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## Electrons misteriously killed

Forum: Fields: Magnetic and Otherwise
Date: 14 Apr, 2014
From: Lafont Fabien <Lafont Fabien>

 Dear G4 users, I am facing some troubles with one of my computation. To have an idea of the Geometry, this is a basic scheme : A tub with r_min = 46*mm and r_max = 50*mm length= 1.2*m, filled with vaccum. There are also two end plates acting as detectors. Particle is killed when it travels in the wall of the tub All along this tub, exists a magnetic field (combination of a permanent octupole and some solenoids) computed from a BField map. The aim of the computation is to evaluate the percentage of electrons that reach the detectors before collide the wall. My problem comes from some electrons that are killed somewhere in the vaccum of the tub (this is actually the world volume), without having collided the wall or reached the detector. The log file from the computation mention for the Step Status the keyworld "Geom Limit" (Please see below) but I cannot understand why since the coordinates correspond only to the vaccum. Any idea of where might the problem come from ? Thanks a lot! Fabien log file : (It is exactly the same for the other processes and for PostSteopTo Do It >>AlongStepDoIt (process by process): Process Name = Transportation ++G4Step Information Address of G4Track : 0x34f80b40 Step Length (mm) : 13.75406869033371 Energy Deposit (MeV) : 0 ----------------------------------------------------------------------- StepPoint Information PreStep PostStep ----------------------------------------------------------------------- Position - x (mm) : 0.1 0.3154101134755054 Position - y (mm) : 0.1 10.9560293911734 Position - z (mm) : 0 8.126281846845105 Global Time (ns) : 0 0.05382331768428227 Local Time (ns) : 0 0.05382331768428227 Proper Time (ns) : 0 0.02814302915213434 Momentum Direct - x : 0.2986419395105249 -0.270870795845666 Momentum Direct - y : 0.7470567040047633 0.7705513030724732 Momentum Direct - z : 0.5939017367940016 0.5769572785668355 Momentum - x (MeV/c): 0.2487812638730343 -0.2256467361792115 Momentum - y (MeV/c): 0.6223295740435625 0.6419015606836007 Momentum - z (MeV/c): 0.4947450613874504 0.4806296168510689 Total Energy (MeV) : 0.9772813196679687 0.9772813196679687 Kinetic Energy (MeV): 0.4662824096679687 0.4662824096679687 Velocity (mm/ns) : 255.5410792588551 255.5410792588551 Volume Name : World World 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 ----------------------------------------------------------------------- !Note! Safety of PostStep is only valid after all DoIt invocations. ++G4ParticleChange Information

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1 Re: Electrons misteriously killed   (Lafont Fabien - 14 Apr, 2014)
1 Re: Electrons misteriously killed   (John Apostolakis - 14 Apr, 2014)
Re: Electrons misteriously killed   (Lafont Fabien - 16 Apr, 2014)
Re: Electrons misteriously killed   (John Apostolakis - 16 Apr, 2014)
Re: Electrons misteriously killed   (Gumplinger Peter - 16 Apr, 2014)
Re: Electrons misteriously killed   (John Apostolakis - 17 Apr, 2014)
2 Re: Electrons misteriously killed   (Gumplinger Peter - 14 Apr, 2014)
1 Re: Electrons misteriously killed   (Lafont Fabien - 15 Apr, 2014)
 to: "Electrons misteriously killed "
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