The problem of falsified counting statistics (deviating from Poisson
distribution) sometimes arises even from (wrong) conversion of 0D
detector data (typically when originally cps have been stored and the
counting time got lost in the conversion), and is quite common when 1D
detector data are
If this rule is broken, such as the mode in
FIT2D that smooths patterns by pixel-splitting) then one introduces
correlation between points in the pattern
Hi Brian, your comment has triggered me it seems :-)
For SAXS and PDF it could be better to under-sample the data (see end),
but for
Tony. If you want the statistics to be the same as for larger steps you
should be adding the counts from your PSD channels, not averaging them.
That said, with an x-ray PSD you perhaps have so much intensity that
uncertainties in your refined parameters due to counting statistics may be
small
Hi Tony
If you want to have a look at what the uncertainties are doing, then try
scanning over a peak a couple of dozen times (maybe with a few different mA
settings on the tube, maybe with some different step times) to collect a
range of different intensities. The standard deviation of the "raw"
Hi Tony
>My I ask is this re-bined data from the measurement software considered as
"raw data" or "treated data"?
I'm not sure what is meant by treated data. Almost all neutron data and
synchrotron data with area detectors are "treated data".
If the detector has a slit width in the
Tony,
These days many if not most powder instruments (~100% of those at
synchrotron and neutron sources) do some sort of data processing to take raw
measurements and convert them to diffractograms that are used in Rietveld. The
key for how to know if this is done properly is to ask if any
Hello,
the term "raw data" has become kind of fuzzy in recent times. Most
powder diffractometers nowadays are equipped with some kind of linear or
area detector. The 1D powder pattern in this case is always the result
of some integration, merging, and binning.
I would take "raw" to mean
Tony, if you bin (add) the raw data you can perform Rietveld refinement as
if you had taken larger steps.
Regards, Alan.
On Thu, 26 Sep 2019 at 05:42, iangie wrote:
> Dear Rietvelder,
>
> I hope you are doing well.
> It is generally acknolwdged that Rietveld refinement should be performed
> on
