|Message: Re: Need to define some custom physics in Geant4 - how?||Not Logged In (login)|
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On Thu, 14 Aug 2014 09:25:18 GMT, Christopher Walker wrote:
> Hi Jack, > I am in a similar situation - requiring custom physics which is not in any physics list. You > talked about being on the right track due to the intervention of an expert. Can you enlighten > further, or put me in touch with this expert. I am looking at the examples as suggested by I. > Ivanchenko, but I presume it was not I. Ivanchenko who directly advised you as he responded to > your posting much later.
If you already have the physics itself written (in the form of subclasses of G4VProcess/G4VDiscreteProcess/etc.) then what you need to do is to use your own custom physics list, and attach your processes to the appropriate particles. As noted by Vladimir, we have multiple examples in both the hadronic and EM areas which demonstrate this.
If you haven't written the physics yet, you can still use those examples, and see how the custom processes are written. You may also want to look at the Toolkit Developer's Guide in our documentation area, which addresses some of this stuff better than the Application Developer's Guide.
If you are implement a physics _model_ -- that is, some specific parametrization of an already known "kind" of physics (bremsstrahlung, inelastic hadronic scattering, neutron capture, etc.) -- then you could consider writing a model class and registering that model with the existing G4 process. There have been postings in Hypernews discussing this in different contexts, but generally you'll need some close interaction with G4 developers to really get it right.
-- Michael Kelsey