[Gate-users] How to find the relation between different hits?

[Astrid Velroyen]

Dear GATE users,

I have got a question about how to analyze a GATE Hits simulation with 
.root-Output. I'd like to be able to identify which hits belong to the 
same incident gamma quantum. That means, that I want to keep track of of 
each photon and find out which way it has gone, if it has left energy in 
different crystals and so on.
I'm not sure which of the histogrammed data in the root output can 
provide this information, the User's Guide does not give any detailed 
information and I already looked up the GateCrystalHit.hh, where the 
comments do not more than repeat the variable names.
Can anyone clarify what means trackID, parentID, photonID, primaryID, 
eventID, and runID? Can anything of these data be used to follow the 
ways of one gamma quantum coming out of my gamma beam source?
I tried to get the meaning of each of these histograms by looking how 
many bins I have for a Hits list with about 1,000,000 entries:
TrackID is something between 1-7, parentID between 1-5.
PhotonID is always 1; I guess it just distinguishes between the two 
annihilation photons, which I don't have, because I defined a simple 
gamma beam source.
PrimaryID is also always 1.
EventID has 300*10^3 bins, maybe this is what I am looking for?
runID is always 1.

Has anyone of you experience with analyzing a hits output and can give 
me some advice? Thanks.

regards,

Astrid