[gate-users] Time Resolution and More

[Martin Rey]

Mikhail Shilov wrote:

>Greetings All,
>
>I'm trying to understand some confusing results I get from running Gate
>simulation for ecat PET scanner.
>First of all I've noticed that when I do:
>
>/gate/digitizer/Singles/deadtime/setDeadTime  # ns
>
>and then do:
>
>/gate/digitizer/Singles/deadtime/describe
>
>  
>
It must be cause ps is the Gate time default unit.

>It prints out time which is 1000. times the time I specified in the
>first command. Has anyone noticed that before?
>Though, it looks like it's using the specified value in the simulation
>but I'm not sure.
>
>Also, when I look at the energy spectrum of the recorded singles it
>extends well beyond 511 keV to up to 2 keV.
>The only explanation I find is that the digitizer module integrates the
>hits in the detector over some time windows and adds up their energy. I
>couldn't find any information on the time resolution or simulation of
>the 'pile up' in the crystals in the manual. 
>Is 'timeResolution' module responsible for this ?
>
The timeResolution is certainly not responsible for this and doesn't 
exist if you hadn't insert it in your digitizer chain.

> 
>Why does it add up the hits if I didn't insert this module in the
>digitized chain and what is the default time resolution?
>Thanks
>
>Mikhail A. Shilov
>The Johns Hopkins University
>Department of Radiology
>Division of Medical Imaging Physics
>Tel:  443-287-7315
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>  
>