Karin,
I assume you have no monochromator as you are using a Ni filter. I hope this isn’t a very dumb question, since I am not familiar with equipment from this manufacturer, but don’t you have the receiving slit and anti scatter slit the wrong way round? The anti scatter slit should be between the receiving slit and the detector. The receiving slit is the small one at the radius of the focusing circle. So the slits should be 1mm/.1mm/1mm. not 1mm/1mm/.1mm or were they not written down in any particular order. That would explain low countrates leading to long counting time to get decent counting statistics.
Mike Handley
Mike Handley Analytical Services
17143 S Ivy Cir
Houston TX 77084
Tel: 281 856 8893
Fax: 281 286 8393
web: www.myxrf.com
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-----Original Message-----
From: Support and use of X-ray diffraction instrumentation [mailto:[log in to unmask]] On Behalf Of Karin Liltorp
Sent: Wednesday, May 23, 2012 2:08 AM
To: [log in to unmask]
Subject: Re: NIST standard 1976 does not match certified intensities
Hello again,
Thanks for all of you useful advise. We have now increased sampling time (we use locked coupled/step scan/1mm/1mm/0.1mm/Ni) The corundum standard is A13-B73 (-S) F-Nr 06/10-504
A 1 hour run in the region 24 to 38 (same sample position for all runs) and using the peak search option - leads to following results:
Run no. corundum 1 time fra 24-38
Angle d value Intensity Intensity %
2-Theta ° Angstrom Count %
1 25,586 347,874 6715 34.30
35,172 254,948 19594 100.00
2 25,585 347,890 6928 34.50
35,170 254,962 20067 100.00
3 25,589 347,835 6871 35.00
35,173 254,946 19636 100.00
4 25,595 347,756 6350 32.20
35,177 254,916 19714 100.00
5 25,594 347,765 6497 33.50
35,179 254,900 19386 100.00
6 25,596 347,749 6584 33.40
35,180 254,895 19725 100.00
Using the "area" option (manual definition of baseline) leads to following results
Obs. Max Max Int. Net HeightFWHM Net Area %
2-Theta ° Cps Cps 2-Theta ° Cps x 2-Theta °
25,587 1343 1299 0.066 131.5 32.85
35,158 3925 3892 0.06 400.3
25,586 1378 1335 0.063 131.2 32.48
35,158 4020 3988 0.059 403.9
25,588 1376 1333 0.062 131.9 33.10
35,158 3933 3898 0.06 398.5
25,589 1287 1244 0.068 130.2 32.43
35,160 3947 3917 0.06 401.5
25,589 1315 1273 0.064 131.1 32.54
35,161 3882 3852 0.061 402.9
25,589 1335 1289 0.062 130.3 32.20
35,161 3950 3919 0.06 404.7
The variation looks much better and is hopefully within limits (haven't found the certificate for this "old" standard")
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