[Gate-users] Re: using source "confine" option

[Marcin Balcerzyk]

Hi Bosky.

There is an user extension Forbid to Gate which may be of help to you, see
the list, at
http://lists.healthgrid.org/archives/gate-users/2008-March/002560.html

Best regards

Marcin Balcerzyk
Univesrsidad Complutense de Madrid


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Message: 1
Date: Thu, 8 May 2008 10:01:44 -0400
From: "Ravindranath, Bosky" <bosky at bnl.gov>
Subject: [Gate-users] using source "confine" option
To: <gate-users at lists.healthgrid.org>
Message-ID:
	<85F229EA6E8EE64FA3A83857408CC9928953BF at exchangemb2.bnl.gov>
Content-Type: text/plain;	charset="iso-8859-1"

To Giovanni Santin and Gate users,
 
I have  a couple of questions about the "confine" option when defining a
source in GATE.  I am trying to define a warm background with a hot spot in
the center and I want to keep these two sources independent of one another,
i.e have no overlap in the source emission points. 
I tried using the "confine" command in the following way:
 
#Phantom 1: Warm background phantom
/gate/world/daughters/name phantom
/gate/world/daughters/insert cylinder
/gate/phantom/setMaterial Water
/gate/phantom/vis/forceWireframe
/gate/phantom/vis/setColor white
/gate/phantom/geometry/setRmax   72.65923 mm 
/gate/phantom/geometry/setRmin   0. mm  
/gate/phantom/geometry/setHeight 96.46 mm #array only. increase for OFOV
/gate/phantom/attachPhantomSD

#Phantom 2: Hot Spot Phantom
/gate/phantom/daughters/name phantom_sp1 /gate/phantom/daughters/insert
sphere /gate/phantom_sp1/setMaterial Water
/gate/phantom_sp1/vis/forceWireframe
/gate/phantom_sp1/vis/setColor blue
/gate/phantom_sp1/geometry/setRmax   7.5 mm  
/gate/phantom_sp1/geometry/setRmin   0. mm  
/gate/phantom_sp1/placement/setTranslation 0. 0. 0. mm  
 
Followed by my Source definition:
# background Source
/gate/source/addSource background
/gate/source/background/setActivity  3851374  becquerel
/gate/source/background/setType backtoback
/gate/source/background/gps/particle gamma
/gate/source/background/gps/energytype Mono
/gate/source/background/gps/monoenergy 0.511 MeV
/gate/source/background/setForcedUnstableFlag true
/gate/source/background/setForcedHalfLife 6586 s
/gate/source/background/gps/type Volume /gate/source/background/gps/shape
Cylinder /gate/source/background/gps/radius 72.65923 mm
/gate/source/background/gps/halfz 48.23 mm
/gate/source/background/gps/centre 0. 0. 0. cm
/gate/source/background/gps/confine phantom
/gate/source/background/gps/angtype iso
 
# hotspot Source
/gate/source/addSource twogamma
/gate/source/twogamma/setActivity 35958.45 becquerel
/gate/source/twogamma/setType backtoback /gate/source/twogamma/gps/particle
gamma /gate/source/twogamma/gps/energytype Mono
/gate/source/twogamma/gps/monoenergy 0.511 MeV
/gate/source/twogamma/setForcedUnstableFlag true
/gate/source/twogamma/setForcedHalfLife 6586 s
/gate/source/twogamma/gps/type Volume /gate/source/twogamma/gps/shape Sphere
/gate/source/twogamma/gps/radius 20 mm /gate/source/twogamma/gps/centre 0.
0. 0. mm /gate/source/twogamma/gps/confine phantom_sp1
/gate/source/twogamma/gps/angtype iso
 
The hot spot source gets confined to its confinement volume(phantom_sp1),
however the background source is uniformly distributed over the regions of
"phantom" as well as "phantom_sp1". I expected that the background source
will be confined to the area of (phantom-phantom_sp1)..which in this case
should be a cylinder with a hole in the center. I also tried defining the
two phantoms as the daughters of the world, but that did not confine the
background activity either.
 
 
Any suggestions appreciated.
 
Thanks.
Bosky


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