|Message: Re: Bertini Model cross section tables||Not Logged In (login)|
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On Wed, 28 Mar 2012 15:30:35 GMT, Juan Pablo Velasquez wrote:
> I would like to vary those cross sections values used by Bertini model > for estimating the mean free path inside the nucleus > (G4BertiniNucleiModel::ApplyYourself()).
That is actually G4CascadeInterface::ApplyYourself(). Don't get me started about the class names...
> Where are these tables taken > from (related classes, their references and corresponding errors)? It > isn't clear for me, which the main class is for handling cross section > values in the Bertini model.
Hello, Juan. We do not have any public interface to allow users to do this. If you can describe more about what you're interested in doing, we might be able to give you some guidance (or even rope you into doing some development work for us! :-) ).
The tables within the Bertini model just have values not errors, and they are complex multidimensional arrays in bins of kinetic energy, multiplicity, and individual final states. If you're looking at the source code, you can see all of these tables, in their unreadable detail, in G4Cascade*Channel.cc.
The place where the overall (total) cross-section is used to compute a mean free path is G4NucleiModel::generateInteractionPartners(). That function uses the MFP to decide (via random throw) whether the currently propagating cascade secondary interacts with a nucleon (or dibaryon in the case of pions).
If an interaction is possible (if the random path thrown is less than the "thickness" of the current nuclear potential zone), then G4ElementaryParticleCollider::collide() chooses which individual final state will be generated according to the cross-section tables.
-- Michael Kelsey