Hello, I hope you are well! I’m fairly new to Geant4, so I hope my question isn’t too basic or confusing.
I’m using geant4.10.06.p01 to try and simulate neutrons using the GeneralParticleSource, but I have continuously ran into the following exception (currently using G4NDL4.6):
-------- EEEE ------- G4Exception-START -------- EEEE ------- *** G4Exception : had001 issued by : G4CrossSectionDataStore::GetIsoCrossSection No isotope cross section found for neutron off Element C in G4_AIR Z= 6 A= 12 E(MeV)= 21.256 *** Fatal Exception *** core dump *** G4Track (0x7f8432c30580) - track ID = 1, parent ID = 0 Particle type : neutron - creator process : not available Kinetic energy : 21.256 MeV - Momentum direction : (-0.994596,0.0521508,0.0897778) Step length : 0 fm - total energy deposit : 0 eV Pre-step point : (700,29.0184,-276.148) - Physical volume : WorldVol (G4_AIR) - defined by : not available Post-step point : (700,29.0184,-276.148) - Physical volume : WorldVol (G4_AIR) - defined by : not available *** Note: Step information might not be properly updated. -------- EEEE -------- G4Exception-END --------- EEEE -------
The element is not unique (I’ve also experienced this with, e.g., hydrogen, argon, copper, etc.). I noticed that this only occurs for kinetic energies above 20 MeV, so I assume that the cross section files don’t contain information above that energy (per a maximum kinetic energy check).
I have tried alternate neutron cross section libraries JEFF-3.3 and ENDF/B-VIII.0 (via https://www-nds.iaea.org/geant4/), but this hasn’t helped. Is there any way to work around this exception?
Thanks in advance!