As Mike implies, for a given counting time, you have much better
statistics using the high intensity configuration. This can be true even
when the signal to noise ratio is actually lower with the high intensity
configuration. So signal/noise is not everything.
That said, there is no point in reducing statistical error much below
systematic error. I would try hard to physically model the peak asymmetry
using a higher intensity configuration, and for a given counting time try
to balance statistical error with systematic error, which occurs when the
model cannot completely describe the data however you choose the model
parameters.
Many theoretical arguments about signal/noise forget that the
experimentalist has a finite time to collect his data :-)
Alan.
Michael Glazer said:
> I have just done two runs on a Panalytical one with 0.04 soller slits and
> one with 0.02 (both with a CuKa1 premonochromator) both for about 9 hours.
> The strongest peak for the 0.02 case is 2700 counts, half width 0.08
> degrees and a background of 25 counts. The same peak with the 0.04 slits
> has 70000 counts, half width 0.11 degrees and a background of 700 counts.
______________________________________________
Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE
<[EMAIL PROTECTED]> +33.476.98.41.68
http://www.NeutronOptics.com/
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