Re: Siemens Goebel Mirrors

Stanislaw Gierlotka ( xray@iris.unipress.waw.pl )
Mon, 29 Jul 1996 21:54:13 -6000

Forget it!
The only 'powder' case it can be used for is when the sample's
surface is not flat and you are not allowed to either pulverize it
or polish it's surface. This case is covered in the Siemens' Lab
Report which you can obtain from them.
We investigated the mirror's potential uses extensively and even
gave it a try at their headquarters in Karlsruhe. The concusions are:
1. It has been over-advertised
2. It is virtally useless for powder diffraction
3. In the high resolution work (single crystals and epitaxial layers) the
intensity gain over conventional setup is 4 times at most
4. It can be usefull sometimes but in !!!VERY SPECIAL!!! cases

If you try to use it for every-day powder data collection you not only waste
your money but the time also - if you go for the same statistics and
resolution the Bragg-Brentano geometry can give you.
BTW how expensive it is in US - in Europe they sell it for roughly $2700?
If you need more details let me know.
The general advice is to buy something else for the money. It can be PSD
which will give you 50 times faster data collection at the expense of the
resolution(some 50% worse), or some spare X-ray tubes so that you can run
them at full power (intensity gain at the expense of the tube life-time).
And for goodness sake, don't believe the Siemens salesmen. Even people
in their demonstration lab hardly know what they are dealing with.
Stan
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Stan(islaw) Gierlotka | High Pressure Research Centre
xray@iris.unipress.waw.pl | Polish Academy of Sciences
X-Ray Diffraction Lab. | Sokolowska 29, 01-142 Warszawa, Poland
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