Message: Electric field and "local time goes back" issue Not Logged In (login)
 Next-in-Thread Next-in-Thread
 Next-in-Forum Next-in-Forum

None Electric field and "local time goes back" issue 

Forum: Fields: Magnetic and Otherwise
Re: None Mixed Electromagnetic field and ChordFinder (Francois Mauger)
Date: 23 Apr, 2015
From: Francois Mauger <Francois Mauger>

Hi all,

I have a Geant4 setup that implements a field with both magnetic and 
electric components.
I can activate on demand the electric field. Basically, my program compiles
and runs. I fire electrons of 1 MeV in STP air with a Bz magfield and Ey 
electric field.
However with the electric field activated I obtain random step errors 
like the following:

<pre>
...
*************************************************************
  Geant4 version Name: geant4-09-06-patch-01    (1-February-2013)
                       Copyright : Geant4 Collaboration
                       Reference : NIM A 506 (2003), 250-303
                             WWW : http://cern.ch/geant4
*************************************************************
...
[notice:virtual void mctools::g4::event_action::BeginOfEventAction(const 
G4Event*):171] Event #1
[notice:virtual void mctools::g4::event_action::BeginOfEventAction(const 
G4Event*):171] Event #2
[notice:virtual void mctools::g4::event_action::BeginOfEventAction(const 
G4Event*):171] Event #3
[notice:virtual void mctools::g4::event_action::BeginOfEventAction(const 
G4Event*):171] Event #4
[notice:virtual void mctools::g4::event_action::BeginOfEventAction(const 
G4Event*):171] Event #5
[notice:virtual void mctools::g4::event_action::BeginOfEventAction(const 
G4Event*):171] Event #6
[notice:virtual void mctools::g4::event_action::BeginOfEventAction(const 
G4Event*):171] Event #7
   G4ParticleChange::CheckIt    : the local time goes back  !! 
Difference:  0.14314337090688[ns]
e- E=0.0012850040011642 pos=0.011471222165611, -0.070632466275141, 
-0.097956932327808 global time=0.14314337090688 local time=0 proper time=0
   G4ParticleChange::CheckIt    : the proper time goes back  !! 
Difference:  0.14278431258136[ns]
e- E=0.0012850040011642 pos=0.011471222165611, -0.070632466275141, 
-0.097956932327808 global time=0.14314337090688 local time=0 proper time=0
       -----------------------------------------------
         G4ParticleChange Information
       -----------------------------------------------
         # of 2ndaries       :                    0
       -----------------------------------------------
         Energy Deposit (MeV):                    0
         Non-ionizing Energy Deposit (MeV):                    0
         Track Status        :                Alive
         True Path Length (mm) :               0.0313
         Stepping Control      :                    0
         Mass (GeV)   :                    0
         Charge (eplus)   :                    0
         MagneticMoment   :                    0
                 :  =                    0*[e hbar]/[2 m]
         Position - x (mm)   :                 11.5
         Position - y (mm)   :                -70.6
         Position - z (mm)   :                -97.9
         Time (ns)           :               -0.143
         Proper Time (ns)    :               -0.143
         Momentum Direct - x :               -0.428
         Momentum Direct - y :                0.721
         Momentum Direct - z :                0.545
         Kinetic Energy (MeV):              0.00129
         Velocity  (/c):               0.0708
         Polarization - x    :                    0
         Polarization - y    :                    0
         Polarization - z    :                    0
         Touchable (pointer) :            0x2511f90

-------- EEEE ------- G4Exception-START -------- EEEE -------
*** G4Exception : TRACK003
       issued by : G4ParticleChange::CheckIt
momentum, energy, and/or time was illegal
*** Event Must Be Aborted ***
-------- EEEE -------- G4Exception-END --------- EEEE -------

[notice:virtual void mctools::g4::event_action::BeginOfEventAction(const 
G4Event*):171] Event #8
[notice:virtual void mctools::g4::event_action::BeginOfEventAction(const 
G4Event*):171] Event #9
10 events have been kept for refreshing and/or reviewing.
Idle> exit
...
</pre>

I suspect something is wrong with the parameters passed to the G4 
field/chord/equation/stepper stuff
but I have no hint to understand the problem.
This problem does not occur with a pure magnetic field, only when an 
electric component is activated.

Thanks for help.

my system: G4.9.6 on Ubuntu 14.04LTS 64bits

Fran├žois Mauger
-- 

Inline Depth:
 1 1
 All All
Outline Depth:
 1 1
 2 2
 All All
Add message: (add)

1 None: Re: Electric field and "local time goes back" issue   (John Apostolakis - 24 Apr, 2015)
1 None: Re: Electric field and "local time goes back" issue   (Francois Mauger - 25 Apr, 2015)
2 None: Re: Electric field and "local time goes back" issue   (Francois Mauger - 25 Apr, 2015)
 Add Message Add Message
to: "Electric field and "local time goes back" issue"

 Subscribe Subscribe

This site runs SLAC HyperNews version 1.11-slac-98, derived from the original HyperNews


[ Geant 4 Home | Geant 4 HyperNews | Search | Request New Forum | Feedback ]