[Gate-users] Gate-users Digest, Vol 41, Issue 38

[Marcin Balcerzyk]

Dear Ali.

I finished simulation of your first and second version of Xray and NoXray
files. Indeed the created zubal_PbApron_Sc_NO-XRays-140kev_2e7.bin and
zubal_PbApron_Sc_NO-XRays-140kev_2e7.binU files look the same in PMOD as
zubal_PbApron_Sc_XRays-140kev_2e7.bin and
zubal_PbApron_Sc_XRays-140kev_2e7.binU files, when you look at maxima, and
uncertainty values. 

The reason is somehow ineffective/bad Xray cutting, which you can see from
both attached files is at 34keV (see line 266 of both files) for your
material PbLight prepared from Pb that is somewhere between L1 and K line of
Pb, which makes the simulated X rays the same in both cases, as only K Xrays
are there. 

How come the cutting does not work well I do not know. Initially, both
YourPhysics.mac files look sensible, as cuts are defined (or omitted
altogether).

I just started the second set of macros you have sent me, but the X ray cut
I mentioned in the above paragraph seems the same. 

With X-ray Physics:
#       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 mm

#	I N A C T I V E    X - R A Y S
/gate/physics/setXRayCut 5 keV
/gate/physics/setDeltaRayCut 5 keV

Or just cut omission: 
#       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 mm

#	I N A C T I V E    X - R A Y S
#/gate/physics/setXRayCut 0.010 MeV
#/gate/physics/setDeltaRayCut 0.010 MeV

Without X-ray Physics:
#       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 mm

#	I N A C T I V E    X - R A Y S
/gate/physics/setXRayCut 1 GeV
/gate/physics/setDeltaRayCut 1 GeV

Then I removed any limit on electron cut in both files:
#/gate/physics/setElectronCut 2 mm
The limit is the same.

I tried to put /gate/physics/gamma/selectPhotoelectric lowenergy, and
/gate/physics/setElectronCut 0.002 mm but the range limit and energy stay
the same.

By the way, the pixel size of your Interfile is 4x4x4 mm or 4x4x16mm? Gate
reads interfiles as the first, PMOD as second. Probably Gate is right.

Maybe some of Gate developers may answer this letter (like Sebastien JAN,
who wrote YourPhysics.mac).

Marcin Balcerzyk

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