[mcstas-users] mcstas-users Digest, Vol 22, Issue 1

[Peter Willendrup]

Hello Genoveva,


Sorry for the delay in responding. 

The way I understand surface imperfections, two effects are typically talked about:

Roughness - corresponding to microscopic de-placement/misalignment of surface atoms. As far as I understand, this will effectively correspond a change in the slope of the reflectivity-curve, modeled by the alpha-parameter of the guide components. 

Wavyness - longer length-scale surface effects arising from manufacturing of the mirrors, typically variation that occurs in the cm-m range. Both the Guide_wavy and Guide_gravity components implement a phenomenological description of this effect by emitting outgoing neutrons within a gaussian 'cone'. I think Kaspar Klenø from University of Copenhagen has worked a bit at wavyness lately, putting him cc: so that you can contact him directly if interested?


Best regards,

Peter Willendrup

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Peter Willendrup - Development engineer

RISØ DTU
Materials Research Division
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On 20/01/2011, at 13.11, Genoveva Burca wrote:

> mcstas-users at mcstas.org writes:
> Can you provide a little more information.
> 
> What sort of super mirror arrangement are you trying to model?
> 
> Are you interested in the performance of a long guide system or a smaller device such as a polariser?
> 
> Best regards
> 
> Robert
> 
> 
> 
> Hi Robert,
> 
> Thank you very much for your reply.
> 
> I'm interested in the performance of a long guide system (my project includes modelling the passage of neutrons along supermirror guides.)
> 
> Best wishes,
> 
> Genoveva
> 
> 
> -- 
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