[Gate-users] Physics cut off in GATE

[AliAsghar Parach]

Dear gaters

I have  questions about X-Rays production in GATE.
1-when I change XRay and delta rays cut from 1 keV to 1GeV there was
seen no change in dose out put and the gaterun.dat file in 2 cases are
exactly the same. But when I change the electron cut (even if slightly
changed) the results are different and the gaterun.dat files of them
are different too.
I would like to know what is it's reason?

2- when the cut off of the X-Rays is 10 keV the physics properties in
the gate running page is as below:
========= Table of registered couples ==============================

Index : 0     used in the geometry : Yes     recalculation needed : No
 Material : Vacuum
 Range cuts        :  gamma 0.000e+00 fm     e- 1.000e+02 nm     e+
1.000e+00 mm
 Energy thresholds :  gamma 9.900e+02 eV     e- 9.900e+02 eV     e+
9.900e+02 eV
 Region(s) which use this couple :
    DefaultRegionForTheWorld

Index : 1     used in the geometry : Yes     recalculation needed : No
 Material : Water
 Range cuts        :  gamma 0.000e+00 fm     e- 1.000e+02 nm     e+
1.000e+00 mm
 Energy thresholds :  gamma 9.900e+02 eV     e- 9.900e+02 eV     e+
3.387e+02 keV
 Region(s) which use this couple :
    DefaultRegionForTheWorld

Index : 2     used in the geometry : Yes     recalculation needed : No
 Material : Lead
 Range cuts        :  gamma 0.000e+00 fm     e- 1.000e+02 nm     e+
1.000e+00 mm
 Energy thresholds :  gamma 9.900e+02 eV     e- 9.900e+02 eV     e+
1.280e+00 MeV
 Region(s) which use this couple :
    DefaultRegionForTheWorld

what means these information?
we defined X-ray cut to 10keV but in this output the gamma Energy
thresholds is about 1keV?

when this cutoff changed to 1GeV the results are the same, ie: gamma
Energy thresholds is about 1keV yet.
what is this effect reason?
(the threshold of electron production seems to be true)

kind regards.


-- 
Ali Asghar Parach,Ph.D. student in Medical Physics,Tarbiat Modares
University,Tehran,Iran