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Forum: Geometry
Date: 18 Oct, 2012
From: Steve Asztalos <Steve Asztalos>


I am modeling the response of a Phoswich detector where an electron is detected in a low-Z scintillator region (a hollow cylinder filled with Xe gas possessing thin BC-404 walls) cylindrically surrounded by a high-Z scintillator for capturing gammas (concentric cylinders with a Xe gas in hole at the center running the entire length).

My code produces reasonable output, with one exception: the source description is not what I expect it to be. Namely, I have a defined my source such that I would expect it to be uniformly distributed within the confines of my hollow inner scintillator region, viz

 G4VSolid* solidSource = new G4Tubs("solidSource", 0., fInnerScinRadius - fInnerScinThickness, fOuterScinHalfz, 0., twopi);
  logicSource = new G4LogicalVolume(solidSource ,SourceMatter, "logicSource",0,0,0);
  physiSource = new G4PVPlacement(0, positionInnerScintillator, logicSource, "Radioactive source", logicWorld, false, 0);  

 UI->ApplyCommand("/gps/pos/confine Radioactive source"); 

but when I run the program (using below) my source is emitting isotropically but confined to a point at the center of my detector - not uniformly over the source volume.

I've tried all sorts of permutations with no relief. Any insight as to where I am missing the boat?

As always, much appreciated

Steve Asztalos


/event/fileName Xe133test /event/ionType Xe133m

# Should match number of event to run /event/numberEventsPrint 10


# ----------------------
# Visualization settings

#/vis/open HepRepFile

/vis/open OGLIX /vis/viewer/set/style wireframe # Set direction from target to camera. /vis/viewer/set/viewpointVector 10.7 1. 1. /vis/viewer/set/viewpointThetaPhi 90 180 deg /vis/viewer/zoom 1. /vis/scene/create /vis/scene/add/volume /vis/sceneHandler/attach /vis/drawVolume /vis/viewer/flush

/vis/scene/add/trajectories /vis/scene/endOfEventAction accumulate

/vis/modeling/trajectories/create/drawByParticleID /vis/modeling/trajectories/drawByParticleID-0/set gamma green /vis/modeling/trajectories/drawByParticleID-0/set e- red /vis/modeling/trajectories/drawByParticleID-0/set opticalphoton white # ----------------------

#/tracking/verbose 1

/gps/source/intensity 1.0 /gps/particle ion /gps/ion 54 133 0 0

#/gps/energy 30 keV 
#/gps/ang/type iso
#/gps/particle e-

/run/beamOn 100


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1 None: Re: Source volume restriction   (Steve Asztalos - 19 Oct, 2012)
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