I have implemented transmission geometry into my new Rietveld program BGMN.
Dr. Kleeberg from Freiberg (kleeberg@mineral.tu-freiberg.de --- phone
+49 3731 39 3244) succesfully uses this feature for more than a year.
I don't know any about the STOE StadiP diffractometer. Dr. Kleeberg uses
a thin sample between 2 mylar foils (thickness 200...300 um), which is
used in transmission (rotated for about 90 degree in omega axis ->
transmission) and which rotates around the specimen normale for better
grain statistics. For this geometry, I use the same LP factor as for
Bragg-Brentano in reflection (including correction for secondary graphite
monochromator) plus an angle-dependent factor for absorption in specimen.
The absorption in the flat specimen must be predetermined with a simple,
additional measurement.
Much more complicated is the "capillary" geometry. I have implemented it
by computing an intensity correction by two fold integration over
specimen coordinates. But there are some known problems: homogenity of
specimen (no problem for "wires", but problem for true "capillaries"),
absorption coefficient of specimen. Nobody has used my implementation of
capillary geometry, until now.
J"org Bergmann
bergmann@rcs.urz.tu-dresden.de