bug in mosaic_simple/anisotropic?

[Kristian Nielsen]

> Date: Wed, 05 Apr 2000 10:20:11 +0200 (METDST)
> From: "Gonzalez, Miguel A." <gonzalez at ill.fr>

> tequila IN16/Partes> ./test5_mosaicsimple.linux --ncount=1000 eta=30 dif=0  
> Detector: moni1_I=1000 moni1_ERR=31.6228 moni1_N=1000
> Detector: moni5_I=1057.24 moni5_ERR=38.8623 moni5_N=991

Yes, this indeed looks wrong. I did some tests, and I found that the
problem arises when the algorithm considers scattering off crystal blocks
far out in the tails of the Gaussian mosaic curve (in your example this
happens for the vertical mosaic). I am not yet sure what the problem is,
but looking at the McStas manual (version 1.2), I think there may be a
problem with formula (5.18) and the sampling of phi from the double
mosaic width.

I will investigate further and get back to you when know more.

 - Kristian.

--
Kristian Nielsen        kristian.nielsen at risoe.dk
Risø National Laboratory
Condensed Matter Physics and Chemistry Department
Tel. +45 4677 5515   Fax +45 4677 4790
Encryption PGP key http://neutron.risoe.dk/kn.txt