[Gate-users] "Forbid" command: cold source simulation inside a background hot source

Tue May 15 19:05:40 CEST 2018

Hi Sara

If I understand, you need to eliminate the background in this central
region, in this case can be better to use a Filter on Volume:
http://wiki.opengatecollaboration.org/index.php/Users_Guide:Tools_to_Interact_with_the_Simulation_:_Actors#Filter_on_volume

With this filter you can eliminate any particle that go inside, therefore
you will eliminate the background totally.

*But it is important to be careful about the use of filters because they
generate artificial results, they exist mainly to reduce the simulation
time if you have volumes that are not important for your experiment. Also
you can lost back-scatter from this volume to your source.*

In general all the volumes inside of a source will have scatter
interactions, but everything depends of what is your goal with the
simulation.

Best regards
Maikol

2018-05-15 16:25 GMT+02:00 Sara Zein <saz2007 at med.cornell.edu>:

> Hi Martin,
>
>
>
> We want our cold source to be located inside a cylinder that has activity.
> When using the “forbid’ command we are trying to get a completely cold
> source without any activity. However, we are not able to eliminate the
> background activity from the container cylinder. We tried to apply the
> solutions suggested by the Gate users but till now we are not successful.
> We appreciate all the suggestions.
>
>
>
> Thank you
>
>
>
> Sara
>
>
>
> *From:* Martín Belzunce <martin.sure at gmail.com>
> *Sent:* Monday, May 14, 2018 3:32 PM
> *To:* Nicolas Karakatsanis <nicolas.karakatsanis at gmail.com>
> *Cc:* gate-users <gate-users at lists.opengatecollaboration.org>; Sara Zein <
> saz2007 at med.cornell.edu>
> *Subject:* [EXTERNAL] Re: [Gate-users] "Forbid" command: cold source
> simulation inside a background hot source
>
>
>
> Hi Nikolaos, Sara,
>
> The forbid command should be used with the source TubeSource1. It's not
> necessary to define a new source for the cold region. In my experience,
> something like this should work:
>
>
>
> /gate/world/daughters/insert cylinder
> /gate/innerCylinder1/placement/setTranslation 0.0 0.0 0.0 cm
> /gate/innerCylinder1/geometry/setRmax 1.5 cm
> /gate/innerCylinder1/geometry/setHeight 6.0 cm
> /gate/innerCylinder1/setMaterial Water
> /gate/innerCylinder1/vis/forceWireframe
> /gate/innerCylinder1/vis/setColor blue
>
>
>
> /gate/source/addSource TubeSource1
> /gate/source/TubeSource1/gps/type Volume
> /gate/source/TubeSource1/gps/shape Cylinder
> /gate/source/TubeSource1/gps/radius 3.0 cm
> /gate/source/TubeSource1/gps/halfz 3.0 cm
> /gate/source/TubeSource1/setActivity 2000000 becquerel   #### to be
> specified
> /gate/source/TubeSource1/gps/particle e+
> /gate/source/TubeSource1/setForcedUnstableFlag true
> /gate/source/TubeSource1/gps/energytype Fluor18
> /gate/source/TubeSource1/setForcedHalfLife 6586.2 s
> /gate/source/TubeSource1/gps/angtype iso
> /gate/source/TubeSource1/gps/centre 0. 0. 0 cm
>
> /gate/source/TubeSource1/gps/Forbid innerCylinder1
>
>
>
> Kind regards,
>
> Martin
>
>
>
> On Wed, May 9, 2018 at 7:02 PM, Nicolas Karakatsanis <
> nicolas.karakatsanis at gmail.com> wrote:
>
> Dear
>
> GATE users
>
> ,
>
> On behalf of my colleague, Dr. Sara Zein, I am forwarding you her
> question below.
>
> We
>
>  would appreciate any help from the GATE community.  
>
>
>
> We would like
>
>  to simulate a cylindrical radioactive source having a hollow center
> without activity.
>
> We are
>
>  using the cold source command "Forbid" on the region
>
> we wish
>
>  to exclude from
>
> our
>
>  source. However the background activity from the larger source still
> persists.
>
> 
>
> Below you
>
> may
>
> find
>
> our
>
> code.
>
> /gate/source/addSource TubeSource1
> /gate/source/TubeSource1/gps/type Volume
> /gate/source/TubeSource1/gps/shape Cylinder
> /gate/source/TubeSource1/gps/radius 3.0 cm
> /gate/source/TubeSource1/gps/halfz 3.0 cm
> /gate/source/TubeSource1/setActivity 2000000 becquerel   #### to be
> specified
> /gate/source/TubeSource1/gps/particle e+
> /gate/source/TubeSource1/setForcedUnstableFlag true
> /gate/source/TubeSource1/gps/energytype Fluor18
> /gate/source/TubeSource1/setForcedHalfLife 6586.2 s
> /gate/source/TubeSource1/gps/angtype iso
> /gate/source/TubeSource1/gps/centre 0. 0. 0 cm
>
> /gate/world/daughters/name innerCylinder1
> /gate/world/daughters/insert cylinder
> /gate/innerCylinder1/placement/setTranslation 0.0 0.0 0.0 cm
> /gate/innerCylinder1/geometry/setRmax 1.5 cm
> /gate/innerCylinder1/geometry/setHeight 6.0 cm
> /gate/innerCylinder1/setMaterial Water
> /gate/innerCylinder1/vis/forceWireframe
> /gate/innerCylinder1/vis/setColor blue
>
> /gate/source/addSource TubeSource2
> /gate/source/TubeSource2/gps/type Volume
> /gate/source/TubeSource2/gps/shape Cylinder
> /gate/source/TubeSource2/gps/radius 1.5 cm
> /gate/source/TubeSource2/gps/halfz 3 cm
> /gate/source/TubeSource2/setActivity 2000000 becquerel   #### to be
> specified
> /gate/source/TubeSource2/gps/particle gamma
> /gate/source/TubeSource2/gps/monoenergy 511. keV
> /gate/source/TubeSource2/gps/angtype iso
> /gate/source/TubeSource2/gps/centre 0. 0. 0 cm
> /gate/source/TubeSource2/gps/Forbid innerCylinder1
> /gate/source/TubeSource2/dump 1
> /gate/source/list
>
>
> Thank you
>
>  in advance
>
> ,
> Regards
>
> Sara Zein
>
>
>
>
>
> *Nikolaos (Nicolas) A.* *Karakatsanis, PhD, DABSNM*
> Assistant Professor of Biomedical Engineering in Radiology
> Weill Cornell Medical College
>
> *Weill Cornell Medicine*
> Division of Radiopharmaceutical Sciences, Department of Radiology
> 515 East 71st Street, S-120, New York, NY 10021
> nak2032 at med.cornell.edu
>
>
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