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Question Questions about QBBC Physics List 

Forum: Physics List
Date: 12 Dec, 2014
From: Zach Miller <Zach Miller>


I have some questions about some strange results I'm getting from the QBBC Physics List. I've set up a routine that reads out the cross-sections for Hadronic interactions in my program. It looks like this and is borrowed from example/Hadr03:

 std::map<const G4VProcess*,G4int>::iterator it;    
 for (it = fProcCounter.begin(); it != fProcCounter.end(); it++) {
    const G4VProcess* process = it->first; 
    G4String procName = it->first->GetProcessName();
    if(procName == "hadElastic"){
      G4cout << "\t" << procName << "\n";
      for(G4double i = 1; i <= 20; i+=0.1)
	  G4double en = i*MeV;
	  G4cout << i << " " << G4BestUnit(dataStore->GetCrossSectionPerVolume(particle,en,process,material)/density,"Surface") << "\n";

I'm getting some strange results, which I will attach some plots of.

1) My results are higher than the ENDF tabulations by a constant factor... but that factor is different for each material. The legend in the plots shows how I'm having to scale each result to bring it onto scale with ENDF results. So, in the npElastic plot I've attached, I must divide the GEANT result by 100, and then it matches perfectly with ENDF. For Carbon, I must divide by 8.33, and then it will match (except for concern 2). Why are there these factors that are coming out? I'm getting the right energy dependence, but the wrong overall normalization. Is this in the QBBC List, or is dividing by the density not enough to give me the correct result?

2) For Carbon elastic, it looks like the QBBC list is averaging over the resonances to just get the "general" behaviour. If I use FTFP_BERT_HP, I get exactly the right cross-section for nC, resonances and all. Is there a way to restore the full nC cross-section in QBBC? If not, is there a way to make the averaging function have a smaller bin width so that I have a higher resolution to changes in the cross-section? In my result, it looks like the QBBC nC-Elastic is binned into 2 MeV averages, I need it to be binned on the order of a 100-200 keV, if it's going to be averaged like this.

Thanks for any and all help, Zach


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1 More: Re: Questions about QBBC Physics List   (Zach Miller - 12 Dec, 2014)
(_ None: Re: Questions about QBBC Physics List   (michel maire - 12 Dec, 2014)
(_ Feedback: Re: Questions about QBBC Physics List   (Zach Miller - 15 Dec, 2014)
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