Hi All,
Im runnning a simple project looking at energy deposition of heavy ions (A>30) with energies 50-100 MeV in a gas (150mbar Isobutane). Im using EmStandard_option4. In geant4 this seems to be handeled by the class G4ionIonisation.
I printed stopping power curves from events in my project and there’s a clear change in model at a certain position on my de/dx curves. This discontinuity happens at different points/energies depending on the ion.
Looking through the physics list information and my beginners reading of the source code, there seems to be inconsistencies. Heres the standard Physics list readout:
ionIoni: for GenericIon XStype:3 SubType=2
dE/dx and range tables from 100 eV to 100 TeV in 240 bins
Lambda tables from threshold to 100 TeV, 20 bins/decade, spline: 1
StepFunction=(0.1, 0.001 mm), integ: 3, fluct: 1, linLossLim= 0.02
===== EM models for the G4Region DefaultRegionForTheWorld ======
LindhardSorensen : Emin= 0 eV Emax= 100 TeV deltaVI
My reading of the source code is that LindardSorensen simply isnt used in my case. G4BetheBlocModel is used above a threshold and G4BraggIonModel (which uses tabled data?) is used beneath it, this threshold should be 2MeV/MassNumber and I should basically never pass this threshold. Beneath 1MeV nuclear stopping should take over if I include the relevant physics lists.
Can anyone explain the G4ionIonisation class to me in more detail? Im particularly confused on threshold energies and which models act above and below these thresholds.
Thanks in advance!
Will
geant4-v11.2.1
Mac Sanoma 14.7.1
Apple clang version 16.0.0 (clang-1600.0.26.4)
cmake version 3.30.5