[Gate-users] back-to-back gamma source

[Fernando Rannou]

Try

/gate/physics/gamma/selectCompton disable


In ROOT you can use

if (eventID1 == eventID2)  ===> true
else not true

However, if scatter is on then a true coincidence
can still be scatter. So true does not say it is a straight
line (necessarily)

Fernando





Eunsin Lee wrote:
> Hi Fernando,
>
> This is what I was going to ask about?
> How do we tell scatter and true coincidences in Gate output?
> You said "turn it off" and how do I do that?
> Sorry I'm a newer to this..
>
> Thanks a lot,
> Eunsin
>
>
>
>
>
> On Aug 2, 2010, at 5:22 PM, Fernando Rannou wrote:
>
>   
>> Scatter?
>>
>> Turn it off to be sure
>>
>> Eunsin Lee wrote:
>>     
>>> Dear Users,
>>>
>>> I simulated a cylindrical PET system using point source (back-to-back gamma) at the center of the detector for a simple study..(with cylindrical phantom filled with just air).
>>> If my understanding is correct, coincidence events should have back-to-back gamma's, which tell us LOR in r-z plane should be simply a line passing through the center (0,0). In other words Z1+Z2 should be very close to zero. Below shows actual z position detected for two gammas in each coincidence events in my simulation output. Looks like something else is going on...
>>> Can anybody tell me what's missing?
>>>
>>> 	    Z1                    Z2
>>> 	-71.3593	46.7426
>>> 	-71.5756	-50.5808
>>> 	-71.5233	69.8813
>>> 	-71.004		35.5772
>>> 	-71.9038	15.7994
>>> 	-73.7647	-4.99394
>>> 	-71.5314	-11.8862
>>> 	-70.284		-12.6473
>>> 	-73.0036	63.4071	0	
>>> 	-71.3191	61.7319	0	
>>> 	-71.9782	-12.7522
>>> 	-72.9756	-68.4205
>>> 	-73.9974	39.802
>>> 	-73.1717	2.25218
>>> 	-71.4347	-44.9677
>>> 	-71.7795	-73.2273
>>> 	-70.6986	-19.3314
>>> 	-73.6817	-7.85506
>>> 	-73.5097	-1.3274
>>> 	-70.4753	54.6905
>>>
>>> Thanks,
>>> Eunsin
>>> _______________________________________________
>>> Gate-users mailing list
>>> Gate-users at lists.opengatecollaboration.org
>>> http://lists.opengatecollaboration.org/mailman/listinfo/gate-users
>>>
>>>  
>>>       
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>
>
>   

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en busca de virus y otros contenidos peligrosos,
y se considera que está limpio.
MailScanner agradece a transtec Computers por su apoyo.