[Gate-users] Re: Gate-users Digest, Vol 5, Issue 9

[D.J. van der Laan]

I do not think I completely understand what you mean. As far as I know
Geant4 does not limit the step size. The latest release has added this,
I think, but only for the multiple scattering processes, so I think this
will show up as a multiple scattering and not transport. But perhaps we
are talking about two different things.

I have used this trick in Geant4 to calculate fluencies through a
surface, and I have not noticed any transportation processes except on
volume boundaries.

The Gate hits file only has the volume id's of the volume in which the
interaction occurs, I do not know if this is the post or pre step point.
   So it is not possible to use this to detect 'real' boundary
crossings. Of course, it is possible to check if the interaction
position is on the surface of the volume.

Regards,

Jan



Chen, Yu wrote:
> 
> 
> I do not think "Transportation" process is only for the purpose
> of transporting between different volumes for particles.
> 
> Actually, a hit is a step in Geant4. When a particle travels more than
> a interaction range cut (defined as cut threshold) and if there is not
> a interaction (processes as compton, photoelectric etc) happened for this
> particle, then this step (hit) will be labled as "Transportation" process.
> 
> More accurate way to look for particles crossing a boundary is to find that
> step associated with prepoint in pre-volume and postpoint in post-volume.
> 
> Does GATE hit class have those volume names written out?
> 
> Please correct me if I am wrong and misleading. 
> 
> Yu Chen, Ph.D.
> University of Massachusetts Medical School
> Division of Nuclear Medicine
> 55 Lake Avenue North
> Worcester, MA 01655-0243
> Phone:  (508) 856-6123
> Fax:    (508) 856-4572
> 
> 

-- 
D.J. van der Laan
Delft University of Technology
Mekelweg 15, room 2.00.020
2629 JB Delft
The Netherlands

E: d.j.vanderlaan at tnw.tudelft.nl
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