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Forum: Processes Involving Optical Photons
Re: None Scintillation photons leaking through refelctive surface (Geertje)
Re: Feedback Re: Scintillation photons leaking through refelctive surface (Gumplinger Peter)
Re: Feedback Re: Scintillation photons leaking through refelctive surface (Geertje)
Date: 30 Apr, 2014
From: Gumplinger Peter <Gumplinger Peter>

Dear Geertje,

> No RINDEX is set for the world material nor the foil, so there shouldn't
> be any - but I checked for Cerenkov photons in SteppingVerbose berfore,
> as I tought the same, but didn't find any. I also ran
> boundary->DumpInfo() and boundary->SetVerboseLevel(4) before but the
> optical photon just seems to miraculously appear in the foil_physic.

Yes, I can see that in your output.

> > For good measure also set:
> > 
> > /optics_engine/selectOpProcess Cerenkov /optics_engine/setOpProcessUse
> > false
> 
> Somehow, this doesn't work, I'm not sure why. It says: illegal
> application state -- command refused. I tried: False and 0, but it
> didn't work either

You need to set this before /run/initialize (but this can be hard to do if you have runManager->Initialize() in your main)

What I do not understand is this:

* G4Track Information:   Particle = e-,   Track ID = 1,   Parent ID = 0
    6   45.9 ps     11 um    108 um    3.7 cm      0 eV      0 eV      0 fm    1.3 cm   plScin_physic  Scintillation

and then:

* G4Track Information:   Particle = opticalphoton,   Track ID = 9509,   Parent ID = 1
    0   4.15 ns     11 um    108 um    3.7 cm   2.94 eV      0 eV      0 fm      0 fm   foil_physic    initStep

We don't have enough precision (on the 3.7cm z-coordinate) to understand why:

11 um 108 um 3.7 cm

gives in one case plScin_physic and in the other foil_physic.

The easiest is probably add a G4cout in SteppingAction on the z-coordinate of the step with greater precision than 0.1cm.

Yours is perhaps a geometry problem (but your geom-definition is correct as far as I can tell). Do you have access to the G4 source. If so, you can change in G4Scintillation.cc:

                aSecondaryTrack->SetTouchableHandle(
                                 aStep.GetPreStepPoint()->GetTouchableHandle());

to

                aSecondaryTrack->SetTouchableHandle((G4VTouchable*)0);

What happens?

Peter

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1 Ok: Re: Scintillation photons leaking through refelctive surface   (Geertje - 01 May, 2014)
(_ Feedback: Re: Scintillation photons leaking through refelctive surface   (Gumplinger Peter - 01 May, 2014)
(_ Question: Re: Scintillation photons leaking through refelctive surface   (Geertje - 01 May, 2014)
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