> ---------- > From: Liste serveur[SMTP:[EMAIL PROTECTED]] > Sent: Wednesday, January 12, 2000 9:34 AM > To: [EMAIL PROTECTED] > Subject: Returned mail: Private list 'rietveld_l' > > Sorry, you are not a subscriber to the list, or your address has > changed. > So, you are not allowed to send mail to this list. > Please, resend your mail from the original subscription address. > > ------ Unsent message follows ------ > X-Listserv-To: rietveld_l > From [EMAIL PROTECTED] Wed Jan 12 16:34:16 2000 > Received: from out.esrf.fr (out.ill.fr [192.168.100.99]) > by onyx.ill.fr (8.8.6/8.8.6) with SMTP id QAA22366 > for <[EMAIL PROTECTED]>; Wed, 12 Jan 2000 16:34:15 +0100 (MET) > Received: (from uucp@localhost) by out.esrf.fr (8.6.10/8.6.10) id QAA22377 > for <[EMAIL PROTECTED]>; Wed, 12 Jan 2000 16:36:31 +0100 > Received: from texgate.amoco.com(204.149.20.10) by out.esrf.fr via smap > (V1.3) > id tmp022240; Wed Jan 12 16:36:07 2000 > Received: by interlock.amoco.com id JAA16183 > (InterLock SMTP Gateway 3.0 for [EMAIL PROTECTED]); > Wed, 12 Jan 2000 09:38:07 -0600 > Received: by interlock.amoco.com (Protected-side Proxy Mail Agent-2); > Wed, 12 Jan 2000 09:38:07 -0600 > Received: by interlock.amoco.com (Protected-side Proxy Mail Agent-1); > Wed, 12 Jan 2000 09:38:07 -0600 > Message-Id: <EC8979373E35D3118BE00008C7CFB440200970@AMNAPX1> > From: "Kaduk, Jim A" <[EMAIL PROTECTED]> > To: "'RIETVELD_L Distribution List'" <[EMAIL PROTECTED]> > Subject: RE: Accuracy and reproducibility of x-ray powder diffractometers > Date: Wed, 12 Jan 2000 10:37:05 -0500 > Mime-Version: 1.0 > X-Mailer: Internet Mail Service (5.5.2232.9) > Content-Type: text/plain > > We have several quality control procedures. > > Each week, we measure the 20-60 deg portion of a reference specimen of > NIST > 640b dispersed in epoxy on each instrument, to monitor changes in > intensity > and position of the peaks (mostly to watch tube intensity decay). > > From time to time, we measure full (20-140 deg) patterns of NIST 1976 > alumina plate, and use the patterns in Rietvedl refinements (GSAS) to > determine new instrument parameters. Most of our work involves Rietveld > refinement, so these parameters serve as good QC. > > We still do some "old fashioned" quantitative analyses, in which we > measure > the integrated areas of clusters of peaks (mostly for certain zeolite > catalysts). Each time we make such a measurement of a real sample, we > measure the pattern of a reference specimen. > > We find that the use of an internal standard (at a known concentration) > for > both profile intensities and peak positions reduces (not eliminates) most > of > the common errors associated with quantitative analysis using powder > diffraction techniques. > > Jim Kaduk > [EMAIL PROTECTED] > > > ---------- > > From: Alan Hewat[SMTP:[EMAIL PROTECTED]] > > Reply To: RIETVELD_L Distribution List > > Sent: Thursday, January 06, 2000 4:24 AM > > To: [EMAIL PROTECTED] > > Subject: Accuracy and reproducibility of x-ray powder diffractometers > > > > > > Question posted on behalf of Dr K.V.Rao <[EMAIL PROTECTED]> > > > > >Recently we procured one x-ray powder diffractometer from a reputed > > vendor. During installation we asked them to show us the accuracy and > > reproducibility of the system. Initially they said that the quartz > > standard > > they have supplied with the instrument is not a very good crystalline > > sample. So we have to procure a certified standard sample from some > place > > then they can demonstrate the accuracy and reproducibility on that > sample. > > When we told them that it is their responsibility to provide the proper > > standard and demonstrate the specifications asked by us and quoted by > > them, > > they started telling that it is not possible to check the accuracy and > > reproducibility at the site with the existing software available on the > > system. These can be checked only at the manufacturing factory where > they > > have to use special measuring tools and software. So now we are unable > to > > accept the system just based on their brochure/manual specifications. > > > > > >Please let me know the following. > > >1. What is the normal procedure followed to check the accuracy and > > reproducibility of the powder diffractometer? > > >2. Is it true that the accuracy and reproducibility can not be checked > at > > site and they can only be measured at the manufacturing factory? > > >3. Is it true that they need special tools and separate software apart > > from whatever they have supplied with the instrument for this purpose? > > > > > >Please send your comments / suggestions to the following address > > > > > >Attn: Dr. K.V.Rao > > >e-mail: [EMAIL PROTECTED] > > > > > >or [EMAIL PROTECTED] > > > > > >Thanking you in advance > > > > Alan Hewat, ILL Grenoble, FRANCE <[EMAIL PROTECTED]> tel (33) 4.76.20.72.13 > > ftp://ftp.ill.fr/pub/dif fax (33) 4.76.20.76.48 http://www.ill.fr/dif/ > > >
