[gate-users] Gamma Energy Cut

[Assen Kirov]

Mikhail,

Photons under 250 keV can still affect your results since they can sum 
up to give
something in your E window.  They may also affect the dead time.
 
Try this format just before /run/initialize.
Assen


#
#    P H Y S I C S
#


#       EM  P R O C E S S
/gate/physics/gamma/selectRayleigh lowenergy
/gate/physics/gamma/selectPhotoelectric standard
/gate/physics/gamma/selectCompton standard

#    I N A C T I V E    S E C O N D A R Y   E L E C T R O N S
/gate/physics/setElectronCut 2. km

#       X - R A Y S
/gate/physics/setXRayCut 250. keV
/gate/physics/setDeltaRayCut 250. keV

Mikhail Shilov wrote:

>Greetings All,
>
>I just started using GATE 1.0.2  to run PET scanner simulations. I was
>wondering if there is a way to set an energy cut for gamma photons
>without modifying the source code. Since we use 250 keV thresholds in
>our detectors we don't really need to track gamma photons with lower
>energies. As far as I understand the energy thresholds for the gamma
>rays are listed in the cuts-material couples before the simulation. For
>example:
>
>========= Table of registered couples ==============================
>
>Index: 0     used in the geometry: Yes     recalculation needed: No 
>Material: Air
>Range cuts        :  gamma 1 mm    e- 10 m    e+ 1 mm
>Energy thresholds :  gamma 990 eV    e- 2.39817 MeV    e+ 990 eV
>Region(s) which use this couple : 
>DefaultRegionForTheWorld
>
>Also, for some reason, it always sets the range cut for electrons to
>10m independently to what I set it in: 
>gate/physics/setElectronCut
>
>Thank you.
>
>
>
>
>
>Mikhail A. Shilov
>The Johns Hopkins University
>Department of Radiology
>Division of Medical Imaging Physics
>Tel:  443-287-7315
>Fax:  410-614-1977
>mailto: mshilov1 at jhmi.edu
>_______________________________________________
>gate-users mailing list
>gate-users at lphe1pet1.epfl.ch
>http://lphe1pet1.epfl.ch/mailman/listinfo/gate-users
>
>  
>

-- 
Assen S. Kirov, Ph.D.
Assistant Attending Physicist
Department of Medical Physics, Room S-1119H
Memorial Sloan-Kettering Cancer Center
1275 York Avenue,  New York, NY 10021
tel (212) 639-7126, fax (212) 717 3010