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Forum: Physics List
Re: Question highly un reasonable positron penetration depth in Fe. (LowEnergy, Penelope and default) (Or Chen)
Date: 29 Jul, 2008
From: michel maire <michel maire>

On Tue, 29 Jul 2008 00:51:38 GMT, Or Chen wrote:
> Hey,
> 
> I'm working on a PAS (Positron Annihilation Spectroscopy) simulation,
> 
> In the experimental system's most basic structure, positrons leave the
> source at about ~200*keV, loose about 10*keV ant the source's house and
> then loose energy in the Iron and annihilate at around thermal energy.
> 
> From what I understand, the Penelope model is best for my geometrical
> setup and energy ranges.
> 
> As a first and basic validation of my simulation I looked at the
> penetration depth of the positron in the Iron.
> 
> Using both Penelope, LowEnergy and the Default model I got about 20
> micron, when I know that a reasonable result should be around the 100
> micron.
> 
> (give or take 30 is still fine)
> 
 I ran $G4INSTALL/examples/extended/electromagnetic/TestEm11 with the following macro :

 # $Id: orchen.mac,v 1.4 2006/09/18 17:26:20 maire Exp $
 #
 #
 /control/verbose 2
 /run/verbose 2
 #
 /testem/det/setMat Iron
 /testem/det/setSizeX  200 um
 /testem/det/setSizeYZ 200 um
 #
 /testem/phys/addPhysics  standard	# em physics
 #
 /run/initialize
 #
 /testem/phys/setCuts 1 um
 #
 /gun/particle e+
 /gun/energy 190 keV
 #
 /control/execute vis.mac
 /testem/event/drawTracks charged
 #
 /run/beamOn 100

Interactively, to see the tracks :
 PreInit> /control/execute orchen.mac

 On the output, you can read that the projected range of e+ is ~70 um 

 Cheers, Michel Maire

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1 Disagree: Re: highly un reasonable positron penetration depth in Fe. (LowEnergy, Penelope and default)   (Or Chen - 29 Jul, 2008)
1 None: Re: highly un reasonable positron penetration depth in Fe. (LowEnergy, Penelope and default)   (Or Chen - 29 Jul, 2008)
2 None: Re: highly un reasonable positron penetration depth in Fe. (LowEnergy, Penelope and default)   (michel maire - 30 Jul, 2008)
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