[mcstas-users] Pol_simpleBfield : wrong intensity(?)

[Erik B Knudsen]

Dear Andre and others,

I can confirm this irregular behaviour on my linux system with a McStas 
2.1. I have therefore opened a ticket on the matter in our bug-tracking 
system, and will investigate the matter further asap. Please stay tuned.

cheers
Erik

On 02/03/15 13:43, André Kusmin wrote:
> Hi everyone,
>
> I noticed that in a simple polarized neutron instrument
> made of source, polarizer, precession field, analyzer
> the resulting signal, as expected, oscillates as cos(const*lambda*B*L)
> but at B=0, the intensity of the signal is less than 100% (see attached
> PNG, plotted intensity against two different lengths of magnetic field
> regions).
>
> It turns out that intensity at B*L=0 is correct.
>
> For 100 % polarized beam and zero precession field  the intensity after
> the analyzer is 4.2e-14
> (with TestLarmor.out)
> The same intensity I get with ./TestLarmorOnlysource.out
> but when I set non zero field in precession region I get even larger
> intensity, which is impossible.
>
> Test can be done with two  attached  instr files and commands:
>
> ./TestLarmor.out By1=0  -n 1e5  DLambda=0.000001
> ./TestLarmor.out By1=0.000001  -n 1e5   DLambda=0.000001
> ./TestLarmorOnlysource.out   -n 1e5   DLambda=0.000001
>
> could anyone please check if this is reproducible?
> perhaps I miss something.
>
> I have McStas pre2.2 (compiled from SVN) on linux multilib 64 bit
> (Slackware)
>
>
> best regards
> Andre
>
>
>
>
>
> _______________________________________________
> mcstas-users mailing list
> mcstas-users at mcstas.org
> http://mailman.mcstas.org/cgi-bin/mailman/listinfo/mcstas-users
>

-- 
Erik Bergbäck Knudsen, Research Engineer         | DTU | morituri
NEXMAP, DTU Fysik, DK-2800 Kgs. Lyngby, Denmark  |<>-<>|    te
phone: (+45) 2132 6655                           |<>-<>| salutant