Changes between Initial Version and Version 1 of Ticket #1086, comment 6


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Timestamp:
Mar 28, 2019 9:01:31 AM (5 years ago)
Author:
dirk
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  • Ticket #1086, comment 6

    initial v1  
    88 
    99For half-polarised SANS (SANSPOL) without spin-state discrimination after the sample (A=0 or out_spin=0.5, I^+^=uu+ud and I^-^=dd+du), you end up with the well known result: 
    10 I=N^2^ + '''Q'''.'''Q''' + '''P'''.(N* '''Q''' + N '''Q'''*) -i '''P'''.('''Q''' x '''Q'''*) and here the polarisation P not up_i appears as weight. 
     10I=N^2^ + '''Q'''.'''Q''' + '''P'''.(N* '''Q''' + N '''Q'''*) -i '''P'''.('''Q''' x '''Q'''*) and here the polarisation P not up_i appears as weight. But that is more a question how the scattering cross section is calculated. 
    1111 
    12 I have the feeling that the final spin-resolved scattering cross-section for non-perfect polariser and analyser is given by  
    13 I=1/(1+|A*P|)((1+A*P)*NSF+(1-A*P)*SF).  
     12That is another question, how to reparametrise the external field direction/Polarisation axis. 
    1413 
    15 The weights are hence not up_i and up_f but P=2 up_i -1 and A=2 up_f -1 and work on intensities not amplitudes.