The OPAL Discussion Forum

[Andreas Adelmann <andreas.adelmann AT psi.ch>]

Hello Suzie if the field extends beyond 2pi/42, the you can not use  
SYMMETRY=42.0.
Either you make a full map (2pi) or you add the fringe fields to the  
1/42 of the map.
Does that make sense?

Cheers Andreas



On 16.12.2011, at 16:01, Suzie Sheehy wrote:

> Hi there,
> I am trying to put together a ring which consists of 42 identical  
> cells.
>
> I have a polar co-ordinate field map which, rather than covering an  
> angle of 2pi/42, actually it extends beyond the 2pi/42 angle. In  
> this case I need to overlap the maps as I go around the full circle  
> of the ring and superimpose the fields to get the right overall  
> magnetic structure.
>
> The command in my input file looks like:
> ffag: Cyclotron, TYPE="CARBONCYCL", CYHARMON=1, PHIINIT=phi0,  
> PRINIT=pr0, RINIT=r0 , SYMMETRY=42.0, RFFREQ=fqrf,  
> FMAPFN="fmap_polar_opalformatted.dat", BSCALE=1.0;
>
> I was just wondering if this is correct, and if using 'symmetry'  
> actually takes into account overlapping maps to achieve the right  
> geometry or not?
>
> I can always superimpose the maps myself into a 360 degree map, but  
> was under the impression this should work automatically using the  
> 'symmetry' value? However, my initial tests indicate my assumption  
> might be wrong!
>
> Thanks,
> Suzie
>
>
> -----------------------------------------
> Suzie Sheehy
> Research Fellow and 2010 Brunel Fellow
> Royal Commission for the Exhibition of 1851
> ASTeC Intense Beams Group
> Rutherford Appleton Laboratory (R2, 403)
> Didcot, Oxon, OX11 0QX
> -----------------------------------------
> +44 (0)1235 446 782
> suzie.sheehy AT stfc.ac.uk
> www.suziesheehy.co.uk
> -----------------------------------------
>
>
>
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Best Andreas
------
Dr. sc. math. Andreas (Andy) Adelmann
Staff Scientist
Paul Scherrer Institut WLGB/132 CH-5232 Villigen PSI
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