[Gate-users] Ion source - timestamp problem Gate 6.0.1

[Mercedes Rodriguez]

Hello Uwe and Didier,

Thank you very much for looking at the problem with the ion source. I 
also tried running my simulation using Gate 6.1 but several problems 
appeared (apart from the one related to the timestamp) that I gave up 
and returned straightaway to Gate 6.0. I'm interested in using an ion 
source but I don't know how to solve the problem. It'd be very very 
useful if the Gate developers can have a quick look at it.

With my best regards,
Mercedes

On 3/30/2011 3:56 AM, Uwe Pietrzyk wrote:
>
> Hi Didier,
>
> I tried this issue with GATE 6.1 and found the same problem as Mercedes in
> her runs. Using ion sources (ex: O-15) give simply crazy time stamps, 
> starting with:
>
> 1.01108082430250235006497e+02  !!
>
> according to the ascii printout of "singles".
>
> Using a simple positron source with O-15 decay times I receive:
>
> 9.08127148493307485720334e-07 !!,
>
> which to me look quite different. Something is wrong there.
> As I mentioned some time ago, also the scatter fractions look
> differently.
>
> Kind regards,
>
> Uwe
> -----
> On 30.03.2011, at 04:48, Didier Benoit wrote:
>
>> Hi Mercedes,
>>
>> Could you test your macro with GATE 6.1? Many bugs have been fixed 
>> concerning the sources in GATE.
>>
>> Kind Regards,
>> Didier Benoit
>>
>> On Mar 22, 2011, at 7:16 PM, Mercedes Rodriguez wrote:
>>
>>> Dear Gate Users,
>>>
>>> I'm trying to use an ion source (18F, 22Na or 15O) for a PETscanner 
>>> geometry and the simulation provides strange results for the 
>>> timestamps. For instance, I run the simulation using 18F, 
>>> setTimeSlice=60 s and the time histogram for coincidence events goes 
>>> from 0 to ~100000 s, following an exponential decay. No randoms and 
>>> no scattered events are produced. My guess is that time sampling is 
>>> incorrect when using an ion source.
>>>
>>> When I run the simulation for e+ that have an 18F energy spectrum 
>>> (and the corresponding half life) I obtain randoms and scattered 
>>> events different from zero and the time histogram is what I expect, 
>>> flat from 0 to 60 s. I'm attaching a pdf file with a couple of 
>>> graphs for 18F (ion source and e+), Ao=4e5 Bq, TimeSlice=60s.
>>>
>>> Any idea of what could be happening?
>>>
>>> Regards.
>>> Mercedes
>>>
>>> -- 
>>> Mercedes Rodriguez Villafuerte, Ph.D.
>>> Visiting Professor, Cherry's Lab
>>> BME, UC Davis
>>> 451 Health Sciences Drive, GBSF 2505
>>> Davis, CA 95616
>>>
>>> Tel: 530-752-6387
>>>
>>> <IonSource.pdf>_______________________________________________
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>>> Gate-users at lists.opengatecollaboration.org 
>>> <mailto:Gate-users at lists.opengatecollaboration.org>
>>> http://lists.opengatecollaboration.org/mailman/listinfo/gate-users
>>
>> ----------------------------------------------------------------
>> Didier BENOIT, GATE Engineer
>> Imagerie et Modélisation en Neurobiologie et Cancérologie (IMNC)
>> IMNC – UMR 8165 CNRS – Université Paris 7 – Université Paris 11
>> Campus d’Orsay
>> Bâtiment 440
>> 91406 ORSAY Cedex
>>
>> Tél : (33) 1 69 15 68 76
>> E-mail : benoit at imnc.in2p3.fr <mailto:benoit at imnc.in2p3.fr>
>> http://www.imnc.in2p3.fr
>> ----------------------------------------------------------------
>>
>>
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>
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> ----------------------------------------------------------------------/
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-- 
Mercedes Rodriguez Villafuerte, Ph.D.
Visiting Professor, Cherry's Lab
BME, UC Davis
451 Health Sciences Drive, GBSF 2505
Davis, CA 95616

Tel: 530-752-6387