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Forum: Hadronic Processes
Re: None photonuclear reaction+isotope production cross section (Eleni)
Re: None Re: photonuclear reaction+isotope production cross section (Daren Sawkey)
Re: None Re: photonuclear reaction+isotope production cross section (Eleni)
Re: None Re: photonuclear reaction+isotope production cross section (Daren Sawkey)
Re: None Re: photonuclear reaction+isotope production cross section (Eleni)
Date: 22 Oct, 2015
From: Daren Sawkey <Daren Sawkey>

Results with version 10.0.0, with and without the photonuclear bugfix, are below. The number of photonuclear interactions is the same (within statistical precision), but with the fix all of the interactions produce neutrons.

Interestingly in your run there were twice as many photonuclear interactions. I don't know why--everything looks the same. My hand calculation gives 3300, in agreement with my Geant4 results. I attach my macro.

**********************************************************************************
unpatched
**********************************************************************************
 The run is 1000000 gamma of 13.5 MeV through 1 mm  of Au197 (density: 19.3 g/cm3 )

 Process calls frequency:
        Transportation= 996855  photonNuclear= 3145

 Nb of incident particles surviving after 1 mm  of Au197 : 996855

 MeanFreePath:  498.19 um  +- 288.42 um         massic: 961.51 mg/cm2
 CrossSection:  20.073 cm^-1            massic: 1.04 cm2/g
 crossSection per atom: 340.16 barn

 Verification: crossSections from G4HadronicProcessStore:
      Transportation= 0 um2/mg  0 pbarn
       photonNuclear= 173 um2/mg        565.82 mbarn
               total= 173 um2/mg        565.82 mbarn

 List of nuclear reactions:

                   gamma + Au197 --> N gamma + Au197:    2138   Q = -37.929 keV
         gamma + Au197 --> N gamma + neutron + Au196:    1007   Q = -8.1106 MeV

                                     Number of gamma: N = 1 --> 8

 List of generated particles:
          Au196:    1007  Emean =    4.84 keV   ( 11.699 eV  --> 32.278 keV)
          Au197:    2138  Emean =  1.0261 keV   ( 55.192 eV  --> 1.9445 keV)
          gamma:   11142  Emean =  2.9926 MeV   ( 31.699 keV --> 12.496 MeV)
        neutron:    1007  Emean =  852.41 keV   ( 1.8659 keV --> 5.0467 MeV)

   Momentum balance: Pmean = 0.059875 eV        ( 2.3617e-07 eV  --> 0.98338 eV )

**********************************************************************************
patched
**********************************************************************************
 The run is 1000000 gamma of 13.5 MeV through 1 mm  of Au197 (density: 19.3 g/cm3 )

 Process calls frequency:
        Transportation= 996716  photonNuclear= 3284

 Nb of incident particles surviving after 1 mm  of Au197 : 996716

 MeanFreePath:  498.08 um  +- 290.78 um         massic: 961.29 mg/cm2
 CrossSection:  20.077 cm^-1            massic: 1.0403 cm2/g
 crossSection per atom: 340.24 barn

 Verification: crossSections from G4HadronicProcessStore:
      Transportation= 0 um2/mg  0 pbarn
       photonNuclear= 173 um2/mg        565.82 mbarn
               total= 173 um2/mg        565.82 mbarn

 List of nuclear reactions:

         gamma + Au197 --> N gamma + neutron + Au196:    3280   Q = -8.1099 MeV
                          gamma + Au197 --> gamma + :       2   Q =       0 eV
                   gamma + Au197 --> neutron + Au196:       2   Q = -8.1248 MeV

                                     Number of gamma: N = 1 --> 7

 List of generated particles:
          Au196:    3282  Emean =  5.0657 keV   ( 11.699 eV  --> 32.278 keV)
          gamma:   11688  Emean =  1.2628 MeV   ( 9.8907 keV --> 5.0843 MeV)
        neutron:    3282  Emean =   887.8 keV   ( 246.43 eV  --> 5.393 MeV)

   Momentum balance: Pmean = 0.046732 eV        ( 8.2661e-10 eV  --> 1.3114 eV )

   Attachment:
      http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2015/10/22/16.48-40935-photonuclear.mac

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