[Gate-users] Re : Preprocessing Hits file or adding layerIDs

[Samuel BURG]

Hi,

I don't know if you already get an answer, it seems not.

For your electron question :
1) I think you are simulating F-18 ? or some other b+ emitter.
2) I you don't care on the electron track, you should simulate back-to-back 
emission.
3) electron cut is for secondary particles, not for primary ones.

For your 50x1mm layer question, I don't clearly understand what you want to do 
....

If you have soem "brutal force" computer/cluster you can still simulate all the 
stuff and then make a root software to post-process the data.

regards,

-----------------------------------------------------------
Samuel Burg


Mail : <samuel_burg at yahoo.fr>
-----------------------------------------------------------
"Aw, come on, who would be so stupid as to insert a cast
to make an error go away without actually fixing the error?"
Apparently everyone. 
-- Raymond Chen --
-----------------------------------------------------------




________________________________
De : David Oxley <d.c.oxley at rug.nl>
À : gate-users at lists.opengatecollaboration.org
Envoyé le : Lun 14 mars 2011, 11h 49min 53s
Objet : [Gate-users] Preprocessing Hits file or adding layerIDs


Dear Gate-Users, 

I am not greatly experienced with GATE and am struggling to get it to do quite 
what I want, perhaps someone can help. 

I am using GATE v6.0.0 on Ubuntu 10.04 and am simulating a full-ring, 
cylindrical PET scanner. 

I do not have a fixed scanner design, so am working with a generic, continuous 
cylindrical volume and will digitize/voxelise the data offline.

My problem is that I want to keep track of all Compton and Photoelectric events, 
but, if possible, want to avoid processing the Hits file as I am not interested 
in the 10-20 collisions of the electron. For each of the ~15 lines it generates 
I am only interested in 2.  In a sense, I want the photon hits only. 

I have tried changing my electron cut value to very large values, but still see 
electrons in the Hits file.

From what I can gather even the SinglesAdder file will still add a Compton and a 
photoelectric effect if they are in the same volume. I want to avoid this, and 
see the following options. 

1)
Define volumes as small as the finest resolution I am interested in (~order of 
mm-s). Of course this is inefficient, but more problematic is that I run out of 
layerIDs to play with. It seems there are only 5. But if I make a continuous 
ring (which I do want to make) I would need at least 50 different layers of 1mm 
each. 


2)
Apply some sort of cut to the hits file, to sum the electron deposits into the 
Compton deposits (as these are zero). 


Has anyone else had similair difficulties? Is it possible (advisable?) to add 
layerIDs to the source code, if so could someone point me in the right 
direction? 

Is there a way to filter the Hits file, without summing inside volumes? 

I appreciate that it is perhaps unorthodox to want to keep two interactions, 
even if there were only in one crystal, but I hope it is still possible. 


I hope my message is clear, but please get back to me if there are questions. 
Thanks in advance for any help. 


Kind regards,

Dave Oxley 

================================= 

Dr. David Oxley

Postdoctoral Researcher 
Kernfysisch Versneller Instituut
Zernikelaan 25
NL-9747 AA Groningen
The Netherlands

d.c.oxley at kvi.nl
d.c.oxley at rug.nl
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