Hi,

I am simulating a Thorium Oxide (ThO2) target, bombarded with 1 GeV protons and the QGSP_BIC_HP physics list. Now, there must be no fission going on, since Thorium does not undergo fission, and there is no fission data in G4NDL3.13. This happens with NO Thorium data in G4NDL AND $G4NEUTRONHP_SKIP_MISSING_ISOTOPES = 1. However in my simulation I get strange results:

**********************************************************************************
* G4Track Information:   Particle = neutron,   Track ID = 3350,   Parent ID = 3181
**********************************************************************************

Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    0   2.75 mm   2.59 mm   38.8 cm   54.7 MeV     0 eV      0 fm      0 fm       target    initStep
    1   2.83 mm  -3.43 mm   38.6 cm   54.7 MeV  6.62 keV  6.29 mm   6.29 mm       target    hElastic
    2   1.15 mm  -1.41 cm   38.3 cm      0 eV      0 eV   1.12 cm   1.75 cm       target    nFission
"cout message :Fission takes place at t = 0 s"

Please note that the neutron energy dropped to zero despite a dEstep of only 6.62 keV....

Or similar:

********************************************************************************
* G4Track Information:   Particle = neutron,   Track ID = 5053,   Parent ID = 94
********************************************************************************

Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    0  -9.75 mm  -1.97 mm   19.6 cm    147 MeV     0 eV      0 fm      0 fm       target    initStep
    1    2.7 cm   7.79 mm   16.4 cm    147 MeV  34.5 keV  4.98 cm   4.98 cm       target    hElastic
    2   9.68 cm   1.96 cm   12.6 cm      0 eV      0 eV   8.03 cm     13 cm       target    nFission

With the same sudden drop to 0 eV, with no dE justifying it,

Or,

********************************************************************************
* G4Track Information:   Particle = neutron,   Track ID = 21183,   Parent ID = 21085
********************************************************************************

Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    0   7.63 cm  -5.85 mm   15.6 cm     38 MeV     0 eV      0 fm      0 fm       target    initStep
    1    8.7 cm   1.21 mm     14 cm     38 MeV  4.27 keV  2.05 cm   2.05 cm       target    hElastic
    2     11 cm   2.53 cm   10.3 cm      0 eV      0 eV   4.94 cm      7 cm       target    nFission

There is always this sudden drop to 0 eV, followed by fission which should not take place. I believe that because the neutron energy becomes strictly zero, the $G4NEUTRONHP_SKIP_MISSING_ISOTOPES = 1 resulting in:

NeutronHP: /Fission file for Z = 90, A = 232 is not found and CrossSection set to 0.

has no effect...

I attached the large /tracking/verbose 1 output file.

Best regards,

Cristian