In(n,n')In115m reactions in Hadr03


I am simulating the In115(n,n’)In115m reaction with neutrons having energies ranging from 0.5 MeV to 20 MeV. My target is a 1 cm-thick layer of natural indium (material G4_In) and I started with monoenergetic neutrons in the Hadr03 example. I have encountered 2 main issues so far :

  • First of all, when I use the (QGSP_BIC or QGSP_INCLXX) + (_HP or _AllHP) PhysicsLists there is NO metastable state produced at all. When the neutron energy exceeds 20 MeV I finally get some metastable states because the _HP model gives up and the BIC/INCLXX model takes over but beyond 20 MeV is out of the energy range I require. My guess is that something is wrong with the G4NDL4.7 neutron inelastic data but I cannot understand what. How come no metastable state is being tracked with the high precision G4NDL data ?

  • Next, when I only use the (QGSP_BIC or QGSP_INCLXX) PhysicsLists, I can get some In115m. Yet for energies below 1.5 MeV and 1 MeV respectively, I get ZERO metastable states although the cross-section is non zero at these energies, no matter how many neutrons I use in my simulation. I think this is linked to the energy range of the PhysicsLists which start at 1.5 MeV for QGSP_BIC and 1 MeV for QGSP_INCLXX but I absolutely need to know my metastable state production between 0.5 MeV and 1.5 MeV. How can I account for In(n,n’)In115m reactions at energies lower than 1 MeV ?

Thank you for your time,

_Geant4 Version:_11.2.0
_Operating System:_Red Hat 8.5.0-18
_CMake Version:_3.20.2