Andrew,
my first suggestion is to approach Panalytical for the service note for the device. You are going to need it in order to do the proper adjustment.
The 'automatic' divergence slit is the last or next to last device to be adjusted, the alignment of the diffractometer needs to be checked/verified prior to its adjustment. Presumably it can be used in fixed slit mode (or disabled and adjusted manually to a fixed setting). You need a fixed slit to test the alignment.
The sympton you describe - we are not getting the so-called 'virutally equal area' of irradiation (which we can evaluate on a fluorescent screen) - says there is something wrong, but it may be a theta zero error (as you suspect) - this is a diffractometer alignment fault that needs to be checked/corrected before other things.
regards and good luck,
Tony Raftery
________________________________________
From: Support and use of X-ray diffraction instrumentation [[log in to unmask]] On Behalf Of Andy McDonald [[log in to unmask]]
Sent: Wednesday, 18 March 2009 5:22 AM
To: [log in to unmask]
Subject: Re: Automated Divergence Slit
All:
First off, I would like to thank all of you who, in a rapid and timely manner, responded to my previous email regarding the XDS2000; its great to know there are so many out there that actually care! Karl Hofmann is to be personally thanked in this regard.
Secondly, and not to look a gift horse in the mouth, but we're having some additional issues with another diffractometer, specifically, the PW 1386/55 automatic divergence slit. We never received any documentation with the diffractometer to which it is attached, so know absolutely nothing about, for e.g., proper alignment. Right now, its on a PW 1820 theta-theta system but we're having issues: we are not getting the so-called 'virutally equal area' of irradiation (which we can evaluate on a fluorescent screen). On top of this, our near 47 degree peak for Si is not looking pretty at all (no clear peak separation, for e.g.). When we operate the system in theta-two theta mode, the peak (and associated counts) are fine and dandy, so we suspect we may not have got everything in proper alignment for the theta-theta setup. If you might have any feedback on the use/proper alignment of the auto divergence slit, we'd really appreciate hearing from you (I'm quickly finding that re-inventing the wheel is not most efficient use of one's time).
Thanks in advance. Andy McDonald
Dr. Andrew M. McDonald
Chair, Department of Earth Sciences
Professor, Mineralogy & Crystallography
Academic Advisor, Central Analytical Facility, Solid Phase Section
Associate Editor, Canadian Mineralogist
Department of Earth Sciences
Laurentian University
935 Ramsey Lake Road
Sudbury, ON
Canada
P3E 2C6
Ph: 705-675-1151 ext. 2266
Fax: 705-675-4898
Email: [log in to unmask]
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