[Gate-users] RE : emission angular distribution of a gamma source

[Grondin Yannick]

Dear Esteban,

Thank you for your answer! But I realised that my question was not precise enough. 
Indeed, I used GPS to define the source. My question is about the angular distribution of the emitted particles.
Usually I guess, people use isotropic emission with this command :

/gate/source/YOUR_SOURCE/gps/angtype iso

By searching in GATE commands list, I found that it seems to be possible to have a user-defined angular distribution, by this command:

/gate/source/YOUR_SOURCE/gps/angtype user

Since I want to define an angular distribution  of the "phi" angle of the emitted particles, I used the command:

/gate/source/YOUR_SOURCE/gps/histname phi

and then I defined an histogram with these command lines :

/gate/source/YOUR_SOURCE/gps/histpoint 1.382660 0.440000 
/gate/source/YOUR_SOURCE/gps/histpoint 1.401275 0.550000
. . .
. . .

where the first number represents the angle in rad, the second number, the weight. 
These command lines are "inspired" from the link of the GPS page you gave me, but it seems to not work in GATE: I don't get any segmentation fault, but nothing happens either ..

Moreover I have another problem :  How to say that I want isotropic distribution in theta ? 

Thank you for your help,

Regards,

Yannick





======================================
Yannick Grondin
Master Student in Medical Physics
Groupe Imagerie Médicale
Institut de Radiophysique - CHUV
Rue du Grand-Pré 1
1007 Lausanne
Switzerland
======================================
________________________________________
De : Esteban Venialgo [venialgo at cae.cnea.gov.ar]
Date d'envoi : mercredi, 13. juin 2012 18:34
À : Grondin Yannick; gate-users at lists.opengatecollaboration.org
Objet : Re: [Gate-users] emission angular distribution of a gamma source

Dear Yannick

GATE uses GPS (general particle soruce) to generate particles so you can
use the GPS commands to simulate any sources. All the commands are
equivalent except for the path of the commands.

you can find the GPS manual here:
http://reat.space.qinetiq.com/gps/new_gps_sum_files/gps_sum.htm

and in GATE, the path of the commands is the next:

/gate/source/YOUR_SOURCE/gps/

  Best regards, Esteban.



Grondin Yannick wrote:
> Hi,
>
> I'm trying to simulate a gamma source with a user-defined  emission angular distribution (histogram). It seems to be possible in GEANT4 (and the philosophy is the same as the energy distribution), but I cannot have it worked in GATE. Is that possible and how ?
>
> Thank you,
>
> Yannick
>
>
>
>
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