[neutron-mc] Elastically bent perfect crystal as monochromator

[Willendrup, Peter Kj=?ISO-8859-1?B?5g==?=r]

Hello Anil,


On 2/18/07 11:34 AM, "ajain at barc.gov.in" <ajain at barc.gov.in> wrote:

>                I am using current version (McStas-1.10-i686-Win32.exe )of
> McStas for simulating an instrument for measuring residual stress .I wnat to
> know whether it is possible to use Elastically bent perfect crystal(silicon)
> as monochromator in the simulation and what is the process.

What you are describing here would certainly be very useful for the
community. However:

* We have no model of elastically bent crystals what so ever.
* The single crystal component (which includes secondary extinction but does
_not_ handle primary extinction if you need that?) would in principle be a
starting point. But, as recently reported by Aaron Percival
( http://mailman.risoe.dk/pipermail/neutron-mc/2007q1/000689.html ), there
are currently problems when trying to use it as a monochromator. (We are
currently debugging to investigate further).

If you decide to try to write your own component for your project, we would
certainly welcome it as a contribution to the project.


Best regards,

Peter Willendrup


--  
-----------------------------------------------
Peter Willendrup, MSc
Materials Research Department
Building 227
Risø National Laboratory
Technical University of Denmark
Frederiksborgvej 399
DK-4000 Roskilde
Denmark

Tel:  (+45) 4677 5862
Fax:  (+45) 4677 5758
Email: Peter.Willendrup at risoe.dk

-----------------------------------------------
>From 1 January 2007, Risø National Laboratory, the Danish Institute for
Food and Veterinary Research, the Danish Institute for Fisheries
Research, the Danish National Space Center and the Danish Transport
Research Institute have been merged with the Technical University of
Denmark (DTU) with DTU as the continuing unit.