SetProductionCut usage

Physics Processes, Models and Cross Sections
1

We are simulating an experiment to calculate the net charging of a gold volume subjected to the flux of cosmic rays (mainly protons and electrons at an average energy of ~1 GeV). Given the task, it is crucial to estimate correctly the contribution of ionization electrons produced by primaries in the gold volume. We are using the StandardEM_opt4 electromagnetic physics, and to activate the simulation of ionization electrons we are reducing the standard production threshold to a much smaller value than the standard (0.7mm) using this lines:

G4Region* Inner = new G4Region(“INNER”);
Inner->AddRootLogicalVolume(fLogicTarget);
Inner->AddRootLogicalVolume(Shell4LV);
G4ProductionCuts * cuts2 = new G4ProductionCuts;
cuts2->SetProductionCut(15um,G4ProductionCuts::GetIndex(“gamma”));
cuts2->SetProductionCut(15um,G4ProductionCuts::GetIndex(“e-”));
cuts2->SetProductionCut(15um,G4ProductionCuts::GetIndex(“e+”));
cuts2->SetProductionCut(15um,G4ProductionCuts::GetIndex(“proton”));
Inner->SetProductionCuts(cuts2);

We are wondering if this is sufficient and if this is correct. Is there any limit under which is not safe to lower this threshold (for example due to some divergence in the electron production cross section or the limit to 790 eV in electron production from proton)?

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2

Hi,

the lines of code look good by a software point of view. I suppose you chose a cut which is smaller than the smallest size of the sensitive volume. Down to which energy you would like to track secondary electrons? My impression is that below 790 eV there will not be secondary electrons generated by protons. Did you test that?
In general, my suggestion is to do some tests where you retrieve the secondary particle spectra generated in the SV from different processes and cuts and you choose the cuts and low energy limit appropriate for your case.
I hope this helps,
Susanna