[gate-users] Time Resolution and More

Mikhail Shilov mshilov1 at jhmi.edu
Thu May 19 17:10:17 CEST 2005

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:


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 ? 
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?

Mikhail A. Shilov
The Johns Hopkins University
Department of Radiology
Division of Medical Imaging Physics
Tel:  443-287-7315

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