Cosmic Ray activation ofGermanium in Geant4

Janicsko Jozsef

LNGS Nov.2007,JJ

Introduction

• Since the release of geant4.9.0 is possible to simulate materialswith different isotopic composition, the default behaivior of G4,is to identify elements based on A and Z

• Available data incomplete ...

• Several theory driven physics models available in G4 as well

• Geant4 is a general purpose MC, all detector simulations arebased on, would be nice to do all in one MC

• My baseline for comparison: I. Barabanov et al., NIM B 251(2006) 115-120 (and the simmilar internal note)

LNGS Nov.2007,JJ 1/11

68Ge

• First try with the Bertini-cascade: Production cross section of68Ge by neutrons on different Ge isotopes

• It works ...

SHIELD code Geant4

E [MeV]210 310

X s

ecti

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[m

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-210

-110

1

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Production X section of Ge68 by neutrons on diff. targets ’QGSP_BERT_HP’

Ge76Ge74Ge73Ge72Ge70

LNGS Nov.2007,JJ 2/11

• Protons are a bit different. Don’t get excited, the flux of cosmicprotons is a few order of magnitudes smaller (than of theneutrons) in the relevant energy range

SHIELD code Geant4

E [MeV]210 310

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-210

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Production X section of Ge68 by protons on diff. targets ’QGSP_BERT_HP’

Ge76Ge74Ge73Ge72Ge70

LNGS Nov.2007,JJ 3/11

60Co

SHIELD code Geant4

E [MeV]210 310

X s

ecti

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[m

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-110

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Production X section of Co60 by neutrons on diff. targets ’QGSP_BERT_HP’

Ge76Ge74Ge73Ge72Ge70

LNGS Nov.2007,JJ 4/11

Comparison of different models

• I tried out all relevant models in Geant4.

E [MeV]210 310

X s

ecti

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[m

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Production X section of Ge68 by protons in natural Ge

QGSP_BERT_HP

QGSP_BIC_HPQBEC_HP

QBBC_HP LHEP_BERT

LHEP_PRECO_HP

QBBC

QBBCGQBECQGSP_BERTQGSP_BERT_NQE

QGSP_BERT_TRVQGSP_BIC

Horiguchi ’83

E [MeV]210 310

X s

ecti

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[m

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-110

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Production X section of Ge68 by neutrons in natural Ge

QGSP_BERT_HP

QGSP_BIC_HPQBEC_HP

QBBC_HP LHEP_BERT

LHEP_PRECO_HP

QBBC

QBBCGQBECQGSP_BERTQGSP_BERT_NQE

QGSP_BERT_TRVQGSP_BIC

Horiguchi ’83

LNGS Nov.2007,JJ 5/11

60Co

E [MeV]210 310

X s

ecti

on

[m

bar

n]

-210

-110

1

10

Production X section of Co60 by protons in natural Ge

QGSP_BERT_HP QGSP_BIC_HPQBEC_HP QBBC_HP LHEP_BERTLHEP_PRECO_HPQBBCQBBCGQBECQGSP_BERTQGSP_BERT_NQEQGSP_BERT_TRVQGSP_BICNorman ’05

E [MeV]210 310

X s

ecti

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[m

bar

n]

-210

-110

1

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Production X section of Co60 by neutrons in natural Ge

QGSP_BERT_HP QGSP_BIC_HPQBEC_HP QBBC_HP LHEP_BERTLHEP_PRECO_HPQBBCQBBCGQBECQGSP_BERTQGSP_BERT_NQEQGSP_BERT_TRVQGSP_BIC

Conclusion: BERT is OK for 68Ge (and below 1 GeV), BIC(BinaryCascadeModel) better for 60Co and in general, above 1GeV

LNGS Nov.2007,JJ 6/11

Comparison with other MC

• See: H. Gomez et al. arXiv:0708.3987v1 nucl-ex, IDEA reportetc.

E [MeV]210 310

X s

ecti

on

[m

bar

n]

-110

1

10

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Production X section of Ge68 by neutrons in natural Ge

QGSP_BERT_HP

QGSP_BIC_HPQBEC_HP

QBBC_HP LHEP_BERT

LHEP_PRECO_HP

QBBC

QBBCGQBECQGSP_BERTQGSP_BERT_NQE

QGSP_BERT_TRVQGSP_BIC

Horiguchi ’83

1

10

100

1000

10 100 1000 10000energy (MeV)

pro

du

ctio

n c

ross s

ectio

n (

mb

)

YIELDX (Silberberg&Tsao) Aleksandrov'91 MENDL-2P (p)

MENDL-2 (n) Horiguchi'83 ISABEL (Majorana, n)

CEM95 (p) HMS-ALICE (p) HMS-ALICE (n)

LNGS Nov.2007,JJ 7/11

Comparison with other MC 2.

E [MeV]210 310

X s

ecti

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[m

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-110

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Production X section of Co60 by neutrons in natural Ge

QGSP_BERT_HP QGSP_BIC_HPQBEC_HP QBBC_HP LHEP_BERTLHEP_PRECO_HPQBBCQBBCGQBECQGSP_BERTQGSP_BERT_NQEQGSP_BERT_TRVQGSP_BIC

0,001

0,010

0,100

1,000

10,000

10 100 1000 10000energy (MeV)

pro

duction c

ross s

ection (

mb)

YIELDX (Silberberg &Tsao) Aleksandrov'91 Norman'05

MENDL-2P (p) MENDL-2 (n) CEM95 (p)

HMS-ALICE (p) HMS-ALICE (n)

Conclusion: Geant4 in principle can reproduce these plots (andaccomodate all data points). Hybrid physics list shows strangebehaivior, under investigation ...

LNGS Nov.2007,JJ 8/11

Cosmic nucleons

E [MeV]10 210 310 410

Flu

x []

-1110

-1010

-910

-810

-710

-610

-510

-410

• Flux of neutrons and protons dropsfast above 1 GeV.

• One order of magnitude differencesbetween MC codes might besupressed by larger variations of thecosmic ray flux

nat Ge enr Ge68Ge 60Co 68Ge 60Co

QGSP BERT HP 105.01 1.09 14.48 1.03QGSP BIC HP 14.37 5.1 0.19 2.33

Total production rates computed with the isotopic abundance ofnat. and enr. Ge (/kg/day)

LNGS Nov.2007,JJ 9/11

Summary

nat Ge enr Ge68Ge 60Co 68Ge 60Co

G4 105.01 5.1 14.48 2.33Shield 83.92 2.86 5.8 3.31Ref.[1] 89 4.8 13 6.7

MC Ref.[2] 29.6 - 0.94 -Data Ref.[2] 30+-7 - - -

Summary of all known estimates (/kg/day)

[1] H. Gomez et al. arXiv:0708.3987v1 nucl-ex

[2] F.T. Avignone et al., Nucl.Phys.B (Proc Suppl.)28A,1992

LNGS Nov.2007,JJ 10/11

Conlusion

• Despite some discrepancies, Geant4 agrees with other MCcodes within the error (uncertenity) of those

• In principle Geant4 can be tuned to reproduce the data pointsshown in H. Gomez et al. arXiv:0708.3987v1 nucl-ex

• You can use it with the predefined physics lists if you know whatare you doing

• Is impossible to accomodate the data of Horiguchi’83 andAvignone’92 in the same estimate. Choose one, (G4 can doboth)

LNGS Nov.2007,JJ 11/11