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

[Esteban Venialgo]

Dear Yannick,

I've utilized user-defined histograms for energy distributions but 
unfortunately I have not simulated user-defined angle distributions. For 
energy, I defined the histogram in this way:

# Energy distribution of the source
/gate/source/cesioXrays/gps/energytype Arb

# Define the name of histogram, max and min values
/gate/source/cesioXrays/gps/histname arb                     
/gate/source/cesioXrays/gps/emin 0.003954 MeV
/gate/source/cesioXrays/gps/emax 0.038 MeV

# The histogram's bins
/gate/source/cesioXrays/gps/histpoint 0.003954 0.0143        
/gate/source/cesioXrays/gps/histpoint 0.004331 0.0064       
/gate/source/cesioXrays/gps/histpoint 0.004451 0.040       
..
..
..
/gate/source/cesioXrays/gps/histpoint 0.037255 0.215       
/gate/source/cesioXrays/gps/histpoint 0.037349 0.0481       

# Tipe of interpolation
/gate/source/cesioXrays/gps/arbint Lin

 
It worked for me in GATE.

There is a GPS example web-page, and I've found an example that does 
more or less what you need in your simulation:
http://reat.space.qinetiq.com/gps/examples/ex23.htm


>From my little experience, I would recommend that the source should be 
simulated independently from the complete setup. For example, you could 
simulate your source placed in the center of a hollow sphere detector, 
check the singles that were generated in the detector by source and 
verify that angle distribution is correct. Then, use that validated 
source in the complete simulation.

  Best regards, Esteban.









Grondin Yannick wrote:
> 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
>>
>>
>>
>>
>> _______________________________________________
>> Gate-users mailing list
>> Gate-users at lists.opengatecollaboration.org
>> http://lists.opengatecollaboration.org/mailman/listinfo/gate-users
>>
>>
>>     
>
>