Inter-comparison of Medium-Energy Neutron Attenuation in Iron and Concrete (8) H. Hirayama and Attenuation Length Sub-Working Group in Japan

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


0


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


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


Cal

c./ E

xpt.



0

0.5

1

1.5

2

0 50 100 150 200 250 300

209Bi(n,4n)206Bi24GeV, Steel


Cal

c./ E

xpt.


Range ofExperimental Error

0

0.5

1

1.5

2

0 50 100 150 200 250 300

209Bi(n,6n)204Bi24 GeV, Steel


Cal

c./ E

xpt.



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


Cal

c./ E

xpt.

Concrete Thickness (cm)


0

0.5

1

1.5

2

0 50 100 150 200 250 300 350 400

209Bi(n,6n)204Bi2.83 GeV, Concrete


Cal

c./ E

xpt.



0

0.5

1

1.5

2

0 50 100 150 200 250 300 350 400

209Bi(n,4n)206Bi24 GeV, Concrete


Cal

c./ E

xpt.



0

0.5

1

1.5

2

0 50 100 150 200 250 300 350 400

209Bi(n,6n)204Bi24 GeV, Concrete


Cal

c./ E

xpt.



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


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


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)

Documents

Inter-comparison of Medium-Energy Neutron Attenuation in Iron and Concrete (8) H. Hirayama and Attenuation Length Sub-Working Group in Japan