Problem 1054

Hi,

    What version of Geant4 are you using?

Also, what is the size of the energy non-conservation?   For such data-driven
models as neutronHP, there will always be a very small amount due to finite
size bins in the look-up tables.

Dennis

Seems that neutron inelastic processes in liquid argon still have some issues.  The following is an example by using latest Geant4.9.3 with G4NDL3.13

*********************************************************************************************************
* G4Track Information:   Particle = neutron,   Track ID = 1,   Parent ID = 0
*********************************************************************************************************

Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    0   50.4 cm  -18.1 cm   28.6 cm   8.01 MeV     0 eV      0 fm      0 fm          PMT    initStep
    1   49.6 cm  -18.6 cm   28.1 cm   8.01 MeV     0 eV   1.05 cm   1.05 cm          PMT  Transportation
    2   37.4 cm  -27.2 cm   20.6 cm      0 eV      0 eV   16.8 cm   17.8 cm   InnerVacuum  NeutronInelastic
    :----- List of 2ndaries - #SpawnInStep=  4(Rest= 0,Along= 0,Post= 4), #SpawnTotal=  4 ---------------
    :   37.4 cm  -27.2 cm   20.6 cm   11.5 MeV   neutron
    :   37.4 cm  -27.2 cm   20.6 cm    470 keV Ar40[0.0]
    :   37.4 cm  -27.2 cm   20.6 cm   1.46 MeV     gamma
    :   37.4 cm  -27.2 cm   20.6 cm    717 eV      gamma
    :----------------------------------------------------------------- EndOf2ndaries Info ---------------

from which you can see a neutron with energy 8.01 MeV undergo (n,n')Ar40  inelastic process and give you a 11.5MeV outgoing neutron with recoil and excitation gamma rays. Firstly, the energy is not conserved by excess of 67.7%. Secondly, this 717 eV gamma ray looks to me does not make sense because there is no any excitation gamma ray line or transition X-ray line can match it. I am wonder if this relates to the process code bug or data base issue. Is there any body give an explanation?
Thanks!

(In reply to comment #2)

I just realized that all those energy non-conservation vertex happened at the boundary from PMT to liquid argon volume. And the NeutronInelastic process happend to be the first interaction process in the liquid argon volume. For example (another vertex)  

*********************************************************************************************************
* G4Track Information:   Particle = neutron,   Track ID = 1,   Parent ID = 0
*********************************************************************************************************

Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    1   58.9 cm  -3.89 cm  -12.1 cm    6.1 MeV     0 eV      0 fm    1.2 cm          PMT    initStep
    2   58.7 cm  -4.15 cm  -11.8 cm    6.1 MeV     0 eV   4.41 mm   1.64 cm          PMT  Transportation
    3   57.1 cm  -6.13 cm  -9.62 cm      0 eV      0 eV   3.35 cm      5 cm   InnerVacuum  NeutronInelastic
    :----- List of 2ndaries - #SpawnInStep=  4(Rest= 0,Along= 0,Post= 4), #SpawnTotal=  4 ---------------
    :   57.1 cm  -6.13 cm  -9.62 cm   11.3 MeV   neutron
    :   57.1 cm  -6.13 cm  -9.62 cm    622 keV Ar40[0.0]
    :   57.1 cm  -6.13 cm  -9.62 cm   1.46 MeV     gamma
    :   57.1 cm  -6.13 cm  -9.62 cm   1.26 keV     gamma
    :----------------------------------------------------------------- EndOf2ndaries Info ---------------

But that does not mean all the similar NeutronInelastic processes have energy conservation issue although those excitation gamma ray lines are still messed up. For example:
*********************************************************************************************************
* G4Track Information:   Particle = neutron,   Track ID = 1,   Parent ID = 0
*********************************************************************************************************

Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    0   24.8 cm     16 cm  -52.6 cm   3.51 MeV     0 eV      0 fm      0 fm          PMT    initStep
    1   24.7 cm   15.9 cm  -52.3 cm   3.51 MeV     0 eV   3.41 mm   3.41 mm          PMT  Transportation
    2   24.1 cm   15.6 cm  -48.9 cm      0 eV      0 eV   3.47 cm   3.81 cm   InnerVacuum  NeutronInelastic
    :----- List of 2ndaries - #SpawnInStep=  5(Rest= 0,Along= 0,Post= 5), #SpawnTotal=  5 ---------------
    :   24.1 cm   15.6 cm  -48.9 cm    982 keV   neutron
    :   24.1 cm   15.6 cm  -48.9 cm    121 keV Ar40[0.0]
    :   24.1 cm   15.6 cm  -48.9 cm   1.34 MeV     gamma
    :   24.1 cm   15.6 cm  -48.9 cm   1.06 MeV     gamma
    :   24.1 cm   15.6 cm  -48.9 cm    935 eV      gamma
    :----------------------------------------------------------------- EndOf2ndaries Info ---------------

Those inelastic vertex in the middle of argon seem fine with energy conservation(gamma rays are wrong). For the materials and boundaries, I did not define any properties for them. The following is the definition of PMTs:

 G4Material *fglass=new G4Material("fglass",density=2.0*g/cm3, ncomponents=8);
 fglass->AddElement(O,fractionmass=0.557);
 fglass->AddElement(Si,fractionmass=0.347);
 fglass->AddElement(Ca,fractionmass=0.3580000E-02);
 fglass->AddElement(Al,fractionmass=0.1590000E-02);
 fglass->AddElement(B,fractionmass=0.6840000E-01);
 fglass->AddElement(Na,fractionmass=0.7420000E-02);
 fglass->AddElement(K,fractionmass=0.1250000E-01);
 fglass->AddElement(Li,fractionmass=0.2320000E-02);
 
and for argon:

G4Element* Ar  = new G4Element("Argon",symbol="Ar" , z= 18., a= 39.95*g/mole);
G4Material* liquidArgon =
  new G4Material("liquidArgon", density= 1.39*g/cm3, ncomponents=1);
  liquidArgon->AddElement(Ar, natoms=1);

I hope that will helps to identify the issues. 

Thanks,
Chao

Hi

These very low photons are artificially emitted for better energy and momentum conservations.
So if you do not want to this treatment, then please set the environment variable of "G4NEUTRONHP_DO_NOT_ADJUST_FINAL_STATE".
Then those photons should disappear. 

Tatsumi