Dear All,

In this scenario, which should be the number for LP in Topas if ones has a
D8 with a primary monochromator for pure CuKalpha1?

thanks for the response,

angel l. ortiz

>
> Dear Peter,
>
> Of course the LP correction can't be sample-dependent and for your
> configuration LP=0 should be Ok for all samples. It seems that you have an
> intensity loss at high-angles that may be partly compensated by LP=90.
> Possible reason may be in a misalignment of the anti-scattering slits or
> screen (knife) if you use them.
>
> Best regards,
> Leonid
>
> *******************************************************
>  Leonid A. Solovyov
>  Institute of Chemistry and Chemical Technology
>  660049, K. Marx 42, Krasnoyarsk , Russia
>  www.icct.ru/eng/content/persons/Sol_LA
>  www.geocities.com/l_solovyov
> *******************************************************
>
> --- On Thu, 7/23/09, Peter Y. Zavalij <pzava...@umd.edu> wrote:
>
> From: Peter Y. Zavalij <pzava...@umd.edu>
> Subject: RE: LP factor in the Rietveld refinement
> To: rietveld_l@ill.fr
> Date: Thursday, July 23, 2009, 4:52 AM
>
> Well... the situation with LP is not so simple. Using TOPAS for refinement
> data collected on D8 advance with Ni-filter and LynxEye detector I observe
> the following:
> - For all samples LP=0 is OK and gives the best fit as it should be by the
> book.
> - HOWEVER for LaB6 standard LP=0 yields very poor fit for several high
> angle
> reflections (>120 deg. 2theta) while LP=90 gives perfect fit. The
> difference
> in R factors 12% and 4% cannot be simply ignored...
>
> Can anyone explain this?
>
>
> Peter Zavalij 
>
> X-ray Crystallographic Center
> University of Maryland
> College Park, MD
>
> Office: (301)405-1861
> Lab: (301)405-3230
> Fax: (301)314-9121
>
>
>
>
>



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