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RE: [sdpd] Protection of samples
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<P><FONT SIZE=2>I also favour the solution provided by Dr. Leinenweber. We have designed our own sample holders. They consist of a regular powder sample holder onto which a half sphere can be mounted. In the half sphere, a slot is machined away and this is sealed with mylar foil (regular, not metallised) In that way, the X-rays always fall perpendicular to the windows and there is no diffraction. The absorption is really minimal. On the other hand, we will have to change the design somewhat, because the minimum measuring angle is too high (the windows don't come low enough). Eventually, we could go to a really air-tight design with beryllium windows. As we are working with hazardous materials, this could provide us with a local air-tight sample holder, which is much easier than putting the entire diffractometer in a glove box.</FONT></P>
<P><FONT SIZE=2>Kind regards,</FONT>
</P>
<P><FONT SIZE=2>Sven</FONT>
</P>
<P><FONT SIZE=2>> -----Original Message-----</FONT>
<BR><FONT SIZE=2>> From: Kurt Leinenweber [<A HREF="mailto:KURTL...@asu.edu";>mailto:KURTL...@asu.edu</A>]</FONT>
<BR><FONT SIZE=2>> Sent: Monday 18 June 2001 19:41</FONT>
<BR><FONT SIZE=2>> To: sdpd...@yahoogroups.com</FONT>
<BR><FONT SIZE=2>> Subject: RE: [sdpd] Protection of samples</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> Hi all,</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> I generally prefer to use a dry cell with the Kapton or mylar </FONT>
<BR><FONT SIZE=2>> away from the</FONT>
<BR><FONT SIZE=2>> sample, so it is not in diffracting position, and </FONT>
<BR><FONT SIZE=2>> perpendicular to the x-ray</FONT>
<BR><FONT SIZE=2>> beam so there is no absorption correction for the dry cell </FONT>
<BR><FONT SIZE=2>> cover when a</FONT>
<BR><FONT SIZE=2>> Rietveld refinement is performed (ie the cover is a </FONT>
<BR><FONT SIZE=2>> semicircle about 2-3 cm</FONT>
<BR><FONT SIZE=2>> above the sample). It requires some design but seems to be </FONT>
<BR><FONT SIZE=2>> worth it; since</FONT>
<BR><FONT SIZE=2>> I designed this one (for the Siemens D-5000) I have had </FONT>
<BR><FONT SIZE=2>> requests to have new</FONT>
<BR><FONT SIZE=2>> ones made for 8 different research groups at our University!</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> - Kurt Leinenweber</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> -----Original Message-----</FONT>
<BR><FONT SIZE=2>> From: Greg Beis [<A HREF="mailto:bgreg...@iesl.forth.gr";>mailto:bgreg...@iesl.forth.gr</A>]</FONT>
<BR><FONT SIZE=2>> Sent: Monday, June 18, 2001 9:59 AM</FONT>
<BR><FONT SIZE=2>> To: sdpd...@yahoogroups.com</FONT>
<BR><FONT SIZE=2>> Subject: [sdpd] Protection of samples</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> Dear all,</FONT>
<BR><FONT SIZE=2>> I have a question concerning ways of protecting air sensitive samples.</FONT>
<BR><FONT SIZE=2>> I am doing powder diffraction on some extremely air sensitive </FONT>
<BR><FONT SIZE=2>> compounds. For</FONT>
<BR><FONT SIZE=2>> that reason, I use aluminized mylar in order to seal them on </FONT>
<BR><FONT SIZE=2>> the holder.</FONT>
<BR><FONT SIZE=2>> Unfortunately, the mylar gives a very broad peak at around 20-30 deg.</FONT>
<BR><FONT SIZE=2>> 2theta, in an area where I expect many small reflections of </FONT>
<BR><FONT SIZE=2>> my samples which</FONT>
<BR><FONT SIZE=2>> I cannot distinguish them.</FONT>
<BR><FONT SIZE=2>> Does anyone of you know any other "protective" material, </FONT>
<BR><FONT SIZE=2>> except mylar, for</FONT>
<BR><FONT SIZE=2>> that purpose? Any suggestions are more than wellcome.</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> Thank you in advance,</FONT>
<BR><FONT SIZE=2>> Gregory</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> </FONT>
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