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Idea Re: can geant4 cosider optical processes and atomic relaxation simultaneously? 

Forum: Processes Involving Optical Photons
Re: None can geant4 cosider optical processes and atomic relaxation simultaneously? (Mahdi)
Date: 12 Nov, 2013
From: Gumplinger Peter <Gumplinger Peter>

Hi Mahdi,

x-rays that are generated by G4 deexitation processes and fluorescence are not considered to be 'optical photons'. The are considered to be G4Gamma particles.

I have not done this - come to think of it - there is nothing that should prevent you from adding 'optical physics processes' to G4Gamma particles in Geant4; specifically the G4OpBoundaryProcess. Now, you have to provide the index of refraction of the media of your optical lenses in the energy range of the x-rays. Similarly, you have to provide 'optical absorption length' for your optical filter. Alternatively, I believe in your UserStackingAction, you may be able to change the particle type of the secondary track object from G4Gamma to G4OpticalPhoton, though that's not so easy because for:

ClassifyNewTrack(const G4Track* aTrack);

you are passed a const pointer.

The problem with my first suggestion is that the G4OpBoundaryProcess:

http://www-geant4.kek.jp/lxr/source/processes/optical/include/G4OpBoundaryProcess.hh#L261

IsApplicable method needs to be modified to allow for a G4Gamma to have optical processes (and similarly for all the other Op-Processes that you may require). For that you'd need your own G4 source and library.

Another avenue that should work perhaps without any tricks of stripping const from a pointer and modifying the G4 source, is to device a new (user) process that has a zero range for x-rays and does nothing else but transform a G4Gamma to a G4OpticalPhoton. For that you have to learn how to add a user-process in G4:

http://geant4.slac.stanford.edu/UsersWorkshop/G4Lectures/Marc/

AddingNewProcess.PPT

Peter

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1 None: Re: can geant4 cosider optical processes and atomic relaxation simultaneously?   (Mahdi - 12 Nov, 2013)
(_ Idea: Re: can geant4 cosider optical processes and atomic relaxation simultaneously?   (Gumplinger Peter - 12 Nov, 2013)
(_ None: Re: can geant4 cosider optical processes and atomic relaxation simultaneously?   (Mahdi - 13 Nov, 2013)
(_ Feedback: Re: can geant4 cosider optical processes and atomic relaxation simultaneously?   (Gumplinger Peter - 13 Nov, 2013)
(_ Sad: Re: can geant4 cosider optical processes and atomic relaxation simultaneously?   (Mahdi - 13 Nov, 2013)
(_ Feedback: Re: can geant4 cosider optical processes and atomic relaxation simultaneously?   (Gumplinger Peter - 14 Nov, 2013)
(_ Ok: Re: can geant4 cosider optical processes and atomic relaxation simultaneously?   (Mahdi - 15 Nov, 2013)
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