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Warning Problem(bug?) with SubtractionSolid and Boundary process 

Forum: Processes Involving Optical Photons
Date: 19 Mar, 2010
From: <n9-mr@mail.ru>

Hello.
I found strange action in simulation of optical processes.
If I use G4SubtractionSolid
*********
G4Ellipsoid* solidConoBox= new G4Ellipsoid("OM1ConoBox",12.5*cm,12.5*cm,6.*cm,-4.3*cm,0.0*cm);
  G4Ellipsoid* solidConoBoxAir= new G4Ellipsoid("OM1ConoBoxAir",12.4*cm,12.4*cm,6.*cm,-4.4*cm,0.1*cm);
G4SubtractionSolid* subtractionConoBox = new G4SubtractionSolid("OM1ConoBox", solidConoBox, solidConoBoxAir, 0, 0);
  G4LogicalVolume* logicCono4 = new G4LogicalVolume(subtractionConoBox,materialsManager->GetMaterial("Glass"),"OM1ConoBox");
****
than I have
*********************************************************************************************************
* G4Track Information:   Particle = opticalphoton,   Track ID = 1,   Parent ID = 0
*********************************************************************************************************

Step#    X(mm)    Y(mm)    Z(mm) KinE(MeV)  dE(MeV) StepLeng TrackLeng  NextVolume ProcName
    0        0       50      575  2.38e-06        0        0         0      Target initStep
 Photon at Boundary!
 Old Momentum Direction: (0,0,-1)
 Old Polarization:       (-1,0,0)
 New Momentum Direction: (0,0,-1)
 New Polarization:       (-1,0,-0)
 *** FresnelRefraction ***
    1        0       50      157  2.38e-06        0      418       418       OM1_2 Transportation
 Photon at Boundary!
 Old Momentum Direction: (0,0,-1)
 Old Polarization:       (-1,0,0)
 New Momentum Direction: (0,-0.9607882364709412,0.2772831849554869)
 New Polarization:       (1,-0,0)
 *** SpikeReflection ***
    2        0       50    -12.5  2.38e-06        0      170       588     OM1Cono Transportation
    3        0       50    -12.5  2.38e-06        0        0       588       OM1_2 Transportation
 Photon at Boundary!
 Old Momentum Direction: (0,-0.9607882364709412,0.2772831849554869)
 Old Polarization:       (1,0,0)
 New Momentum Direction: (0,-0.1359630226747735,0.9907139125222473)
 New Polarization:       (-1,0,0)
 *** SpikeReflection ***
    4        0     -114     34.9  2.38e-06        0      171       759 OM1ConoBox1 Transportation
 Photon at Boundary!
 Old Momentum Direction: (0,-0.1359630226747735,0.9907139125222473)
 Old Polarization:       (-1,0,0)
 New Momentum Direction: (0,-0.1998656433319171,0.9798233129577592)
 New Polarization:       (-1,0,0)
 *** FresnelRefraction ***
    5        0     -118     58.1  2.38e-06        0     23.4       782       OM1_2 Transportation
 Photon at Boundary!
 Old Momentum Direction: (0,-0.1998656433319171,0.9798233129577592)
 Old Polarization:       (-1,0,0)
 New Momentum Direction: (0,-0.1998656433319171,0.9798233129577592)
 New Polarization:       (-1,0,0)
 *** FresnelRefraction ***
    6        0     -127      105  2.38e-06        0     48.1       830      Target Transportation
 Photon at Boundary!
 Old Momentum Direction: (0,-0.1998656433319171,0.9798233129577592)
 Old Polarization:       (-1,0,0)
 New Momentum Direction: (0,-0.1998656433319171,0.9798233129577592)
 New Polarization:       (-1,0,0)
 *** FresnelRefraction ***
    7        0     -616  2.5e+03  2.38e-06        0 2.44e+03  3.27e+03       World Transportation
    8        0     -616  2.5e+03  2.38e-06        0     2.55  3.28e+03  OutOfWorld Transportation
***********************
Note, that step#3 has steplength=0, but step#5 has steplength!=0.
It is picture http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2010/03/19/13.10-42700-Wired_View_1.gif

If I change subtraction solid to *************************** G4Cons* subtractionConoBox = new G4Cons("OM1ConoBox",8.67*cm,8.77*cm,12.67*cm,12.77*cm,4.1*cm,0.,2*pi); ********** than

*********************************************************************************************************
* G4Track Information:   Particle = opticalphoton,   Track ID = 1,   Parent ID = 0
*********************************************************************************************************

Step#    X(mm)    Y(mm)    Z(mm) KinE(MeV)  dE(MeV) StepLeng TrackLeng  NextVolume ProcName
    0        0      100      575  2.38e-06        0        0         0      Target initStep
 Photon at Boundary! 
 Old Momentum Direction: (0,0,-1)
 Old Polarization:       (-1,0,0)
 New Momentum Direction: (0,0,-1)
 New Polarization:       (-1,0,-0)
 *** FresnelRefraction *** 
    1        0      100      131  2.38e-06        0      444       444       OM1_2 Transportation
 Photon at Boundary! 
 Old Momentum Direction: (0,0,-1)
 Old Polarization:       (-1,0,0)
 New Momentum Direction: (0,-0.9993867442208462,0.03501621732364892)
 New Polarization:       (1,-0,0)
 *** SpikeReflection *** 
    2        0      100    -1.34  2.38e-06        0      133       576 OM1ConoBox1 Transportation
    3        0      100    -1.34  2.38e-06        0        0       576       OM1_2 Transportation
 Photon at Boundary! 
 Old Momentum Direction: (0,-0.9993867442208462,0.03501621732364892)
 Old Polarization:       (1,0,0)
 New Momentum Direction: (0,0.3729098066277166,0.9278675962231244)
 New Polarization:       (-1,0,0)
 *** SpikeReflection *** 
    4        0    -50.3     3.93  2.38e-06        0      150       727     OM1Cono Transportation
    5        0    -50.3     3.93  2.38e-06        0        0       727       OM1_2 Transportation
 Photon at Boundary! 
 Old Momentum Direction: (0,0.3729098066277166,0.9278675962231244)
 Old Polarization:       (-1,0,0)
 New Momentum Direction: (0,0.3729098066277166,0.9278675962231244)
 New Polarization:       (-1,0,0)
 *** FresnelRefraction *** 
    6        0     14.2      164  2.38e-06        0      173       900      Target Transportation
 Photon at Boundary! 
 Old Momentum Direction: (0,0.3729098066277166,0.9278675962231244)
 Old Polarization:       (-1,0,0)
 New Momentum Direction: (0,0.3729098066277166,0.9278675962231244)
 New Polarization:       (-1,0,0)
 *** FresnelRefraction *** 
    7        0      953  2.5e+03  2.38e-06        0 2.52e+03  3.42e+03       World Transportation
    8        0      954  2.5e+03  2.38e-06        0     2.69  3.42e+03  OutOfWorld Transportation

Note, that step#3 and step#5 has steplength=0 and there is no refraction at vitrual boundary between air inside G4Cons and air outside. It is picture http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2010/03/19/13.10-65347-Wired_View_2.gif

Optical surface definition:
**********
G4OpticalSurface* our_Mirror_opsurf =  new G4OpticalSurface("OM1Mirror_opsurf");
  our_Mirror_opsurf->SetFinish(polishedfrontpainted); // needed for mirror
  our_Mirror_opsurf->SetModel(glisur); 
  our_Mirror_opsurf->SetType(dielectric_dielectric);
  our_Mirror_opsurf->SetPolish(0.999);              // a guess -- FIXME
  G4MaterialPropertiesTable* propMirror= new G4MaterialPropertiesTable();
  propMirror->AddProperty("REFLECTIVITY", new G4MaterialPropertyVector());
  propMirror->AddEntry("REFLECTIVITY", 2.034*eV, 0.9999);
  propMirror->AddEntry("REFLECTIVITY", 4.136*eV, 0.9999);
  our_Mirror_opsurf->SetMaterialPropertiesTable( propMirror );
  G4LogicalBorderSurface* MirrorSurface = new G4LogicalBorderSurface("OM1Mirror",physiOM1_2,physiCono4,our_Mirror_opsurf);
**********
physiOM1_2 it is mother volume for PMT, it is sphere filled by air.

geant4 version is Patch4.9.1-2.

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1 Feedback: Re: Problem(bug?) with SubtractionSolid and Boundary process   (Gumplinger Peter - 19 Mar, 2010)
(_ None: Re: Problem(bug?) with SubtractionSolid and Boundary process   (n9-mr@mail.ru - 20 Mar, 2010)
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