Lachlan and others,
Another question about goniometer setup that has little to do with
Rietveld method but I thought I might tap the vast experiences of the
list participants:
We also have a Philips 1820 with ADS but I have a question for you on
another topic. We have been noticing a degradation in the acuracy of
the low angle peak positions (mostly by the inability of the S/M
software to match micas and chlorites that used to be reasonably well
id'd) lately that coincides with resetting the zero2T on the 1710 after
a PM visit. The Philips service rep claims the problem is the extra
weight of our Kevex PSi detector on the goni arm and possibly excessive
wear on the goni gears. Have you any experience with situations like
these (heavy weight detectors)?
The problem crops up after each PM visit when resetting of the zero2T
on the 1710 is required to get the peaks back in line (normally by
using SRM640b and / or Quartz) above about 24degrees (Co). I have a
feeling it has something to do with the service and possibly the
replacement of a gripping o-ring in the sample spinner mechanism
(different thicknesses causing displacement erros of varying mag
depending on the o-ring thickness? - just guessing).
The Philips rep is coming on Tuesday to do a PM visit and I am going to
get him to check this out but I am interested in opinions of others.
TIA
Stu
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/ \._ _|_ _.._ o _ Stu Miller - Mineralogist
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