragmented Particles
Productions
Si 490 MeV/n on H
Si 490 MeV/n on C
1000
100
DATA
G4
10
1
Cross Section [mb]
Cross Section [mb]
1000
100
DATA
G4
10
1
Al Mg Na Ne F O
Particle Species
N
C
Al Mg Na Ne F O
Particle Species
N
C
F. Flesch et al.,
J, RM, 34 237 2001
Fragmented Particles
Productions
Si 453 MeV/n on Al
Si 490 MeV/n on Cu
1000
100
DATA
G4
10
1
Cross Section [mb]
Cross Section [mb]
1000
100
DATA
G4
10
1
Al Mg Na Ne F O
Particle Species
N
C
Al Mg Na Ne F O
Particle Species
N
C
F. Flesch et al.,
J, RM, 34 237 2001
Wilson Abrasion & Ablation
Model
• G4WilsonAbrasionModel is a simplified macroscopic
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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 deexcitation of the nuclear pre-fragments, nuclear deexcitation models within Geant4 (default).
G4WilsonAblationModel also prepared and uses the same
approach for selecting the final-state nucleus as
NUCFRG2 (NASA TP 3533)
Abrasion & Ablation
Abrasion
process
projectile
target
nucleus
Ablation
process
Validation of
G4WilsonAbrasionAblation 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
Fragment
Be7
Li8
Li7
Li6
He6
Ion Physics
EelectroMagnetic Dissociation
• Electromagnetic dissociation is liberation of
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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).
Validation of G4EMDissociaton Model
and Cross Section
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
Binay Cascade
Fragmented projectiles C12 on Water
Arrows indicated
nucleus which have
half life less than
10E-15 sec
100
10
nucleus
3He
5He
7He
9He
4Li
6Li
8Li
5Be
7Be
9Be
11Be
13Be
15Be
7B
9B
11B
13B
8C
10C
12C
1
14C
Relative intensity
1000
C12 on Water Charge Changing Cross Section
Binary Cascade, Secodaries μ>0.5, β>0.9xβprim
Charge Changing
Cross Sections
Cross Section [barn]
0.5
Binary Cascade
0.45
0.4
0.35
0
1
2
3
0.3
0.25
0.2
0.15
C12 on Water
0.1
0.05
0
100
150
200
250
300
350
Primary Energy [MeV/n]
400
450
C12 on Water Charge Changing Cross Section
G4Wilson, Secodaries μ>0.5, β>0.9xβprim
Be8s are decayed artificially
Cross Section [barn]
0.5
0.45
0.4
G4Wilson
0.35
0
1
2
3
0.3
0.25
0.2
0.15
0.1
0.05
0
100
150
200
250
300
350
Primary Energy [MeV/n]
400
450
Geant4 Validation List
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6) o Title: "Thin target neutron productions by Ions intercations"
o Brief documentation: "Ions beam on different energies incident
on different thin target materials produce
neutrons, whose kinetic energy spectra is
studied at different angles (i.e. the double
differential cross-sections are measured)."
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o Responsible person: Koi, Tatsumi SLAC/SCCS.
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o Physics List used: Specified one writen by T. K.
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o Process/Model: inelastic ions processes.
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o Level on which the validation/verification is performed: process level.
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o Primary Particles: Carbon12 290 MeV/n, 400 MeV/n
Neon20 400 MeV/n, 600 MeV/n
Argon40 400 MeV/n, 600 MeV/n
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o Target materials: Carbon, Copper, Lead.
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o Observable Values: dobule differential cross sections in [mb/sr/MeV]
of secondary neutron at 5, 10, 20, 30, 40, 60, 80 deg.
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o Data:Double-differential cross sections for the neutron production from
heavy-ion reactions at energies E/A = 290-600 MeV.
Iwata et al.,Phys. Rev. C64 pp. 05460901(2001)
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o Frequency of execution: only once, because of lack of man power.
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o Source code availability: Under Preparation
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currently only G4BinaryLightIon
future G4WilsonAbrasion
I have 10 more entries for Ions
Interactions in G4Validation List.
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6) o
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8) o
9) o
10)o
11)o
12)o
13)o
14)o
15)o
Title: "Thin target neutron productions by Ions intercations"
Title: "Ions hits on several thick target materials and measured
Title: "Pion production cross sections by ions hit on several materials"
Title: "Pion production cross sections by carbon hit on carbon"
Title: "Element production cross sections by Iron ion hit on several
Title: "Element production cross sections by Silicon ion hit on several
Title: "Fragment production cross sections by Iron ion hit on several
Title: "Fragment production cross sections by Iron ion hit on several
Title: "Fragment production cross sections by Iron ion hit on several
Title: "Fragment production cross sections by carbon hit on carbon"
Summary of validations
• Neutron DD production and Yield
– a few hundred MeV/n ~ 400 MeV/n
– Projectile C12, Ne20, Ar40, Fe56, Xs131
– Carbon to Lead Target
• Fragment Particle Production
– a few hundred MeV/n ~ a few GeV/n
– Projectile C12 to Fe56
– Carbon to Lead Target
• Element Production
– 400, 700 MeV/n
– Projectile Si28, Fe56
– H, C, Al, Cu, Ag, Pb Target
Areas where not covered by models
• High Energy [>10GeV/n] inelastic
interactions
• Elastic interactions