[gate-users] Time Resolution and More

[Mikhail Shilov]

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 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?
Thanks

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