[Gate-users] Noise parameters

[Ashley Devarim]

Hi David,

Thank you very much for your answer, would you mind please if you take a look at my questions below :


> Hello,
> actually, I don't understand what you want to set up... The setLambda parameter (7.57 mus in your exemple) is equal to the mean time between to consecutives noise events in a Poisson distributed noise source. The inverse of this value is the noise frequency, thus.



1) but the difference time distribution is an exponential and the setLambda parameter is the power of the distribution, even in this case the setLambda parameter would be simply the inverse of the noise frequency ?

2) For example if I have a noise values varying between 0 and 90 keV  and mean value = 60 keV , what would be the setMean and setSigma parameters in this case ?  


> Concerning, the eventID number, it is due to the fact that noise events are not produced by physical interaction of particles with detectors (which can be attached to a particle emission event number, which is eventID). The noise events are described as independent source of detector signal, not correlated to any physical particle emission, and are then marked with the special event number (-2).



3) here the reason for my question was,  that the noise events participate to the coincidences events like a particle emission events and I was wondering if this is happening in real life ? I thought that noise should be mixed with the signal and not seen as separated event ( like energy blurring )?  what do you think please ?



Kind Regards

Ashley




> 
> N.B : A message of Soeren Dittrich had written, mentioned that infinite loop where observed using this module. I used it without problem 2 year ago, but may be new developpements invalidate it. I can't use GATE in my home for the time being, and thus, I was not able to check the problem. As soon as I get back a usable version of linux with ROOT/GATE working, I'll take a look on this problem (and on the setDepth problem you mentioned and that I were never able to investigate).
> 
> cheers.
> 
> D. Guez
> 
> Ashley Devarim a écrit :
> 
> 
> Dear Gate users,
> 
> I need help please, how can I set up the parameters of noise using the following commands to reproduce a real case, especially noise time distribution parameters  :
> 
> 
> /gate/distributions/name energy_distrib
> 
> /gate/distributions/insert Gaussian
> 
> /gate/distributions/energy_distrib/setMean 450 keV
> 
> /gate/distributions/energy_distrib/setSigma 1 keV
> 
> /gate/distributions/name dt_distrib
> 
> /gate/distributions/insert Exponential
> 
> /gate/distributions/dt_distrib/setLambda 7.57 mus
> 
> /gate/digitizer/Singles/insert noise
> 
> /gate/digitizer/Singles/noise/setDeltaTDistribution dt_distrib
> 
> /gate/digitizer/Singles/noise/setEnergyDistribution energy_distrib
> 
> 
> Also, I don't understand : The special event ID, event_ID= -2 , is attributed for those noise events. why GATE consider noise events as a separated events !!!  is that what happens in real life ?
> 
> 
> Looking forward to your answer
> and Thank you very much for your help
> 
> Ashley
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