[gate-users] Re: gate-users Digest, Vol 12, Issue 19

[D.J. van der Laan]

Do you use things like 'energy resolution' and 'spatial blurring' in 
your digitizer chain? Since these modules also use random numbers, this 
will result in different random numbers when de sensitive detectors are 
attached to different volumes. If this is the case, you could try to 
leave these modules out and model them afterwards 'by hand'.

However, can't you use the 'scanner' system? I don't think this this 
system imposes any constraints on your geometry. You don't have 
coincidence sorting, so you have do this afterwards yourself, but you 
don't have coincidence sorting now.

Regards,

Jan

janecekm at mir.wustl.edu wrote:
> Hello GATE?ers,
> 
>  
> 
> I?m looking for some help with locking the random seed. We are simulating a 
> system with two different kinds of detectors (one hi-res and one medium 
> resolution), and we therefore have to simulate each simulation setup twice: one 
> time with detector A attached and the sensitive detector (SD), and the second 
> time with detector B attached and the SD (since the attachment tree is of single 
> branch). During these simulations, the non-attached system is attached as 
> PhantomSD. These two simulations are then together sorted to get the 
> coincidences. To be able to do this however we need to lock the random seed. We 
> have tried to lock it with the following line:
> 
>  
> 
> /random/resetEngineFrom my_rndm_file.rndm
> 
>  
> 
> Even though the results are identical each time we run a simulation with 
> detector A (or B), we get a different simulation when switching to detector B 
> (or A). (The number of events simulated are different in the two runs, and the 
> coincidences are randoms.) Any help on this matter, how to lock the random seed, 
> is appreciated. Or is it that changing the attachment and SD, changes the 
> simulation? How do we in that case simulate our system?
> 
>  
> 
> Martin Janecek
> 
> 
> ************************************************
> Martin Janecek, Ph.D.
> Washington U. School of Medicine
> Dept. of Radiological Sciences
> Campus Box 8225
> 510 South Kingshighway
> St. Louis, MO 63110
> 
> 
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-- 
D.J. van der Laan
Delft University of Technology
Mekelweg 15, room 2.00.020
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The Netherlands

E: d.j.vanderlaan at tnw.tudelft.nl
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