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Forum: Geometry
Re: None holes in layers (Balint Radics)
Date: 05 Dec, 2012
From: John Apostolakis <John Apostolakis>

Dear Balint,

The most performant method for creating multiple holes in one volume is to create sub-volumes. You will have to fill them up with the material of the surroundings (or thin vacuum if relevant).

If you use this method, you can create as many sub-volumes as you like (within the memory of your machine) - the G4 geometry modeler will handle the navigation efficiently by creating an optimization grid ('smart voxels').

If your holes could go between different tubes, then there are two alternatives:

1) Manually place the hole volumes:
- locate yourself which volumes a hole is in ( it should be easy if your geometry is regular - and potentially you could get some help from the Navigator if not)
- if one hole H_k spans two or more tubes, then for each tube T_i in which it must appear, create a new volume S_i which is the intersection of T_i and the Hole H_k and subtract that (intersection) volume from the tube T_i;

2) Use the new capability of Geant4 9.5 (and 9.6) that allows you to create a "Layered Mass Geometry".  This allow you to superimpose new elements of a geometry (the holes) in the existing complicated geometry (the layers made of thin tubes)

Please search the documentation for information how to register a parallel geometry for this option.

I expect that these two options should be roughly competitive in simulation time, but the first option is the best tested one.  If you gain experience using the LMG and have feedback, we will be pleased to hear from you.

Best regards,
John 

On Dec 5, 2012, at 3:32 PM, Balint Radics wrote:

> *** Discussion title: Geometry
> 
> Hello,
> 
> I have some layers of G4Tubs tube thin objects. I would like to make small holes in it (e.g. 50 um size holes with 50 um distance from each other). Would you please give an example how to do that?
> 
> Thanks a lot,
> Balint 

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1 None: Re: holes in layers   (Balint Radics - 05 Dec, 2012)
(_ None: Re: holes in layers   (Michael H. Kelsey - 05 Dec, 2012)
(_ None: Re: holes in layers   (Balint Radics - 05 Dec, 2012)
(_ None: Re: holes in layers   (Balint Radics - 05 Dec, 2012)
(_ None: Re: holes in layers   (Michael H. Kelsey - 05 Dec, 2012)
(_ None: Re: holes in layers   (Balint Radics - 05 Dec, 2012)
(_ None: Re: holes in layers   (Balint Radics - 06 Dec, 2012)
(_ None: Re: holes in layers   (John Allison - 06 Dec, 2012)
(_ None: Re: holes in layers   (Balint Radics - 07 Dec, 2012)
1 None: Re: holes in layers   (Balint Radics - 07 Dec, 2012)
2 None: Re: holes in layers   (John Allison - 07 Dec, 2012)
1 None: Re: holes in layers   (Balint Radics - 07 Dec, 2012)
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