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Forum: Fields: Magnetic and Otherwise
Re: None 'non-continous' electron trajectories (Dragos Constantin)
Date: 20 Mar, 2016
From: John Apostolakis <John Apostolakis>

Dear Dragos,

What you are seeing is an artifact of the tracking process in Geant4.  The field propagation is calculated first, which gives you a curved trajectory when ‘smooth’ trajectories are chosen.

At the end of a physics step, the correction for multiple scattering is applied - and this creates the kink which you observe.

John
===================================================
John Apostolakis,  EP Department, CERN

> On 18 Mar 2016, at 23:12, Dragos Constantin <dragos.constantin@gmail.com> wrote:
> 
> 
> *** Discussion title: Fields: Magnetic and Otherwise
> 
> Dear Colleagues,
> 
> I have a very simple program where I have defined a local constant
> magnetic field in a sub-volume. This volume is filled with air and I am
> generating 8 MeV electrons such that they could spiral and eventually
> they make it out of the magnetic volume. Most of the interaction points
> look fine but for some steps the electron decides to perform a sudden
> 'jump'. I have attached a screen capture to my message to see what I am
> talking about.
> 
> I have circled with black a secondary track which looks fine, and I have
> used red to circle some of these jumps which I think are not physical.
> What is going on here?
> 
> All I can tell is that there are no auxiliary points along the straight
> line where the jump is performed.
> 
> Thanks,
> 
> Dragos
> 
>   Attachment:
>      http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2016/03/18/15.10-42019-electron_trajectories.png
> 
> -------------------------------------------------------------
> Visit this GEANT4 at hypernews.slac.stanford.edu message (to reply or unsubscribe) at: 
> http://hypernews.slac.stanford.edu/HyperNews/geant4/get/emfields/240.html 

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1 None: Re: 'non-continous' electron trajectories   (Dragos Constantin - 21 Mar, 2016)
(_ None: Re: 'non-continous' electron trajectories   (John Apostolakis - 23 Mar, 2016)
(_ None: Re: 'non-continous' electron trajectories   (Dragos Constantin - 26 Mar, 2016)
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