[Gate-users] Optical photon transport in Gate 6

Marcin Balcerzyk m.balcerzyk at pluri.ucm.es
Tue Dec 20 23:31:46 CET 2011

Dear Gaters.


I try to simulate optical photons in my scintillating PET detector. I first
tried to do EXAMPLE_optical enabling Hits and ascii output and "analysis on,
fastanalysis off" to have it more clear. 


My problem is to get an idea of how position sensitive photomultiplier or
SiPMT would see the photons coming from the crystal in the above example.
Namely at which position on the surface of the PMT the photon would end up.
When I visualize the hits in TreeViewer of root, I can see the photons only
inside the crystal and not "passing" to PMT, or through the respective
surface between pixel and PMT. Is anybody of  you doing anything similar, or
understand better the functioning of the optical photon transport? I use
vGate 1.0 (that is Gate 6.0 patch 1 in Ubuntu 9).


I looked at hits in this example, and it seems that after producing of
optical photons most of them do not propagate. In the interaction column of
hits.dat I see Transport or ObticalAbsorption. For each scintillating event,
there is a few thousands photons with numbers decreasing from say 1234 to 1
with some numbers missing. Then there is nothing more happening with each
photon. I am not sure if the lack of propagation is due to some settings of
the example, or improper setup of surface.xml properties. 


I would be obliged for some help and can continue discussion in direct


Marcin Balcerzyk,

Universidad de Sevilla,


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