[gate-users] tracking of Compton e-

[Aurélien Vasseur]

Dear Gaters,

I'm working on Mac OS 10.3.8 with CLHEP1.8.2.0, GEANT4.6.2.p02 and GATE1.1.0.
I simulated a cylindricalPET system (with "bloc" as rsector, "cellule" as submodule and "liqXe" as crystal) and a point as source with backtoback gamma (511keV, monoenergy, isotropic emission) at 20 Bq.
I set LowEnergy for Compton and photoelectric effects and I inactivated Rayleigh effect. I set 1m for ElectronCut and 1 GeV for XRayCut.

I obtained, e.g. on the event #6:

*********************************************************************************************************
* G4Track Information:   Particle = gamma,   Track ID = 2,   Parent ID = 0
*********************************************************************************************************

Step#    X(mm)    Y(mm)    Z(mm) KinE(MeV)  dE(MeV) StepLeng TrackLeng  NextVolume ProcName
    0        0        0        0     0.511        0        0         0     world_P initStep
    1     -171     -246     -132     0.511        0      328       328 cylindricalPET_P Transportation
    2     -174     -250     -134     0.511        0      5.2       333     inWin_P Transportation
    3     -175     -252     -135     0.511        0     2.22       335   PCBsupp_P Transportation
    4     -176     -253     -136     0.511        0     1.11       336   PCBkapt_P Transportation
    5     -176     -253     -136     0.511        0    0.389       337 PCBcopper_P Transportation
    6     -176     -253     -136     0.511        0   0.0888       337     liqXe_P Transportation
    7     -181     -260     -140     0.511        0     9.43       346      bloc_P Transportation
    8     -182     -261     -140     0.475        0     1.22       348      bloc_P LowEnCompton
    :----- List of 2ndaries - #SpawnInStep=  1(Rest= 0,Along= 0,Post= 1), #SpawnTotal=  1 ---------------
    :      -182      -261      -140    0.0358                 e-
    :----------------------------------------------------------------- EndOf2ndaries Info ---------------
    9     -182     -261     -140     0.475        0   0.0939       348     liqXe_P Transportation
   10     -185     -270     -141     0.475        0     9.37       357      bloc_P Transportation
   11     -185     -270     -141     0.333        0    0.501       358      bloc_P LowEnCompton
    :----- List of 2ndaries - #SpawnInStep=  1(Rest= 0,Along= 0,Post= 1), #SpawnTotal=  2 ---------------
    :      -185      -270      -141     0.143                 e-
    :----------------------------------------------------------------- EndOf2ndaries Info ---------------
   12     -185     -270     -141     0.333        0    0.332       358     liqXe_P Transportation
   13     -184     -272     -140     0.333        0     2.35       360      bloc_P Transportation
   14     -183     -273     -140     0.333        0      1.4       362     liqXe_P Transportation
   15     -181     -277     -138     0.287   0.0453     4.16       366     liqXe_P LowEnCompton
   16     -179     -278     -138     0.287        0     2.54       368      bloc_P Transportation
   17     -179     -278     -138     0.287        0     0.54       369     liqXe_P Transportation
   18     -171     -281     -138         0   0.0346     7.97       377     liqXe_P LowEnPhotoElec
    :----- List of 2ndaries - #SpawnInStep=  1(Rest= 0,Along= 0,Post= 1), #SpawnTotal=  3 ---------------
    :      -171      -281      -138     0.253                 e-
    :----------------------------------------------------------------- EndOf2ndaries Info ---------------

Could someone explain me why Compton e- of step #11 was generated and tracked, and no one of step #15? Thanks in advance.

Aurelien Vasseur

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