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Forum: Processes Involving Optical Photons
Re: None Problem Counting Optical Photons (Zach Miller)
Date: 05 Aug, 2011
From: Gumplinger Peter <Gumplinger Peter>

Hi Zach,

In your main you construct objects of type UserSteppingAction, UserEventAction etc. It is these very objects you need pointers too if you want to cross communicate between them. It is not enough to simply declare an object of one action-type in a method of another action. This object is deleted when the method is exited and a new one wiped/empty/or garbage in memory is made the next time this method is invoced. Please, see the novice examples of how to provide pointers to the one and only object of an action class to another user action. (You should also reread some fundamental principles of C++)

Now, more specifically to Geant4 and optical photon tracking, I must warn you that when the preStepPoint is in medium1 and the postStepPoint is in medium2 that this coincidence does not mean that the photon will actually go 'into' medium2. Optical photons can be reflected. The way you count you'll get all of the reflections as well. An optical photon is in medium2 if the preStepPoint is in medium2. I should hope that in your optics it can only get into medium2 from medium1 and not some other way.

One way to make sure you don't count reflections and only photons coming through a particular window is to add a narrow window volume of material2 to your geometry. (you make this a daughter of the volume with material2) If a photon now crosses from the window volume into the remainder of material2 you should be fine counting the way you did.


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1 None: Re: Problem Counting Optical Photons   (Zach Miller - 09 Aug, 2011)
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