[Gate-users] Ion source - timestamp problem GATE 6.1

[Gergely Patay]

Dear Enrique,

the ion timestamp problem is caused by a protected (i.e. non user-settable) 
"isGeneralIon" field in the Geant4 G4ParticleDefinition class (for the details, 
see 
http://lists.opengatecollaboration.org/mailman/private/gate-users/2015-April/008344.html 
) .

A minimal workaround might be as follows :

1) change visibility of isGeneralIon from protected to public:
geant4/particles/management/include/G4ParticleDefinition.hh:402
-   protected:
+   public:
        G4bool isGeneralIon;

(this might be modified *without* recompiling Geant4)

2) add the following line to gate/source/physics/src/GateVSource.cc:269
           GetParticleDefinition()->SetPDGLifeTime(0);
+         GetParticleDefinition()->isGeneralIon=false;

3) recompile Gate with the modified header file.

Since it requires to modify a file *outside* of the Gate source tree, I'm not 
sure how to do it automatically.

best regards,
  Gergely

--
Gergely Patay
Mediso Ltd.


On 2016-01-12 18:09, Enrique Muñoz Albaladejo wrote:
> Thank you very much for your response, the problem seems to be exactly as you
> describe it. It looks like it ignores any time settings I define and takes the
> time of the simulation to be that which makes the source run out of activity.
>
> I have encountered this problem when simulating a Na22 source with GATE 7.1 and
> geant4.10.01.p02, and a colleague of mine has the same problem with GATE 6.1 and
> Geant4 9.4 (she wanted to simulate 176 Lutetium).
>
> I tried to read through the Geant4 code and I can't figure out why the function
> SetPDGLifeTime() would ignore the attempt to modify the lifetime of an ion, but
> my programming knowledge isn't that deep.
>
> Thanks again.
>
> Enrique Muñoz
>
> On 04/01/16 09:37, STRYDHORST Jared wrote:
>> What version of GATE and Geant4 are you using and what ion?
>> GATE schedules the decay of ions itself according to the activity set by the
>> user. To do so, it calls a function that sets the lifetime of the ion in
>> Geant4 to zero so it decays immediately when it's created. However, in version
>> 10 (.1?, .2? I don't know exactly when the change was made.) of Geant4, the
>> function (SetPDGLifeTime()) now ignores any attempts to modify the lifetime of
>> an ion. So the ion is created by GATE, but then Geant4 calculates the decay
>> time according to the real half-life of the ion.
>>
>> Jared STRYDHORST
>>
>> Laboratoire Imagerie Moléculaire In Vivo (IMIV)
>> UMR 1023 Inserm/CEA/Université Paris Sud - ERL 9218 CNRS
>> CEA/I2BM/Service Hospitalier Frédéric Joliot
>> 4, place du Général Leclerc
>> 91401 ORSAY Cedex
>>
>> <mailto:karima.ait-aissa at cea.fr>
>> <http://i2bm.cea.fr/dsv/i2bm/shfj/imiv>http://i2bm.cea.fr/dsv/i2bm/shfj/imiv
>> --------------------------------------------------------------------------------
>> *De :* gate-users-bounces at lists.opengatecollaboration.org
>> [gate-users-bounces at lists.opengatecollaboration.org] de la part de Enrique
>> Muñoz Albaladejo [Enrique.Munoz at ific.uv.es]
>> *Envoyé :* lundi 21 décembre 2015 12:32
>> *À :* gate-users at lists.opengatecollaboration.org
>> *Objet :* [Gate-users] Ion source - timestamp problem GATE 6.1
>>
>> Dear all,
>>
>>
>> I am trying to use an ion source for a PETscanner.
>>
>> The simulation provides strange values for the time stamp of the singles.
>> The parameter  "setTimeStop"  was set to 50s, but the timestamp of the first
>> detected single was 3.4x10^17 s.
>>
>> I would like to know if there is any solution to this problem.
>>
>> Best regards,
>>
>> Enrique
>
>
>
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