[Gate-users] Moving Point source

[Tianyu Ma]

Hello ayanas:

	I guess GATE deals with a "moving" source which is
confined to a moving phantom in such way: First, sample
a source particle. Second, check if the location of the 
source particle is inside the moving phantom. If not, go
back to the first step until a particle inside the phantom
is sampled. So if your moving phantom is too large comparing
to the size of the source, the sampling effciency will be
very low and may produce such error messages. You man solve
this problem by reducing the size of the phantom. However, it
seems to be unavoidable that using source confinment in GATE 
will always cause the decrease of computing efficiency... Is 
that so?

======================================
Tianyu Ma, Ph.D.
Department of Engineering Physics,
Tsinghua University, China
Tel: 86-10-62796201
Fax: 86-10-62782658
Email: maty at tsinghua.edu.cn
======================================

-----------original message-------------------
>
>Hello,
>I am trying to set-up a "moving Point source". 
>I thought I could simply do it by defining a very small sphere 
>embedded in a another sphere phantom and defining GPS as a sphere as in 
>the macro below.
>
>However, when I decrease the radius of the "movsource" below 1 cm, 
>say, to 0.0001 mm to make the sphere source point like
>I get error messages " LoopCount = 100000
>Either the source distribution >> confinement
>or any confining volume may not overlap with
>the source distribution or any confining volumes .."
>
>Could anyone comment on what I am doing wrong in the macro below? Or any 
>other suggestions or simpler methods for a moving Point source? 
>
>thank you very much,
>
>ahmet.
>
>
>---------------------8<----------------
># PHANTOM
>#
>/gate/world/daughters/name Phantom
>/gate/world/daughters/insert sphere
>/gate/Phantom/geometry/setRmin 0.  cm
>/gate/Phantom/geometry/setRmax 25.  cm
>/gate/Phantom/placement/setTranslation 0 25 0 cm
>/gate/Phantom/setMaterial Air
>/gate/Phantom/vis/setColor green
>#/gate/Phantom/vis/forceWireframe
>/gate/Phantom/attachPhantomSD
>/gate/Phantom/moves/insert translation
>/gate/Phantom/translation/setSpeed 0 0.004 0 cm/s
>/gate/Phantom/vis/setVisible 0
>
># A d d   a n  e x t r a   o b j e c t   f o r   s o u r c e   c o n f i n e m e n t
>/gate/Phantom/daughters/name movsource
>/gate/Phantom/daughters/insert sphere
>/gate/movsource/geometry/setRmin 0 cm
>/gate/movsource/geometry/setRmax 1 cm
>/gate/movsource/placement/setTranslation 0. 0. 0 cm
>/gate/movsource/setMaterial Air
>/gate/movsource/vis/setColor magenta
>#/gate/movsource/vis/forceWireframe
>/gate/movsource/attachPhantomSD
>
>### M o v i n g   S o u r c e   C o n f i n e m e n t 
>/gate/source/addSource SourceConfinement
>/gate/source/SourceConfinement/gps/type Volume
>/gate/source/SourceConfinement/gps/shape Sphere
>/gate/source/SourceConfinement/gps/radius 25 cm
>/gate/source/SourceConfinement/gps/centre 0 25 0 cm
>/gate/source/SourceConfinement/gps/particle gamma
>/gate/source/SourceConfinement/setActivity 10 Bq
>/gate/source/SourceConfinement/gps/energy 122. keV
>/gate/source/SourceConfinement/gps/confine movsource_P
>/gate/source/SourceConfinement/gps/angtype iso
>/gate/source/SourceConfinement/gps/mintheta 0 deg
>/gate/source/SourceConfinement/gps/maxtheta 180 deg
>/gate/source/SourceConfinement/gps/minphi 0 deg
>/gate/source/SourceConfinement/gps/maxphi 180 deg
>-----------------8<----------------------------------
>
>-- 
>Ahmet Sedat Ayan, Ph.D
>
>Department of Radiology
>University of Pennsylvania
>Philadelphia, PA 19104
>
>Voice      : (++ 1 215) 349-5751 (W) (GMT-5)
>
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