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Forum: Geometry
Re: Question Tracking problem with policapillary tubes and tori (Alexey Tkachenko)
Re: Feedback Re: Tracking problem with policapillary tubes and tori (Gumplinger Peter)
Date: 25 May, 2006
From: Alexey Tkachenko <ayut@hea.iki.rssi.ru>

Peter,

Yes. You are right. The Navigator does not see the boundary of channel for an unknown reason.

I run our program with /tracking/verbose/ level set to 4. The detailed tracking information you may see below. For simplicity I have slightly shifted the position of gun. Now it is placed at the center of channel. The distance between gun and the top of the channel is 0.1 mm. The gun is declined at the angle 1 arc.min. to the Z axis in the XZ plane.

The position of center of testing channel is x=0.2211 mm; y=0.0. The channel radius is 0.01 mm.

The momentum is really reversed after step 2 and the gamma position coincides with position of boundary. But the Navigator does not make the zero length step at the boundary on the step 3.

*********************************************************************************************************
* G4Track Information:   Particle = gamma,   Track ID = 1,   Parent ID = 0
*********************************************************************************************************
Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    0    221 mum     0 fm     70 cm     20 keV     0 eV      0 fm      0 fm        World    initStep
 **PostStepDoIt (after all invocations):
    ++List of invoked processes 
      1) Transportation
      2) GammaBoundary
      3) phot (Forced)

    ++G4Step Information 
      Address of G4Track    : 0x84e4c70
      Step Length (mm)      : 0.1000000042308204
      Energy Deposit (MeV)  : 0
      -----------------------------------------------------------------------
        StepPoint Information               PreStep            PostStep
      -----------------------------------------------------------------------
         Position - x (mm)   :               0.2211   0.221129088821687
         Position - y (mm)   :                    0                   0
         Position - z (mm)   :                700.1                 700
         Global Time (ns)    :                    00.0003335641093106497
         Local Time (ns)     :                    00.0003335641093106497
         Proper Time (ns)    :                    0                   0
         Momentum Direct - x : 0.00029088820456342460.0002908882045634246
         Momentum Direct - y :                    0                   0
         Momentum Direct - z :  -0.9999999576920253 -0.9999999576920253
         Momentum - x (MeV/c): 5.817764091268492e-065.817764091268492e-06
         Momentum - y (MeV/c):                    0                   0
         Momentum - z (MeV/c): -0.01999999915384051-0.01999999915384051
         Total Energy (MeV)  :                 0.02                0.02
         Kinetic Energy (MeV):                 0.02                0.02
         Velocity (mm/ns)    :           299.792458          299.792458
         Volume Name         :                World         Fiber_holes
         Safety (mm)         :                    0                   0
         Polarization - x    :                    0                   0
         Polarization - y    :                    0                   0
         Polarization - Z    :                    0                   0
         Weight              :                    1                   1
         Step Status         :            Undefined          Geom Limit
         Process defined Step:            Undefined      Transportation
      -----------------------------------------------------------------------
#Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    1    221 mum     0 fm     70 cm     20 keV     0 eV    100 mum   100 mum       World  Transportation
 **PostStepDoIt (after all invocations):
    ++List of invoked processes 
      1) Transportation
      2) GammaBoundary
      3) phot (Forced)

    ++G4Step Information 
      Address of G4Track    : 0x84e4c70
      Step Length (mm)      : 34.27746818554761
      Energy Deposit (MeV)  : 0
      -----------------------------------------------------------------------
        StepPoint Information               PreStep            PostStep
      -----------------------------------------------------------------------
         Position - x (mm)   :    0.221129088821687  0.2310999999991609
         Position - y (mm)   :                    0                   0
         Position - z (mm)   :                  700   665.7225332646626
         Global Time (ns)    : 0.0003335641093106497   0.114670890719267
         Local Time (ns)     : 0.0003335641093106497   0.114670890719267
         Proper Time (ns)    :                    0                   0
         Momentum Direct - x : 0.0002908882045634246-0.0002908882045634246
         Momentum Direct - y :                    0                  -0
         Momentum Direct - z :  -0.9999999576920253  0.9999999576920253
         Momentum - x (MeV/c): 5.817764091268492e-06-5.817764091268492e-06
         Momentum - y (MeV/c):                    0                  -0
         Momentum - z (MeV/c): -0.01999999915384051 0.01999999915384051
         Total Energy (MeV)  :                 0.02                0.02
         Kinetic Energy (MeV):                 0.02                0.02
         Velocity (mm/ns)    :           299.792458          299.792458
         Volume Name         :          Fiber_holes         Klens_fiber
         Safety (mm)         :                    0                   0
         Polarization - x    :                    0                  -0
         Polarization - y    :                    0                  -0
         Polarization - Z    :                    0                  -0
         Weight              :                    1                   1
         Step Status         :           Geom Limit          Geom Limit
         Process defined Step:       Transportation      Transportation
      -----------------------------------------------------------------------
#Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    2    231 mum     0 fm   66.6 cm     20 keV     0 eV   3.43 cm   3.44 cm   Fiber_holes  Transportation
 **PostStepDoIt (after all invocations):
    ++List of invoked processes 
      1) Transportation
      2) GammaBoundary
      3) phot (Forced)

    ++G4Step Information 
      Address of G4Track    : 0x84e4c70
      Step Length (mm)      : 0.005773263875793082
      Energy Deposit (MeV)  : 0.015861
      -----------------------------------------------------------------------
        StepPoint Information               PreStep            PostStep
      -----------------------------------------------------------------------
         Position - x (mm)   :   0.2310999999991609  0.2310983206247976
         Position - y (mm)   :                    0                   0
         Position - z (mm)   :    665.7225332646626   665.7283065282942
         Global Time (ns)    :    0.114670890719267  0.1146901482546777
         Local Time (ns)     :    0.114670890719267  0.1146901482546777
         Proper Time (ns)    :                    0                   0
         Momentum Direct - x : -0.0002908882045634246-0.0002908882045634246
         Momentum Direct - y :                   -0                  -0
         Momentum Direct - z :   0.9999999576920253  0.9999999576920253
         Momentum - x (MeV/c): -5.817764091268492e-06                  -0
         Momentum - y (MeV/c):                   -0                  -0
         Momentum - z (MeV/c):  0.01999999915384051                   0
         Total Energy (MeV)  :                 0.02                   0
         Kinetic Energy (MeV):                 0.02                   0
         Velocity (mm/ns)    :           299.792458          299.792458
         Volume Name         :          Klens_fiber         Klens_fiber
         Safety (mm)         :                    00.0001016793752024268
         Polarization - x    :                   -0                   0
         Polarization - y    :                   -0                   0
         Polarization - Z    :                   -0                   0
         Weight              :                    1                   1
         Step Status         :           Geom Limit       PostStep Proc
         Process defined Step:       Transportation                phot
      -----------------------------------------------------------------------
#Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    3    231 mum     0 fm   66.6 cm      0 eV   15.9 keV  5.77 mum  3.44 cm   Klens_fiber        phot
Track (trackID 1, parentID 0) is processed with stopping code 2
A new track 0x84e4d18 (trackID 2, parentID 1) is passed to G4StackManager.
### pop requested out of 1 stacked tracks.
Selected G4StackedTrack : 0x854af48 with G4Track 0x84e4d18 (trackID 2, parentID 1)
Track 0x84e4d18 (trackID 2, parentID 1) is passed to G4TrackingManager.
----------------------------------------------------------------------------------------------

For further testing I sent the gamma along the normal at the boundary of channel after reflection (step 2). But the Navigator did not find my channel again and gamma is absorbed.

*******************************************************************************
*******************************************************************************
 **PostStepDoIt (after all invocations):
    ++List of invoked processes 
      1) Transportation
      2) GammaBoundary
      3) phot (Forced)

    ++G4Step Information 
      Address of G4Track    : 0x84e4c30
      Step Length (mm)      : 34.27746818554761
      Energy Deposit (MeV)  : 0
      -----------------------------------------------------------------------
        StepPoint Information               PreStep            PostStep
      -----------------------------------------------------------------------
         Position - x (mm)   :    0.221129088821687  0.2310999999991609
         Position - y (mm)   :                    0                   0
         Position - z (mm)   :                  700   665.7225332646626
         Global Time (ns)    : 0.0003335641093106497   0.114670890719267
         Local Time (ns)     : 0.0003335641093106497   0.114670890719267
         Proper Time (ns)    :                    0                   0
         Momentum Direct - x : 0.0002908882045634246                  -1
         Momentum Direct - y :                    0                  -0
         Momentum Direct - z :  -0.9999999576920253                  -0
         Momentum - x (MeV/c): 5.817764091268492e-06               -0.02
         Momentum - y (MeV/c):                    0                  -0
         Momentum - z (MeV/c): -0.01999999915384051                  -0
         Total Energy (MeV)  :                 0.02                0.02
         Kinetic Energy (MeV):                 0.02                0.02
         Velocity (mm/ns)    :           299.792458          299.792458
         Volume Name         :          Fiber_holes         Klens_fiber
         Safety (mm)         :                    0                   0
         Polarization - x    :                    0                  -1
         Polarization - y    :                    0                  -0
         Polarization - Z    :                    0                  -0
         Weight              :                    1                   1
         Step Status         :           Geom Limit          Geom Limit
         Process defined Step:       Transportation      Transportation
      -----------------------------------------------------------------------
#Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    2    231 mum     0 fm   66.6 cm     20 keV     0 eV   3.43 cm   3.44 cm   Fiber_holes  Transportation
 **PostStepDoIt (after all invocations):
    ++List of invoked processes 
      1) Transportation
      2) GammaBoundary
      3) phot (Forced)

    ++G4Step Information 
      Address of G4Track    : 0x84e4c30
      Step Length (mm)      : 0.005773263875793082
      Energy Deposit (MeV)  : 0.015861
      -----------------------------------------------------------------------
        StepPoint Information               PreStep            PostStep
      -----------------------------------------------------------------------
         Position - x (mm)   :   0.2310999999991609  0.2253267361233678
         Position - y (mm)   :                    0                   0
         Position - z (mm)   :    665.7225332646626   665.7225332646626
         Global Time (ns)    :    0.114670890719267  0.1146901482546777
         Local Time (ns)     :    0.114670890719267  0.1146901482546777
         Proper Time (ns)    :                    0                   0
         Momentum Direct - x :                   -1                  -1
         Momentum Direct - y :                   -0                  -0
         Momentum Direct - z :                   -0                  -0
         Momentum - x (MeV/c):                -0.02                  -0
         Momentum - y (MeV/c):                   -0                  -0
         Momentum - z (MeV/c):                   -0                  -0
         Total Energy (MeV)  :                 0.02                   0
         Kinetic Energy (MeV):                 0.02                   0
         Velocity (mm/ns)    :           299.792458          299.792458
         Volume Name         :          Klens_fiber         Klens_fiber
         Safety (mm)         :                    00.002554458450100438
         Polarization - x    :                   -1                  -2
         Polarization - y    :                   -0                   0
         Polarization - Z    :                   -0                   0
         Weight              :                    1                   1
         Step Status         :           Geom Limit       PostStep Proc
         Process defined Step:       Transportation                phot
      -----------------------------------------------------------------------
#Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    3    225 mum     0 fm   66.6 cm      0 eV   15.9 keV  5.77 mum  3.44 cm   Klens_fiber        phot
----------------------------------------------------------------------------------------------

It is substantial that such effect may be observed only for complicate geometry with rather big number of channels. If I take only this one channel in the fiber the reflection is working properly. For the central channel the reflection is working properly for any configuration.

Alexey

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1 None: Re: Tracking problem with policapillary tubes and tori   (Makoto Asai - 25 May, 2006)
(_ Feedback: Re: Tracking problem with policapillary tubes and tori   (Alexey Tkachenko - 25 May, 2006)
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