Inter-comparison of Medium-Energy Neutron Attenuation
in Iron and Concrete (8)
H. Hirayamaand
Attenuation Length Sub-Working Group
in Japan
From Inter-comparison at SATIF-9 Study the reason for the large difference in
the attenuation length and dose between codes.
It is desired to receive improved results from other groups.
Study the reason of the different tendency of C/E values between codes.
It is desired that other groups attend this inter comparisons.
Problems for an Inter-comparison (8) Problems are same with an inter-comparison (7)
Neutron dose, spectrum inside 6m iron or 12m concrete plane for parallel beam of mono-energy neutrons (0.04-100GeV) and
Secondary neutrons produced by protons (0.2-24GeV)
Comparison with the experimental results of AGS shielding experiments
As the new item to be sent by participants, “particles treated to obtain the results” is added.
Summary of contributors for Neutron attenuation calculation
Name of participantsand organization
Name of computer code
Particles treated
T. Koi and D. Wright (SLAC National
Accelerator Laboratory)
Geant4 v9.3 (2009 Dec. released)
All particles (Including recoil
nucleus)
Y. Uwamino (Riken) HETC-3STEP neutron, proton,
N. Matsuda (JAEA) and K. Niita (RIST)
PHITS 2.24 all established hadoronic states
S. Roesler (CERN) FLUKA 2008.3c. All hadrons which FLUKA
can transport
N.V. Mokhov and I.L. Rakhno (Fermilab)
MARS15(2010) All elementary particles and heavy ions
0
50
100
150
200
250
300
350
400
10 100 1000 104 105
Fig. 1 Comparison of the neutron attemuation length of iron.
ANISN(SATIF-6)MARS(SATIF-8)FLUKA(SATIF-10)HETC-3STEP(SATIF-6)ROZ-6.6(SATIF-8)PHITS(3m,SATIF-10)PHITS without
0 (3m, SATIF-10)
GEANT-4(SATIF-10)Geant-321(SATIF-8)MCNPX(SATIF-8)
Atte
nuat
ion
Len
gth
(g
cm-2
)
Source Neutron Energy (MeV)
10-20
10-18
10-16
10-14
10-12
10-10
0 100 200 300 400 500 600
Fig. 2 Dose distribution inside iron for 10 GeV protons.
ROZ-6.6(SATIF-8)FLUKA(SATIF-10)GEANT-4(SATIF-10)GEANT-321(SATIF-8)MARS(SATIF-8)PHITS(SATIF-10)PHITS(without
0)(SATIF-10)
Dos
e E
qiv
alen
t rat
e (
Sv
per
n/c
m2 )
Depthin Iron (cm)
1
10
100
1000
10 100 1000 104 105
Fig. 4 Neutron dose difference at 4m inside ironbetween ROZ 6.6, FLUKA, MARS, GEANT4 and PHITS.
Include ROZ resultMC results onlyMC results without PHITS with Lab
Ma
x./M
in.
dos
e ra
tio a
t 4
m
Source neutron energy (MeV)
Iron for mono energy neutrons General tendency of the attenuation length is
similar for all results except PHITS with 0 particle.
Differences of dose itself are large. Difference between Monte Carlo results except PHITS with
transport 0 particle is about 10. The effects of 0 particle in PHITS
The effects can be seen from 3 GeV and maximum at 10 GeV and decrees at 50 and 100 GeV.
0 portion within produced particles except neutrons and protons emitted from 1cm diameter and 1cm iron and concrete by high energy neutrons becomes maximum at 20 GeV and decrease with increase of neutron energy.
10-21
10-19
10-17
10-15
10-13
10-11
10-9
0 100 200 300 400 500 600
Fig. 5 Dose distribution inside iron by PHITS.
3GeV3 GeV without
0
5 GeV 5 GeV without
0
10 GeV10 GeV without
0
50 GeV50 GeV without
0
100 GeV100 GeV without
0
Sv
pe
r n/
cm2
Depth in iron (cm)
0
0.005
0.01
0.015
0.02
0.025
0.03
104 105
Fig.6 0 portion within produced particles
except neutrons and protons from1cm diameter and 1cm length of iron or concrete.
IronConcrete
0/to
tal (
exc
ep
t ne
utro
n a
nd p
roto
n)
Neutron Energy (MeV)
0 contribution to neutron attenuation length
Matsuda and Niita estimate the effect of 0 particle to the neutron attenuation length as follows:
The 0 particle is one of the stable baryon, which life time is 2.6x1010 sec and decayed to nucleon and pion. If the 0 particle is decayed very quickly after its production, as shown in Fig, 5, the additional contribution of 0 is disappeared. Therefore the additional contribution of the 0 particle is realized by the collisions of Lambda on material nucleus.
The mass of the 0 particles is heavier than that of nucleon. Thus much larger energy can be transported by the Lambda particles.
This is a reason, we suppose, that the attenuation through the Lambda particle is much flatter than that of not through the Lambda particle. General tendency of the attenuation length is similar for all results except PHITS with 0 particle.
It is desired to check the contribution of 0 particle to the neutron attenuation by other codes and also to compare various particles production rates from small target..
0
50
100
150
200
10 100 1000 104 105
Fig. 7 Comparison of the neutron attenuation length of concrete.
ANISN(SATIF-6)FLUKA(SATIF-10)HETC-3STEP(SATIF-8)ROZ-6.6(SATIF-8)PHITS(R=3m)(SATIF-8)GEANT-4(SATIF-10)GEANT-321(SATIF-8)MCNPX(SATIF-8)MARS(SATIF-8)
Atte
nuat
ion
Len
gth
(g
cm-2
)
Source Neutron Energy (MeV)
1
10
100
1000
0.1 1 10 100
Fig. 10 Neutron dose difference at 8m inside concrete between ROZ 6.6, FLUKA, MARS, GEANT4 and PHITS.
Include ROZ result
MC results onlyM
ax./M
in.
dose
ra
tio a
t 8m
Source neutron energy (GeV)
Concrete for mono energy neutron
General Tendencies are same with at SATIF-9. The differences between the attenuation lengths
between each code are relatively small at low-energy region and increase with the increase of neutron energy.
The attenuation length have the tendency to increase slightly with increase of neutron energy for 12 m slab.
The dose differences at 8m are about 10 or less between Monte Carlo.
Y=0 plane Y=15 plane
Y=-15 plane Y=25 plane
Z=0 plane
XZ
XZ
XZ
XZ
XY
InnerReflector
Moderator
Hg-Target
Moderator
Moderator
InnerReflector
InnerReflector
InnerReflector
InnerReflector
OuterReflector Outer
Reflector
OuterReflector
OuterReflector
OuterReflector
Hg-Target
(a) (b)
(c) (d)
(e)
Hg Target Model
Secondary neutrons produced by protons
(0.2-24GeV)
10-8
10-7
10-6
10-5
10-4
10-3
10-2
10-1
10 100 1000 104
Secondary Neutron Spectrum from a Hg TargetBombarded by 3 GeV Protons (by MCNPX)
and 24 GeV Protons (by NMTC/JAM).
24GeV p: 90-105 deg.
3 GeV p: 0-15 deg.
3 GeV p: 45-60 deg.
3 GeV p: 90-105 deg.
3 GeV p: 135-150 deg.
Neu
tro
ns
cm-2 M
eV-1
Neutron Energy (MeV)
0
40
80
120
160
100 1000 104
Fig. 13 Comparison of the neutron attenuation length of iron for secondary neutronsemiited to 90 degrees from Fe and Hg (24GeV) targer with protons.
GEANT-4(SATIF-10)ANISN(SATIF5)MARS(SATIF-8)PHITS(R=3m)(SATIF-8)HETC-3STEP(SATIF-6)ROZ-6.6(SATIF-8)FLUKA(SATIF-10)GEANT-321(SATIF-8)ISIS Exp.LANSCE Exp.
Atte
nuat
ion
Len
gth
(g c
m-2
)
Proton Energy (MeV)
Comparison with Fe Target
General Tendencies are same with at SATIF-9. All results show similar tendency to
reach an almost constant value above 1 GeV protons.
Comparison with Experimental results at AGS
Target
Concrete
Steel
Steel
5.0m
3.3m
Proton
3.7m
2.0m
0
0.5
1
1.5
2
0 50 100 150 200 250 300
209Bi(n,4n)206Bi2.83GeV, Steel
MCNPX(SATIF-9)PHITS(SATIF-9)Geant4(SATIF-10)FLUKA(SATIF-10)MARS(SATIF-10)
Cal
c./ E
xpt.
Steel Thickness (cm)
Range of Experimental Error
0
0.5
1
1.5
2
0 50 100 150 200 250 300
209Bi(n,6n)204Bi2.83GeV, Steel
MCNPX(SATIF-9)PHITS(SATIF-9)Geant4(SATIF-10)FLUKA(SATIF-10)MARS(SATIF-10)
Cal
c./ E
xpt.
Steel Thickness (cm)
Range of Experimental Error
0
0.5
1
1.5
2
0 50 100 150 200 250 300
209Bi(n,4n)206Bi24GeV, Steel
MCNPX(SATIF-9)PHITS(SATIF-9)Geant4(SATIF-10)FLUKA(SATIF-10)MARS(SATIF-10)
Cal
c./ E
xpt.
Steel Thickness (cm)
Range ofExperimental Error
0
0.5
1
1.5
2
0 50 100 150 200 250 300
209Bi(n,6n)204Bi24 GeV, Steel
MCNPX(SATIF-9)PHITS(SATIF-9)Geant4(SATIF-10)FLUKA(SATIF-10)MARS(SATIF-10)
Cal
c./ E
xpt.
Steel Thickness (cm)
Range ofExperimental Error
Steel shield
The calculated results are smaller than the measured ones in general.
The calculated results for 2.83 GeV protons are agree each other.
The C/E value differences for 24 GeV protons are larger than those for 2.83 GeV.
0
0.5
1
1.5
2
0 50 100 150 200 250 300 350 400
209Bi(n,4n)206Bi2.83 GeV, Concrete
MCNPX(SATIF-9)PHITS(SATIF-9)Geant4(SATIF-10)FLUKA(SATIF-10)MARS(SATIF-10)
Cal
c./ E
xpt.
Concrete Thickness (cm)
Range ofExperimental Error
0
0.5
1
1.5
2
0 50 100 150 200 250 300 350 400
209Bi(n,6n)204Bi2.83 GeV, Concrete
MCNPX(SATIF-9)PHITS(SATIF-9)Geant4(SATIF-10)FLUKA(SATIF-10)MARS(SATIF-10)
Cal
c./ E
xpt.
Concrete Thickness (cm)
Range ofExperimental Error
0
0.5
1
1.5
2
0 50 100 150 200 250 300 350 400
209Bi(n,4n)206Bi24 GeV, Concrete
MCNPX(SATIF-9)PHITS(SATIF-9)Geant4(SATIF-10)FLUKA(SATIF-10)MARS(SATIF-10)
Cal
c./ E
xpt.
Concrete Thickness (cm)
Range ofExperimental Error
0
0.5
1
1.5
2
0 50 100 150 200 250 300 350 400
209Bi(n,6n)204Bi24 GeV, Concrete
MCNPX(SATIF-9)PHITS(SATIF-9)Geant4(SATIF-10)FLUKA(SATIF-10)MARS(SATIF-10)
Cal
c./ E
xpt.
Concrete Thickness (cm)
Range of Experimental Error
Concrete shield
The results of PHITS, Geant4, FLUKA and MARS relatively agree well each other and with the measured results than for the steel shield.
Future Themes
0 effects for iron presented PHITS must be checked by other codes.
It is necessary to compare various produced secondary particles from small target to understand the reason of difference of dose at high energy region.
Study the reason for the large difference in the attenuation length and dose between codes.
Study the reason of difference between measured results and calculated ones by various codes and the reason of the different tendency of C/E values between codes.
Appendix
[a] High energy model switched from QGS (Quark Gluon String) to FTF (FriToF) model. Transition energy to the high energy model is lowered.
[b] Calculation only inside concrete for secondary neutrons by 24 GeV protons toward 90 degrees from a Hg target.
[c] Calculation only inside iron for 3-100 GeV neutrons.
[d] PHITS code (JAM [12]: Jet AA Microscopic Transport Model) explicitly treats all established hadoronic states including resonances with explicit spin and isospin as well as their anti-particles. All Hadron-Hadron interactions including lambda hayperon can be simulated up to 200GeV/u.
[e] Calculation only comparison with for the AGS experiments.
10-15
10-13
10-11
10-9
10-7
10 100 1000 104
Fig. 3 Neutron spectra at 4m inside iron for 10 GeV protons.
GEANT-4(4m)(SATIF-10)PHITS(4m)(SATIF-10)PHITS(4m, witout
0)(SATIF-10)
FLUKA(4m)(SATIF-10)ROZ-6.6(4m)(SATIF-8)MARS(4m)(SATIF-8)
Neu
tron
s/M
eV/c
m2 p
er n
/cm
2
Neutron Energy (MeV)
10-17
10-16
10-15
10-14
10-13
10-12
10-11
10-10
10-9
0 200 400 600 800 1000 1200
Fig. 8 Dose distribution inside concrete for 10 GeV neutrons.
ROZ-6.6(SATIF-8)FLUKA(SATIF-8)MARS-15(SATIF-8)GEANT-4GEANT-321(SATIF-8)HETC-3STEPPHITS(SATIF-8)
Dos
e E
qiv
alen
t rat
e (
Sv
per
n/c
m2 )
Depth in Concrete (cm)
10-8
10-7
10-6
10-5
10-4
10-3
10-2
10-1
10 100 1000 104
Fig. 9 Neutron spectra at 4m inside concrete for 10 GeV protons.
GEANT-4(4m)(SATIF-10)PHITS(4m)(SATIF-8)FLUKA(4m)(SATIF-10)HETC-3STEP(4m)(SATIF-8)ROZ-6.6(4m)(SATIF-8)MARS(4m)(SATIF-8)N
eutr
ons/
MeV
/cm
2 p
er n
/cm
2
Neutron Energy (MeV)
0
50
100
150
0 50 100 150
Fig. 12 Comparison of the neutron attenuation length of concretefor secondary neutrons from a Hg target with 3 GeV protons.
HETC(3GeV)(SATIF-8)GEANT-4(3GeV)(SATIF-10)ANISN(3GeV,6m,SATIF-6)ROZ-6.6(3GeV)(SATIF-8)PHITS(3GeV)(SATIF-8)MARS(3GeV)(SATIF-8)FLUKA(3GeV)(SATIF-10)GEANT-321(3GeV)(SATIF-8)ISIS Exp.(800MeV)
Att
en
uat
ion
Len
gth
of
Co
ncr
ete
(g c
m-2
)
Emission Angle (degree)
0
50
100
150
200
0 50 100 150
HETC-3STEP(3GeV,SATIF-6)GEANT-4(3GeV)(SATIF-10)ANISN(3GeV,SATIF-6)ROZ-6.6(3GeV)(SATIF-8)PHITS(3GeV)(SATIF-8)MARS(3GeV)(SATIF-8)FLUKA(3GeV)(SATIF-10)GEANT-321(3GeV)(SATIF-8)ISIS Exp.(800MeV)LANSCE Exp.(800MeV)A
tte
nu
atio
n L
eng
th o
f Ir
on
(g
cm
-2)
Fig. 11 Comparison of the neutron attenuation of iron for secondary neutrons from a Hg target with 3 GeV protons.
Emission angle (degrees)
Attenuation Length for Secondary Neutrons from Hg Target
General Tendencies are same with at SATIF-9. In the case of iron, all results show similar weak
dependence on the emission angle but their values are largely scattered between each other.
In the case of concrete, all results show stronger dependence on the emission angle than in the case of iron and a different dependence between the code used.
0
20
40
60
80
100
120
140
100 1000 104
Fig. 14 Comparison of the neutron attenuation length of concrete for secondary neutronsemiited to 90 degrees from Fe and Hg (24 GeV) target with protons.
GEANT-4(SATIF-10)ANISN(6m,SATIF-6)HETC-3STEP(SATIF-8,10)PHITS(R=3m)(SATIF-8)FLUKA(SATIF-10)MARS(SATIF-8)GEANT-321(SATIF-8)ROZ-6.6(SATIF-8)ISIS Exp.
Atte
nuat
ion
Len
gth
(g
cm-2
)
Proton Energy (MeV)