The answer to the original question is to investigate LEND. In Hadr03 PhysicsList.cc, use
RegisterPhysics(new G4EmExtraPhysics())
and remove the others. Otherwise LEND looks to be part of the main physics lists like QGSP_BIC etc.
Download the files and set G4LENDDATA envvar.
In the macro set
/physics_lists/em/LENDGammaNuclear true
Results look reasonable (nearly all interactions produce >= 1 neutron, but I haven’t looked up the expected values).
The run is 100000 gamma of 15 MeV through 100 m of G4_W (density: 19.3 g/cm3 )
Process calls frequency:
photonNuclear= 100000
MeanFreePath: 38.911 cm ± 38.831 cm massic: 750.98 g/cm2
CrossSection: 0.0257 cm^-1 massic: 133.16 um2/mg
crossSection per atom: 406.5 mbarn
Verification: crossSections from G4HadronicProcessStore:
photonNuclear= 133.64 um2/mg 407.99 mbarn
total= 133.64 um2/mg 407.99 mbarn
List of nuclear reactions:
gamma + W180 --> N gamma or e- + W180: 1 Q = 0.013293 eV
gamma + W180 --> neutron + W179: 123 Q = -13.545 MeV
gamma + W182 --> 2 neutron + W180: 638 Q = -14.787 MeV
gamma + W182 --> N gamma or e- + W182: 184 Q = 0.0056906 eV
gamma + W182 --> neutron + W181: 25936 Q = -13.552 MeV
gamma + W183 --> 2 neutron + W181: 926 Q = -14.527 MeV
gamma + W183 --> N gamma or e- + W183: 42 Q = 0.0017366 eV
gamma + W183 --> neutron + W182: 13700 Q = -13.068 MeV
gamma + W184 --> N gamma or e- + 2 neutron + W182: 9586 Q = -8.5215 MeV
gamma + W184 --> N gamma or e- + 2 neutron + W183: 5644 Q = -8.9998 MeV
gamma + W184 --> N gamma or e- + neutron + W183: 14564 Q = -10.583 MeV
gamma + W184 --> N gamma or e- + proton + neutron + W183: 1 Q = -3.5572 MeV
gamma + W186 --> 2 neutron + W184: 19646 Q = -13.391 MeV
gamma + W186 --> N gamma or e- + W186: 42 Q = 0.0014322 eV
gamma + W186 --> neutron + W185: 8967 Q = -11.665 MeV
number of gamma or e- (ic): N = 2 --> 16
List of generated particles:
W179: 123 Emean = 8.8966 keV ( 557.04 eV --> 31.703 keV)
W180: 639 Emean = 1.9281 keV ( 35.52 eV --> 7.4462 keV)
W181: 26862 Emean = 8.5172 keV ( 8.2666 eV --> 39.994 keV)
W182: 23470 Emean = 11.189 keV ( 2.4015 eV --> 130.01 keV)
W183: 20251 Emean = 13.76 keV ( 0.0014155 eV --> 51.927 keV)
W184: 19646 Emean = 9.3703 keV ( 19.486 eV --> 44.554 keV)
W185: 8967 Emean = 18.74 keV ( 147.5 eV --> 43.913 keV)
W186: 42 Emean = 959.21 eV ( 58.98 eV --> 2.4659 keV)
e-: 428 Emean = 164.39 keV ( 18.476 keV --> 846.91 keV)
gamma: 82746 Emean = 1.0653 MeV ( 20.708 eV --> 14.874 MeV)
neutron: 136171 Emean = 1.4782 MeV ( 25.885 eV --> 18.27 MeV)
proton: 1 Emean = 5.7388 MeV ( 5.7388 MeV --> 5.7388 MeV)
but there are many warnings:
-------- WWWW ------- G4Exception-START -------- WWWW -------
*** G4Exception : had012
issued by : G4HadronicProcess:CheckResult()
Warning: Bad energy non-conservation detected, will re-sample the interaction
Process / Model: photonNuclear / LENDorBERTModel
Primary: gamma (22), E= 15, target nucleus (74, 184)
E(initial - final) = -169446 MeV.
*** This is just a warning message. ***
-------- WWWW -------- G4Exception-END --------- WWWW -------