Anomalous scattering factor and Dispersion coefficients
Dear Rietvelders, I am little confused about the term "Anomalous scattering factor" and "Dispersion coefficients". "Anomalous scattering factor" can be found here http://skuld.bmsc.washington.edu/scatter/AS_form.html "Dispersion coefficients" can be found here http://www.cxro.lbl.gov/optical_constants/asf.html Their numbers are quite different: e.g. Fe @ CrKα: f0=18.474, Δf'=-1.6 Δf"=0.9 ;however, the corresponding dispersion coefficients are f' ~24.6808 and f" ~0.759346 Can anyone explain their relationship? Thanks! -- Yours Sincerely, Dr. Xiaodong(Tony) Wang XRD Application Scientist Bruker Singapore Pte. Ltd.++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re: Re: Anomalous scattering factor and Dispersion coefficients
Thanks Jon, Luca and Jeremy, Much appreciate for your info and comments! Yours, Tony:) Sent from Mail Master On 06/12/2015 00:25, Luca Lutterotti wrote: John is correct, be careful that you are trying to compare same quantities but in a completely different units and definitions. I discover by myself that you cannot mix scattering factors, absorption factors, photo absorption etc. coming some from the diffraction community and some from the spectroscopic community. So Henke is used by the spectroscopic community (second link) and need proper conversion to be applied for scattering….. I actually use Henke derived work in Maud now as I can compute the dispersion coefficients (and absorption) for every wavelength not only the tabulated ones usually adopted in diffraction, but I had to convert everything to be consistent (absorption etc.). Best regards, Luca On Jun 11, 2015, at 6:07 PM, Jonathan WRIGHT wrote: Dear Xiaodong, Jeremy, Isn't it equation 3 here? http://www.nist.gov/srd/upload/jpcrd488.pdf f1/f2 are "dispersion" numbers and f'/f" are the "anomalous" ones. The relativisitic correction number for iron then shows up on page 221. Best, Jon === On 11/06/2015 17:27, Jeremy Karl Cockcroft wrote: Hi Xiaodong, I think that the numbers quoted for f' in the second case have had 26e (atomic no.) added to them, i.e. it refers to the total dispersion value for the real component (as opposed to the imaginary component). Given that the numbers quoted are close to an absorption edge, then the remaining differences are not unexpected depending on source and precise energy quoted. If graphs of the data are plotted with Z subtracted, then they look very similar apart from the precise value of the minimum of f' at the absorption edge itself. Just my thoughts on it... Jeremy Karl. *** Dr Jeremy Karl Cockcroft Department of Chemistry (University College London) Christopher Ingold Laboratories 20 Gordon Street London WC1H 0AJ United Kingdom +44 (0) 20 7679 1004 (laboratory) j.k.cockcr...@ucl.ac.uk or jeremyk...@gmail.com http://img.chem.ucl.ac.uk/www/cockcroft/homepage.htm *** On 11 June 2015 at 15:33, iangie wrote: Dear Rietvelders, I am little confused about the term "Anomalous scattering factor" and "Dispersion coefficients". "Anomalous scattering factor" can be found here http://skuld.bmsc.washington.edu/scatter/AS_form.html "Dispersion coefficients" can be found here http://www.cxro.lbl.gov/optical_constants/asf.html Their numbers are quite different: e.g. Fe @ CrKα: f0=18.474, Δf'=-1.6 Δf"=0.9 ;however, the corresponding dispersion coefficients are f' ~24.6808 and f" ~0.759346 Can anyone explain their relationship? Thanks! -- Yours Sincerely, Dr. Xiaodong(Tony) Wang XRD Application Scientist Bruker Singapore Pte. Ltd. ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++ ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++ ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re:Re: Peak assymtery not able to fit
Hi Apu, Your peak looks super-Lorentzian. Super-Lorentzian peak can be due to bimodal distribution (Young, R. A. & Sakthivel, A. (1988). J. Appl. Crystallogr.21, 416-425.) or wide Lognormal distribution (Popa, N. C. & Balzar, D. (2002). J. Appl. Crystallogr.35, 338–346.). In the latter case, Popa et al. directly refine mean and standard deviation of crystallite size distribution to the profile. His model has been put into TOPAS (Wang, X., Li, J., McDonald, R. G., Van Riessen, A. & Hart, R. D. (2015). J. Appl. Crystallogr.48, 814–826.) Cheers! P.S. No one is allow to send attachments to Rietveld_I list. You need to paste their links instead. -- Yours Sincerely, Dr. Xiaodong(Tony) Wang XRD Application Scientist Bruker Singapore Pte. Ltd. At 2015-06-15 14:29:28, "Patrick Weisbecker" wrote: Apu, I would try bimodal distribution of crystallite sizes: in fullprof you can use two phases with the same structure and different peak shape and broadening. Regards, Patrick Patrick Weisbecker Laboratoire des Composites ThermoStructuraux (LCTS) 3 allée de la Boétie 33600 PESSAC-France De : Apu Sarkar À : "rietveld_l@ill.fr" Envoyé le : Lundi 15 juin 2015 7h59 Objet : Peak assymtery not able to fit Hi, I am working on a nanocrystalline Nickel sample. I am not able to fit the peaks to get FWHM and Integral Breadth. Please see the attached images. Fig. 1 shows the profile and a zoomed view of a peak. Tail part of the peak is broader. Fig. 2 shows the winplotr fit. It is not matching the max intensity. Please give you suggestions to get a better fit for this kind of XRD peak. Thanks Apu ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++ ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re:Capillary data with odd shaped peaks
Dear Alan, I have a few patterns of samples in 0.3mm Boron-Rich Glass capillaries but collected in Debye-Scherrer mode. What does "Capillary Specimen data collected in reflection mode" mean, high angle peaks only? Cheers! -- Yours Sincerely, Dr. Xiaodong(Tony) Wang XRD Application Scientist Bruker Singapore Pte. Ltd. At 2015-06-15 00:32:03, "Alan Coelho" wrote: Hi all I'm looking for Capillary Specimen data collected in reflection mode which shows odd bumps on the peaks. I'm aware that there are supposed to be odd shaped peaks but I am looking for example data that show it. If anyone has such data and are willing to part with it then let me know. cheers alan++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re:Re: Air scatter blocker
Dear Friends,
Below macro was already developed in 10th TOPAS user meeting @ Adelaide:
TOPAS syntax code for the modified intensity correction and flat specimen
asymmetry peak shape convolution
‘Variable_Divergence_Shape_Correction: v = footprint (EDFL); keh = knife edge
height
macro Variable_Divergence_Shape_with_knife_edge(v, keh)
{one_on_x_conv = If(Th < 2*ArcTan(2keh/v), -v^2 Sin(2 Th) Rad/(4 Rs^2), -2
keh^2 (Cos(Th))^3/Sin(Th) Rad/Rs^2);}
‘Variable_Divergence_Intensity_Correction: v = footprint (EDFL); keh = knife
edge height
macro Variable_Divergence_Intensity_with_knife_edge(v, keh)
{scale_pks = If(Th < 2*ArcTan(2keh/v), Sin(Th), 2 keh/v Cos(Th));}
If you use fix divergence slit:
‘Fix_Divergence_Shape_Correction: divang = divergence angle (EDFA); keh = knife
edge height
macro Fix_Divergence_Shape_with_knife_edge(v, keh)
{prm v = R divang Deg /Sin(Th);
one_on_x_conv = If( Rs Sin(divang/2 Deg) / Sin(Th - divang/2 Deg) Tan( (Th -
divang/2 Deg) > keh, -(Pi/360)/Tan(Th) divang^2, -2 keh^2 (Cos(Th))^3/Sin(Th)
Rad/Rs^2);}
‘Fix_Divergence_Intensity_Correction: v = footprint; keh = knife edge height
macro Fix_Divergence_Intensity_with_knife_edge(v, keh)
{scale_pks = If(Rs Sin(divang/2 Deg) / Sin(Th - divang/2 Deg) Tan( (Th -
divang/2 Deg) > keh, 1, 2 keh/v Cos(Th));}
or something similar...
Cheers!
--
Yours Sincerely,
Dr. Xiaodong(Tony) Wang
XRD Application Scientist
Bruker Singapore Pte. Ltd.
At 2015-07-30 21:29:40, "Matthew Rowles" wrote:
Hi Robert
Exactly! If installed properly, it doesn't affect anything except the
background. I had a nice spreadsheet setup to give me knife heights vs
divergence vs maximum 2T value to make sure that I don't run into forbidden
teritory.
I dispute your assertion that a knife wouldn't be necessary if the optics
worked properly. As far as I know, the only way to get rid of air scatter would
be to evacuate the beam path.
I'm currently doing some experiments with an old knife setup on a D8, and I'm
getting some funny bumps at low angle, but in my experience with a newer know
setup, that is due to a divergence that is too big. I'll see if I can put
something together.
Matthew
On 30 Jul 2015 2:04 pm, "Dr. Robert Möckel" wrote:
Hi Matthew,
what you mentioned earlier is not completely correct:
An anti-air scatter (or beam knife) does not only reduce background (mainly at
low angles), but also cuts intensity at higher 2theta values, if not installed
correctly. It does not result in a sample displacement error, it just cuts
intensity as it cuts off the beam like you mentioned.
This is also an relatively easy issue to modell, I even managed to put it into
an excel-file to calculate the max. 2theta angle that can be measured at a
certain knife height and detector length. BGMN "handles" this properly as well.
Nowadays, there are even knifes available that move vertically, depending on
the actual 2theta value.
In general, a beam knife would not be necessary if the optics worked properly,
i.e. the optical path is not disturbed or diffracted or fluorescence would not
be generated somewhere in the beam path. Basing on our experience, the main
source of these unwanted X-rays are within or close to the tube itself, making
it hard to suppress it effectively.
All these things result in some strange background phenomena at low angles
(bumps/edges...). We discussed these issues with Reinhard Kleeberg and others
for a while. It seems to be a serious problem in modern devices, as we
experienced this on our own PANalytical and other (Bruker) devices from
colleagues.
Regards,
Robert
, 30 Jul 2015 11:53:15 +0800 schrieb Matthew Rowles :
Hi Jilin
You could probably add a note to your input file.
Not everything you use in your hardware can be either properly modelled, or
influence the pattern significantly. Do you need to model the anti-scatter
slits? They help reduce background.
One thing that could happen is that if the knife is set up incorrectly, it
will cut off the beam, shifting the centroid of diffraction. That may mimic
a sample displacement type error.
Re your comment about double-digit results. Are you talking about the quant
results given in the GUI? The actual answer is going to be a lot less
precise than that.
Matthew
On 30 July 2015 at 09:19, ji zhang wrote:
Matthew
I was thinking shouldn't we be able to input some parameters to reflect
this hardware configuration in the program?
I forgot that I had asked the same question in2007 in this list. Nobody
seemed to care enough except Dr Bergmann. Then I went to do log analysis,
and this thing is completely forgotten.
Currently we have topaz where I can't find a way to circumvent this yet or
to handle this as I called it. I am thinking we may need a copy of bgmn.
Certainly both give double digit results (albeit not the same) and both
look accurate.
Sent from Yahoo Mail for iPhone
On Jul 29, 2015, 5:56:41 P
Re: RE: Aking for Advice - reduce the current to X-ray tube to avoid director saturation at low angels
Echo reducing tube power just reducing intensity which reduces your peak height together with the background level. It won't help on the peak to background ratio. What you need to improve is the beam path. WhenI was checking the low angle beam path, I measured the stage/goniometer dimensions and draw the beam path in AutoCAD. And I can calculate the footprint length of illuminated sample FP=Rα/Sinθ, where R=goniometer radius; α=divergence slit angle in rad; θ is half 2theta. With this equation I can calculate what divergence slit width should I use at what θ angle to make sure the beam is not exceed the sample area. If you have a motorised divergence slit, it is highly recommended to use the variable divergence slit mode which gradually opens the beam divergence (theta-compensating) and guarantees that the FP on sample is constant. With this mode, you won't have directe beam on detector. As Julian mentioned, a knife edge hovering above sample could largely reduce air scattering. Anti-scattering slit is not that useful at low angle for PSD. Cheers, Tony 发自 网易邮箱大师 On 03/06/2016 19:46, Julian Richard Tolchard wrote: Shay, Can we assume you are working with a reflection mode instrument? You have two primary sources of background - the primary beam hitting the detector directly, and x-rays scattering from the air rather than the sample. The first of these you control with the divergence slits, but really shouldn't be a problem until you go below 4-5 degrees. If you do scan from those sorts of angles, set the divergence slits to ~0.1 degrees to keep the beam on the sample. I haven't tested it myself, but you could also try reducing the detection window on the LynxEye if you want to go to really low angles (<2 degrees). The air scatter can be reduced with a special screen/knife that you should have received with the instrument, and correctly aligned it will reduce a lot of the background increase you see below 10-15 degrees 2-theta. There should be some instructions in the instrument manual about this. Using a smaller divergence slit (and a receiving slit if you have the option) will also reduce the background from airscatter. I don't think that lowering the tube power will help very much, jools From:rietveld_l-requ...@ill.fr [rietveld_l-requ...@ill.fr] on behalf of Shay Tirosh [stiro...@gmail.com] Sent: 06 March 2016 10:51 To:rietveld_l@ill.fr Subject: Aking for Advice - reduce the current to X-ray tube to avoid director saturation at low angels Dear Rietvelders I would like to avoid director saturation (we have a LYNXEYE detector) when I work at low angles (lower then 10deg). I thought it would be good to lower the current tube to reduce the current. say to 35mA instead of 40mA. Can you please comment on problems it should encounter? Can I correct problems by slowing down my scanning time? Thank you from advance Shay -- _ Dr. Shay Tirosh Institute for Nanotechnology & Advanced Materials Bar Ilan University Ramat Gan, 52900 Israel Phone: +972-(0)30-531-7320 Mobile: +972-(0)54-8834533 Email: stiro...@gmail.com _ ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re:Data collection strategy from low angles - Bruker D8 Advance, Lynx Eye XE detector
Dear Frantisek, >I have tried the 0.26 and 0.14° FDS, however a large "beam overflow" has >occurred. Moreover, the intensities of diffractions at higher angles are very >low in comparison to the data collected with ADS slits. [TW] At θ=1° , 0.26 and 0.14° FDS coresponding to ~39 and ~74 mm footprint on sample, respectively, which is much longer than your sample length 15mm. This beam overspill will induce air scattering which increases background at that angle. Using ADS, the sample volume illuminated is increasing with Sinθ dependance, therefore you observe "higher" peak intensity at high angle. At 2θ=2°, the knife edge hieght should be lower; At 2θ=50°, the knife edge height should be higher. Therefore, I recommanded you use Bruker's Motorised Knife Edge, which retracts itself in real time accoding to beam divergence and # of detector openning channels at each θ. Your LynxEye XE PSD should be able to opearte in Variable Detector Openning mode, which opens fewer channels at low angle and all channels at higher angle. You may want to try the scan type: "Coupled 2Theta/Theta (VDO)". However, the ultimate solution would be combining ADS, MKE, VDO together, which gives lowest possible background at low angle, ideal for recording clay basal reflections. -- Yours Sincerely, Dr. Tony Wang At 2016-10-21 21:59:23, "František Laufek" wrote: Dear all, I would like to ask you about your experience in collecting the XRD data from low angles (for me from 2° of 2Theta) to 50° 2Theta using the Bruker D8 Advance diffractometer (Bragg-Brentano geometry) with the Lynx Eye XE position sensitive detector. The studied samples are clay minerals and the main purpose of the task is qualitative and later (semi)quantitative phase analysis. I have fixed beam knife (=Anti-Scatter Screen) and ADS/FDS slits, 280 mm is the goniometer radius. The length of my samples is around 15 mm. After a few experiments and calculation, the optimal data collection strategy seems to be: - 10 mm automatic divergence slits (ADS), beam knife 2.5 mm above the sample (beam knife at this position does not interfere with the primary beam (to 50°) and still reduces the background at low angles). I have tried the 0.26 and 0.14° FDS, however a large "beam overflow" has occurred. Moreover, the intensities of diffractions at higher angles are very low in comparison to the data collected with ADS slits. Any suggestions are welcome. Frantisek Laufek Czech Geological Survey Prague Czech Republic ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re:Topas reporting macro
Hi Jools, 1) Press the icon "Show single peak curves" to have all the calculated peak profile displayed. 2) Right click the range "*.raw", and choose "save if displayed Yobs, Ycalc, Diff, Phases, Bkg" from the right-click menu. -- Yours Sincerely, Dr. Tony Wang At 2016-12-12 05:55:09, "Julian Richard Tolchard" wrote: >Hi all, > >A quick question - does anyone know an easy way to export the individual fits >for xo_Is type peaks in Topas? I just want a 2 column file for each peak (or a >collated file of all) that i can plot. > >I can't find anything in the documentation and my usual info repository (John >Evans' Topas wiki) seems to be offline. > >Thanks, > > >jools ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re:Bias - Intensity correction Nist 1976b
Hi Nelson, The X-ray atomic form factor has a propotion which changes with wavelegnth. So do not apply the relative intensities in Cu radiation in the NIST Certificate on your mearement in Co radiation. Even you simulate a corundum pattern from a Rietveld code under Co radiation, it will be different to your actural measurement, becasue the NIST 1976b has obvious preferred orientation. Maybe you can parameterise the preferred orientation levels from Cu data, by using a very aggressive model, like spherical harmonics, to achieve best fitting, then simulate a Co pattern after fixing the preferred orientation model. But even though, I think it will be less accurate than just measure it on a well aligned Co machine, which usually has been done in vendor's factories. Cheers! -- Yours Sincerely, Dr. Xiaodong(Tony) Wang At 2017-08-21 00:29:26, "Nelson Duarte" wrote: >Dear Rietvelders >Iam starting to use NIST standard reference material 1976b for >calibration of line position and intensity as a function of 2theta. >The intensity values of certificate are obtained in a cupper radiation. >I use cobalt radiation. I correct the polarization effect . > >It is necessary apply any additional bias (effect of radiation) to >correct intensity values ? > >Thank you from advance >Nelson > > ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re:Re: Powdll v2.60
Dear David, Why not upgrade your EVA, if you are talking about DIFFRAC.EVA. If I am still correct, you should be able to open the latest version of DIFFRAC.EVA using lower level license. You will not see the new functions specfic to higher level license, but will benefit from bug fixes since then, if any. Cheers! Tony Wang At 2018-11-02 17:28:54, "DAVID MARTINEZ BLANCO" wrote: Thanks Alan, But the issue is that latest version is incompatible with my EVA program v.2.0 (64 bits) so we need older versions. Regards, David De:rietveld_l-requ...@ill.fr en nombre de Alan Hewat Enviado: viernes, 2 de noviembre de 2018 10:15 Para: DAVID MARTINEZ BLANCO Cc:rietveld_l@ill.fr Asunto: Re: Powdll v2.60 Google finds the latest version of Powdll is 2.76, which you can download from http://users.uoi.gr/nkourkou/powdll/ | PowDLL - Πανεπιστήμιο Ιωαννίνων users.uoi.gr PowDLL is a .NET dynamic link library used for the interconversion procedure between variable formats of Powder X-Ray files. The DLL is capable of handling the most common file formats (binary and ASCII). The library can be used as a reusable component with any .NET language or as a standalone utility. | Otherwise I am not familiar with this application. Alan. On Fri, 2 Nov 2018 at 10:04, DAVID MARTINEZ BLANCO wrote: Dear Colleagues, I need urgently the versión 2.60 of the program Powdll for converted xrd files. I tried to download from oficial webpage but its link is disabled. Thanks in advance and best wishes. David Dr. David Martínez Blanco Técnico de Difracción de Rayos X Servicios Científico-Técnicos Universidad de Oviedo ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++ -- __ Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE +33.476.98.41.68 http://www.NeutronOptics.com/hewat __++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re:conversion of radiation
Hi Nelson, The very fact you see these two options means the software you are using does not provide deserved separated treatments for converting Ka1 and Ka2 lines. It is, most likely, simply applying Bragg's law to convert the 2theta axis only, which assumes Ka2 lines are from separate d-spacings hence positions them wrongly on the target wavelength. The correct way of using such kind of software is: FIRST strip Ka2, THEN "convert CuKa1 to CoKa1", otherwise: a) If you just apply "convert CuKa1 to CoKa1" without strip Ka2 first, the Ka1 lines positions will be converted correctly, but all Ka2 lines will be put at wrong positions. b) If you simply choose "convert CuKa average to CoKa average" without strip Ka2 first, then neither Ka1 lines nor Ka2 lines will be at correct position, but their "average position" will be right. Cheers! Cheers! Tony@QUT At 2019-01-08 04:04:10, "Nelsonsd" wrote: Dear colleagues I have a small question about conversion of copper to cobalt radiation. I have characteristic peaks of a Pharmaceutic API (literature) in copper radiation and I need to convert in cobalt radiation, can I use in ka1 of copper (1.54056 A) and Ka1 of cobalt or the best way is use Ka (ave) (1.54184 A) of copper and cobalt ? Thanks in advance Best regard++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Openning of X-ray Analysis Coordinator in QUT
Dear Rietvelders, Queensland University of Technology is seeking candidates for its recent openings of X-ray Analysis Coordinator position. The successful candidate needs to work with experienced XRD/XRF analysis team and internal/external customers. Please view details on https://qut.nga.net.au/cp/index.cfm?event=jobs.checkJobDetailsNewApplication&returnToEvent=jobs.processJobSearch&jobid=97834E20-5885-4E93-5916-ACFCA71EBDFE&CurATC=EXT&CurBID=1877E01E%2D78DD%2D4ED2%2D9D7A%2D9DB40135CFF4&jobsListKey=0b63db35%2D2604%2D4f68%2D93c4%2De29614d57ef9&persistVariables=CurATC,CurBID,jobsListKey,JobID&lid=22173930068 Cheers! -- Dr. Xiaodong (Tony) Wang Research Infrastructure Specialist (XRD) Central Analytical Research Facility (CARF) | Institute for Future Environments Queensland University of Technology++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Software re-binned PD data
Dear Rietvelder, I hope you are doing well. It is generally acknolwdged that Rietveld refinement should be performed on raw data, without any data processing. One of our diffractometer/PSD scans data at its minimal step size (users can see that the step size during scan is much smaller than what was set), and upon finishing, the measurement software re-bin the counts to the step size what users set (so the data also looks smoother, after re-bin). My I ask is this re-bined data from the measurement software considered as "raw data" or "treated data"? And can we apply Rietveld refinement on this data? Any comments are welcome. :) -- Dr. Xiaodong (Tony) Wang Research Infrastructure Specialist (XRD) Central Analytical Research Facility (CARF) | Institute for Future Environments Queensland University of Technology++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re:RE: Software re-binned PD data
Dear Rietvelders, Thanks for your opinions! The "re-binning" of 1D data was done by my measurement software automatically, rather than by analysis software. The CPS is unchanged after its "re-binning". This means, rather than adding counts of neighboring steps, it is *averaging* my data (sum counts up then divided by the number of combined bins)! I have a feeling what my measurement software doing is not correct... -- Dr. Xiaodong (Tony) Wang Research Infrastructure Specialist (XRD) Central Analytical Research Facility (CARF) | Institute for Future Environments Queensland University of Technology 在 2019-09-27 10:31:45，alancoe...@bigpond.com 写道： Hi Tony >My I ask is this re-bined data from the measurement software considered as >"raw data" or "treated data"? I’m not sure what is meant by treated data. Almost all neutron data and synchrotron data with area detectors are “treated data”. If the detector has a slit width in the equatorial plane that is 0.03 degrees 2Th then it makes little sense using a step size that is less than 0.03/2 degrees 2Th. If rebinning is done correctly (see rebin_with_dx_of in the Technical Reference) then rebinning is basically collecting redoing the experiment with a wider slit. In the case of your PSD then the resolution of the PSD would be the smallest slit width. If the data has broad features relative to the slit width then rebinning (or using a bigger slit width) should not change the results. You could simulate all this using TOPAS to see the difference. Correct rebinning should not affect parameter errors. This is a question that is not simple to answer and if there’s concern then: Simulating data with the small step size and performing a fit And then rebinning with various slit widths and then fitting And then comparing parameters errors and parameter values for all the refinements should shine light on the area. I don’t know where but I feeling is that there should be papers on this. Cheers Alan From: rietveld_l-requ...@ill.fr On Behalf Of iangie Sent: Thursday, September 26, 2019 1:40 PM To: rietveld_l@ill.fr Subject: Software re-binned PD data Dear Rietvelder, I hope you are doing well. It is generally acknolwdged that Rietveld refinement should be performed on raw data, without any data processing. One of our diffractometer/PSD scans data at its minimal step size (users can see that the step size during scan is much smaller than what was set), and upon finishing, the measurement software re-bin the counts to the step size what users set (so the data also looks smoother, after re-bin). My I ask is this re-bined data from the measurement software considered as "raw data" or "treated data"? And can we apply Rietveld refinement on this data? Any comments are welcome. :) -- Dr. Xiaodong (Tony) Wang Research Infrastructure Specialist (XRD) Central Analytical Research Facility (CARF) | Institute for Future Environments Queensland University of Technology++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re:Re: Software re-binned PD data
Dear Rietvelders, Thanks for your opinions! I guess keeping an eye on measurement software's rebinning behavior (especially if it's done without informing user)is still necessary, becasue too much rebinning might deform the peak profile especially in the overlapping regions. Plus errors from Rietveld refinement are sometime used to judge the suitability of the refinement model, etc... Matthew's suggsetion of testing counting statistics experimentally is quite good. I am thinking of just check the flat background region which is already repeat measurements of a count level by the target system. Therefore, placing the "n-cursor" in Profex (a "+-sqrt(Y)" cursor varing with mouse Y position) to the data's background is quite handy to visually check if the data drifted too much from the Possion distribution. In my software, I tested the noise levels of several flat background regions of my data like below, they are always smaller than sqrt(Y). Looks like Alan is correct: the data was saved for user(me) with a better look xdd C:\***.raw start_X 66 finish_X 67 prm bkga 0.69281` prm bkgb 96.32814` fit_obj = bkga X + bkgb; xdd_sum num_data = 1;:101 xdd_sum sum_sqr_diff = (Yobs-Ycalc)^2;:7247.6514 prm Standard_Deviation_Obs = Sqrt(sum_sqr_diff/num_data);:8.47106 prm PossionTest = Standard_Deviation_Obs/Sqrt(bkga (Get(start_X)+Get(finish_X))/2 + bkgb);:0.70988` Thank you very much for your help! -- Dr. Xiaodong (Tony) Wang Research Infrastructure Specialist (XRD) Central Analytical Research Facility (CARF) | Institute for Future Environments Queensland University of Technology Address: XRD lab, P Block, Gardens Point campus, 2 George St Brisbane QLD 4000 At 2019-09-27 17:54:18, "Reinhard Kleeberg" wrote: The problem of falsified counting statistics (deviating from Poisson distribution) sometimes arises even from (wrong) conversion of 0D detector data (typically when originally cps have been stored and the counting time got lost in the conversion), and is quite common when 1D detector data are exported to 3rd party formats and the number of active channels is not considered correctly in the export routine. As a tool for a quick coarse check of the correct noise (like Matthew has suggested below), Nicola Doebelin has integrated a "noise" cursor in his PROFEX software https://profex.doebelin.org/ simply showing the +-sqrt(n) bars. If the noise of a pattern significantly deviates from this interval, something was going wrong, either in instrumental data collection/pretreatment or during export or conversion. No big science, but very helpful to identify bad or manipulated data. Reinhard Am 27/09/2019 um 08:15 schrieb Matthew Rowles: Hi Tony If you want to have a look at what the uncertainties are doing, then try scanning over a peak a couple of dozen times (maybe with a few different mA settings on the tube, maybe with some different step times) to collect a range of different intensities. The standard deviation of the "raw" counts (not raw CPS) should approximately the square root of the number of counts. If it is different, then something squirrelly is going on. Matthew On Fri, 27 Sep 2019 at 13:46, iangie wrote: Dear Rietvelders, Thanks for your opinions! The "re-binning" of 1D data was done by my measurement software automatically, rather than by analysis software. The CPS is unchanged after its "re-binning". This means, rather than adding counts of neighboring steps, it is *averaging* my data (sum counts up then divided by the number of combined bins)! I have a feeling what my measurement software doing is not correct... -- Dr. Xiaodong (Tony) Wang Research Infrastructure Specialist (XRD) Central Analytical Research Facility (CARF) | Institute for Future Environments Queensland University of Technology 在 2019-09-27 10:31:45，alancoe...@bigpond.com 写道： Hi Tony >My I ask is this re-bined data from the measurement software considered as >"raw data" or "treated data"? I’m not sure what is meant by treated data. Almost all neutron data and synchrotron data with area detectors are “treated data”. If the detector has a slit width in the equatorial plane that is 0.03 degrees 2Th then it makes little sense using a step size that is less than 0.03/2 degrees 2Th. If rebinning is done correctly (see rebin_with_dx_of in the Technical Reference) then rebinning is basically collecting redoing the experiment with a wider slit. In the case of your PSD then the resolution of the PSD would be the smallest slit width. If the data has broad features relative to the slit width then rebinning (or using a bigger slit width) should not change the results. You could simulate all this using TOPAS to see the difference. Correct rebinning should not affect parameter errors. This is a question that is not
Re:Resolution in Bruker diffractometer
Hi Shay, >Is it possible that I observed changes of 10-5A+/-10-6A in d-space? Are you sure you are asking the precision of d-spacing not of the refined lattice parameters from whole pattern? The precision of d-spacing depends on which 2Theta angle are you talking about, according to the derivative of Bragg's law below, it is reversely proportional to Tanθ, Δd/d = - Δθ/Tanθ , note Δθ is in the unit of rad. Check the vendor's Goniometer Reproducibility and you can calculate the d-spacing precision Δd/d at whatever 2θ angles. > in-situ. The sample did not move Dangerous to claim sample does not move in in-situ experiment. What is the thermal expansion coefficient of the sample holder material used in the chamber? When the holder expands at high T, your sample height changes. If you chamber is sitting on a motorised Z drive, it is possible to set the Z height change as Temperature to compensate the expansion of Chamber holder in DIFFRAC.CONFIGURATION. Hope this helps! -- Dr. Tony Wang Research Infrastructure Specialist (XRD) Central Analytical Research Facility (CARF) | Institute for Future Environments Queensland University of Technology At 2020-02-26 14:35:45, "Shay Tirosh" wrote: Is it possible that I observed changes of 10-5A+/-10-6A in d-space? Specifically, I am scanning my sample in Bruker diffractometer in Bragg-Brentano configuration with internal standard. The XRD experiment has done in-situ. The sample did not move between experiments, even not rotated. 2teta steps are 0.02deg, acquisition time for each step was 0.2sec and the detector is a multi-channel detector. I considered the random changes in the internal standard (peak at 12deg) of 10-6A as my error. The changes in the sample's reflected peak (peak at 14deg) was 10-5A. Please note that my half step is only 2teta (obviously I can improve it) is 0.01 which means a 0.005deg in teta. Do you familiar with similar work that has been intended to determine changes of 10-5A in d-space? Thanks Shay -- _ Dr. Shay Tirosh Institute for Nanotechnology & Advanced Materials Bar Ilan University Ramat Gan, 52900 Israel Phone: +972-(0)30-531-7320 Mobile: +972-(0)54-8834533 Email: stiro...@gmail.com _ ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re:Re: NIST SRM656 Analysis
Dear Matthew, I tried your data and get ~-1% amorphous. My .pro is in below link. https://www.dropbox.com/s/xuw13c91l9gq5m5/ROW.pro?dl=0 I normally do not refine Beq, which I believe gives biggest source of error in QPA... Cheers! -- Dr. Xiaodong (Tony) Wang Senior Research Infrastructure Specialist (XRD) Central Analytical Research Facility (CARF) | Queensland University of Technology Address: Level 6, P Block, Gardens Point campus, 2 George St Brisbane QLD 4000 Tel: +61 7 3138 1904 | Mob: 0452 571 680 Email: tony.w...@qut.edu.au | Web: www.qut.edu.au/ife/carf At 2022-04-13 13:00:44, "Matthew Rowles" wrote: Hi all Thanks to those that have replied off-list. I've managed to jiggle things around and get various answers. If you want an answer between -14 and +6 wt% amorphous, I can make it happen. I can either use charged atoms or not, or use thermal parameters or not. Combining those between the corundum and Si3N4, you get the following: This is using the scattering factors defined with 11 gaussians. If you use the ones defined by 9 gaussians, you get The structures I used are below. In the certificate for 656, the structures are referenced, but those structures have no thermal parameters. Does anyone know what was used in the NIST determination? phase_name "Aluminium_oxide_alpha_10425_icsd" Hexagonal( 4.759355, 12.99231) space_group "R -3 c H" site Al1 num_posns 12x 0 y 0 z 0.14772 occ Al+3 1. beq 0.318 site O1 num_posns 18x 0.3064 y 0 z 0.25occ O-2 1. beq 0.334 phase_name "ALPHA_Marchand_ICSD_26191" Hexagonal( 7.75411, 5.62034) space_group "P31c" 'atom positions from Marchand. Thermals from ICSD 77811 site Si1 num_posns 6x 0.0806 y 0.5095 z 0.3020 occ Si+4 1 beq 0.25 site Si2 num_posns 6x 0.1675 y 0.2560 z 0.0070 occ Si+4 1 beq 0.29 site N1 num_posns 2x 0 y 0 z 0 occ N1. beq 0.88 site N2 num_posns 2x =1/3; y =2/3; z 0.3500 occ N1. beq 0.46 site N3 num_posns 6x 0.0390 y 0.3860 z 0.0310 occ N1. beq 1.06 site N4 num_posns 6x 0.3190 y 0.3210 z 0.2660 occ N1. beq 0.17 phase_name "BETA_Billy_ICSD_35566" Hexagonal( 7.60633, 2.90778) space_group "P 63/m" ' structure from Billy, thermals from ICSD 170004 site Si1 num_posns 6x 0.2323 y 0.4096 z 0.25 occ Si+4 1 beq 0.231 site N1 num_posns 2x =1/3; y =2/3; z 0.25 occ N 1 beq 0.326 site N2 num_posns 6x 0.3337 y 0.0323 z 0.25 occ N 1 beq 0.314 On Tue, 12 Apr 2022 at 17:13, Matthew Rowles wrote: Hi all I've collected some more data, and am still getting spurious results, and by spurious, I mean -5 wt% amorphous in SRM-alpha-656 when quantified by the external method against SRM 676a. We had some SRM-656alpha (couldn't find any of the beta) stored in a drying oven, and some SRM676a stored in a cupboard. I collected some data using a D8 with Ni-filtered Cu and a lynx-eye detector (0.25° fixed divergence, 250 mm radius, 2x2.5° sollers). The patterns were collected consecutively (using the same program), with a single peak from SRM1976 (b, I think), acting as an intensity calibrant (the intensity didn't appreciably change), collected before, after, and between. Does anybody want to have a look at the data and see what I'm doing wrong? Data available at: https://raw.githubusercontent.com/rowlesmr/pdCIFplotter/changing-str-to-float-conversion/data/row_Cu_676a.xy https://raw.githubusercontent.com/rowlesmr/pdCIFplotter/changing-str-to-float-conversion/data/row_Cu_al656.xy Thanks Matthew On Wed, 16 Mar 2022 at 21:13, Matthew Rowles wrote: Hi List People Do any of you use NIST SRM656 in your quantitative analysis quality control? I've recently started at a new lab, and am finding it impossible to make a physically realistic model (in Topas) that gives results anywhere near correct (or at least, close to the certificate values). As an example, using the external std approach with SRM676, I've managed to calculate there is -11 wt% amorphous in the beta-656 standard. I've tried using the silicon nitride structures given in the SRM certificate, but the papers and the ICSD entries don't list any thermal parameters. I can get the same results as given on the certificate using a siroquant model, but I don't know the provenance of the HKL files used in the analysis. Thanks in advance Matthew Rowles++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re:Re: NIST SRM656 Analysis
Dear Jon, It might be just me, my current QPA practise is to micronise all samples down to 10-40 micron range and make a flat sample surface for the machine to scan. I trust the SRMs are already fine enough and Matthrew packed them well. There are roughness correction models but they may be sample (particles size) dependant hence used scaresly in my QPA practise. I am not aware of any guideline of roughness models based on controlled QPA experiments, so I am just worry the roughness models could either under- or over- correct the QPA results. Cheers! -- Dr. Xiaodong (Tony) Wang Senior Research Infrastructure Specialist (XRD) Central Analytical Research Facility (CARF) | Queensland University of Technology Address: Level 6, P Block, Gardens Point campus, 2 George St Brisbane QLD 4000 Tel: +61 7 3138 1904 | Mob: 0452 571 680 Email: tony.w...@qut.edu.au | Web: www.qut.edu.au/ife/carf At 2022-04-13 18:09:53, "Jonathan WRIGHT" wrote: >Maybe a silly question: are you assuming you have the data on an absolute >scale >in order to do these calculations? Do things like surface roughness somehow >not >matter? > >Best > >Jon > > > > >On 13/04/2022 11:56, Matthew Rowles wrote: >> Thanks Tony >> >> When I add the absorption edge correction to the silicon nitride model (and >> add >> beta-silicon nitride), it becomes -2.8 wt% amorphous; up a little due to the >> added correction and down a little due to the extra phase. >> >> If I change your al-SN thermals from 1 to those given in ICSD 77811, I get >> +4.8 >> wt% amorphous. Your atoms were already neutral, so I left them as-is. >> >> If I make all the Si-nitride phases' thermal parameters == 0, then I can get >> up >> to 8.5 wt% amorphous. >> >> In all of this, corundum is staying as charged atoms, with Al and O beqs >> fixed >> at 0.334 and 0.278. >> >> I'll have to have a go at applying the absorption edge correction; I always >> forget which parameter is which thing and have to rederive my understanding >> of >> it everytime... >> >> >> Thanks >> >> Matthew >> >> On Wed, 13 Apr 2022 at 13:58, iangie > <mailto:ian...@126.com>> wrote: >> >> Dear Matthew, >> >> I tried your data and get ~-1% amorphous. My .pro is in below link. >> >> https://www.dropbox.com/s/xuw13c91l9gq5m5/ROW.pro?dl=0 >> <https://www.dropbox.com/s/xuw13c91l9gq5m5/ROW.pro?dl=0> >> >> I normally do not refine Beq, which I believe gives biggest source of >> error >> in QPA... >> >> >> Cheers! >> >> -- >> >> *Dr. Xiaodong (Tony) Wang* >> *Senior Research Infrastructure Specialist (XRD)* >> Central Analytical Research Facility (CARF) | Queensland University of >> Technology >> *Address:* Level 6, P Block, Gardens Point campus, 2 George St Brisbane >> QLD 4000 >> *Tel:*+61 7 3138 1904 | *Mob:*0452 571 680 >> *Email:* tony <mailto:stephen.blank...@qut.edu.au>. >> <mailto:stephen.blank...@qut.edu.au>w...@qut.edu.au >> <mailto:stephen.blank...@qut.edu.au> | *Web:* www.qut.edu.au/ife/carf >> <http://www.qut.edu.au/ife/carf> >> >> >> At 2022-04-13 13:00:44, "Matthew Rowles" > <mailto:rowle...@gmail.com>> wrote: >> >> Hi all >> >> Thanks to those that have replied off-list. >> >> I've managed to jiggle things around and get various answers. If you >> want an answer between -14 and +6 wt% amorphous, I can make it >> happen. I >> can either use charged atoms or not, or use thermal parameters or >> not. >> Combining those between the corundum and Si3N4, you get the >> following: >> >> >> image.png >> This is using the scattering factors defined with 11 gaussians. >> >> If you use the ones defined by 9 gaussians, you get >> image.png >> >> The structures I used are below. In the certificate for 656, the >> structures are referenced, but those structures have no thermal >> parameters. Does anyone know what was used in the NIST determination? >> >> >> >> phase_name "Aluminium_oxide_alpha_10425_icsd" >> Hexagonal( 4.759355, 12.99231) >> space_group "R -3 c H" >> site Al1 num_posns 12x 0 y 0 z 0.14772 occ Al+3 1. beq 0.318 >
Re:Re: NIST SRM656 Analysis
Dear Mathew, Understood these values are from the SRM certificate. My .pro of the data suggests ~92% alpha, 3% beta, and ~5% Amorphous: https://www.dropbox.com/s/r2l4y0iq7d4baj7/ROW.pro?dl=0 Can you reproduce those values on the certificate? Cheers! -- Dr. Xiaodong (Tony) Wang Senior Research Infrastructure Specialist (XRD) Central Analytical Research Facility (CARF) | Queensland University of Technology Address: Level 6, P Block, Gardens Point campus, 2 George St Brisbane QLD 4000 Tel: +61 7 3138 1904 | Mob: 0452 571 680 Email: tony.w...@qut.edu.au | Web: www.qut.edu.au/ife/carf 在 2022-04-27 15:55:28，"Matthew Rowles" 写道： Yep. The sample is supposed to contain 87.4 wt% alpha-Si3N4, 3.0 wt% beta-Si3N4 and 9.6 wt% amorphous. Matthew On Tue, 26 Apr 2022 at 20:06, Martin Vickers wrote: Just a point of interest you seem to have a few impurity peaks possibly from Si6N8 (COD entry 96-210-2554 seems to match well). it's not a lot but you might want to include that phase in your quantitative calculations. Regards, Martin -- Martin Vickers Dept. of Chemistry, UCL, 20, Gordon Street WC1H 0AJ 020 7679 5592 (or ex 25592) ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re:RE: NIST SRM656 Analysis
m our students. In DIFFRAC.EVA, any powder will show some %-Amorphous if we compute crystallinity using the Default Bg model parameters (Curvature=1, Threshold=1 and No Enhancement). However, even if the powder is known to have an amorphous phase, the %-Amorphous would be =0% if we use a flat Bg with curvature=0. In Topas, the "Amor" accounts for the difference between what is identified, refined and weighted relative to internal standard; thus, Amor includes all the unknown phases, either amorphous or not-identified crystalline) and it is also Bg and many other things -sensitive. My understanding of the matter so far: refinement is instrument sensitive; therefore, it is essential to run reference materials and calibrate each instrumental setup for the purposes, model background or amorphous and save it as a scan, load in Topas, model it as an hkl phase, estimate proportions as semi-quant for the known SRM and only if a general refinement gives a reasonable amount (+-1%?) we could use it with the internal std. Also, the external method should give better results when you have a mixture of well-known references in several proportions, a kind of calibration curve. This is what Matt is going through, although this approach is time-consuming. From:rietveld_l-requ...@ill.fr On Behalf Of Matthew Rowles Sent: Tuesday, 19 April 2022, 4:20 PM To: Holger Kletti Cc: RIETVELD_L Distribution List Subject: Re: NIST SRM656 Analysis Hi Holger There is a good paper by Ian Madsen, Nikki Scarlett, and Arnt Kern about the quantification of amorphous materials - https://doi.org/10.1524/zkri.2011.1437 On the RR, I'll let the CPD know! Matthew On Thu, 14 Apr 2022 at 16:51, Holger Kletti wrote: an actual RR on amourphous contents like thos on crystalline mixtureswould really be appriciable, i don't know any publications therewith. The problem seems to exist as can be seen here, but also with internal standard method, as in personal discussions the question on achieved negative amorphous contents (internal as well as external standard method) arises from time to time. And not alway this can be solved just by variation of background polynoms or other structure related parameters. So if "anyone" would initiate such a RR i would like to join it Holger Am 14.04.2022 um 09:49 schrieb Julian Richard Tolchard: I confess that this discussion seems to validate my personal choice to treat Rietveld quantification (and especially amorphous quant) as something lying between a quantificational and semi-quantificational technique. Has anyone done a proper round-robin on amorphous quant (by any methods actually)? There have been some RR’s for crystalline mixtures I know, but I can’t remember seeing one for crystalline+amorphous samples. jools From:rietveld_l-requ...@ill.frOn Behalf Of Matthew Rowles Sent: torsdag 14. april 2022 09:03 To: Jonathan WRIGHT Cc: RIETVELD_L Distribution List Subject: Re: NIST SRM656 Analysis Hi Jon The data is put on an absolute scale through the external standard approach. The calculations assume that the QPA for corundum in NIST SRSM676a is 99.02 wt%. This scaling factor is then applied to the silicon nitride pattern. re surface roughness: The samples were backpacked against a glass surface, and the powders used as-received. I've never measured the particle size distribution of either (any!) SRM, but the certificates describe 676a as "fully disaggregated" and "grains are sub-micrometer in size and equi-axial in shape" and the 656 certificate has a particle size distribution by laser scattering, with 100% less than 5 um. In our other work, we aim to micronise to less than 10 um. Our grinding checks show that we get 100 vol% <15 um and 95 vol% <6 um. I've never used the Pitschke or Suortti roughness corrections available in Topas, and have no intuition as to the magnitude of their correction or what "proper" values should be. Matthew On Wed, 13 Apr 2022 at 18:11, Jonathan WRIGHT wrote: Maybe a silly question: are you assuming you have the data on an absolute scale in order to do these calculations? Do things like surface roughness somehow not matter? Best Jon On 13/04/2022 11:56, Matthew Rowles wrote: > Thanks Tony > > When I add the absorption edge correction to the silicon nitride model (and > add > beta-silicon nitride), it becomes -2.8 wt% amorphous; up a little due to the > added correction and down a little due to the extra phase. > > If I change your al-SN thermals from 1 to those given in ICSD 77811, I get > +4.8 > wt% amorphous. Your atoms were already neutral, so I left them as-is. > > If I make all the Si-nitride phases' thermal parameters == 0, then I can get > up > to 8.5 wt% amorphous. > > In all of this, corundum is staying as charged
Re: NIST SRM656 Analysis
Dear Matthew, I scanned our SRM α 656 using CoKα Dynamic Beam Optimation machine from 2 to 150 °2θ. https://www.dropbox.com/s/rar6sjepl9g2x2d/ROW.pro?dl=0 Using the same sample model, the derived relative wt% ratio between α and β phases are very similar to that from your CuKα data. Cheers! -- Dr. Xiaodong (Tony) Wang Senior Research Infrastructure Specialist (XRD) Central Analytical Research Facility (CARF) | Queensland University of Technology Address: Level 6, P Block, Gardens Point campus, 2 George St Brisbane QLD 4000 Tel: +61 7 3138 1904 | Mob: 0452 571 680 Email: tony.w...@qut.edu.au | Web: www.qut.edu.au/ife/carf 在 2022-04-30 11:53:46，"Matthew Rowles" 写道： Hi Tony I can't reproduce the certificate values. This is the entire point of my question. Matthew On Fri, 29 Apr 2022, 08:31 iangie, wrote: Dear Mathew, Understood these values are from the SRM certificate. My .pro of the data suggests ~92% alpha, 3% beta, and ~5% Amorphous: https://www.dropbox.com/s/r2l4y0iq7d4baj7/ROW.pro?dl=0 Can you reproduce those values on the certificate? Cheers! -- Dr. Xiaodong (Tony) Wang Senior Research Infrastructure Specialist (XRD) Central Analytical Research Facility (CARF) | Queensland University of Technology Address: Level 6, P Block, Gardens Point campus, 2 George St Brisbane QLD 4000 Tel: +61 7 3138 1904 | Mob: 0452 571 680 Email: tony.w...@qut.edu.au | Web: www.qut.edu.au/ife/carf 在 2022-04-27 15:55:28，"Matthew Rowles" 写道： Yep. The sample is supposed to contain 87.4 wt% alpha-Si3N4, 3.0 wt% beta-Si3N4 and 9.6 wt% amorphous. Matthew On Tue, 26 Apr 2022 at 20:06, Martin Vickers wrote: Just a point of interest you seem to have a few impurity peaks possibly from Si6N8 (COD entry 96-210-2554 seems to match well). it's not a lot but you might want to include that phase in your quantitative calculations. Regards, Martin -- Martin Vickers Dept. of Chemistry, UCL, 20, Gordon Street WC1H 0AJ 020 7679 5592 (or ex 25592) ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re:recommended questions to XRD supplier.
Hi Shay, Every company will answer that their product is the best. I suggest you send typical samples you are going to run in the future, to each potential company and compare the demo data quality. In your contract state that "demo data need be resonably reproducible before acceptance", so the company won't dare to cheet with high configure data. This is how I buy machines. -- Dr. Xiaodong (Tony) Wang At 2023-06-14 14:50:26, "Shay Tirosh" wrote: Dear Rietvelds, We are currently exploring the possibility of acquiring a new benchtop XRD instrument, specifically the Benchtop XRD from Malvern-Pananalytical. We have scheduled a Zoom meeting with the supplier to discuss this further. Before the meeting takes place, I would like to prepare by gathering relevant information. Could you please provide some recommended questions that we can ask the supplier? We aim to gain a comprehensive understanding of the instrument and compare its performance to other options available. Feel free to suggest and comment. Thank you for your assistance. Best regards, Shay -- Dr. Shay Tirosh Materials Scientist. With focusing on Photovoltaics, Electrochemistry, Thin film coatings, and nanotechnology. Mobile: +972-(0)54-8834533 Email: stiro...@gmail.com ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re:Re: NIST-676a
Dear Prof. Chateigner, I might need to update my knowledge. Do we need to consider texture effect for powder samples? Best Regards! -- Dr. Xiaodong (Tony) Wang Senior Research Infrastructure Specialist (XRD) Central Analytical Research Facility (CARF) | Queensland University of Technology Address: Level 6, P Block, Gardens Point campus, 2 George St Brisbane QLD 4000 Tel: +61 7 3138 1904 | Mob: 0452 571 680 Email: tony.w...@qut.edu.au | Web: www.qut.edu.au/ife/carf At 2023-11-14 19:58:05, "Daniel Chateigner 20210513" wrote: >and not textured ? > >Le 14/11/2023 à 12:56, Reinhard Kleeberg a écrit : >> Hi Jim, >> great news, would be good to have a corundum what can be modelled with >> an easier profile shape model. >> Best regards >> >> Reinhard >> >> Zitat von "Cline, James P. Dr. (Fed)" : >> >>> Hi all, >>> >>> SRM 676a consisted of Baikowski CR1. This material is of a non-ideal >>> crystallite size distribution: quite broad with tales to large >>> crystallites. SRM 676b was custom made for us by Baikowski with a >>> more uniform crystallite size distribution in the 200 nm region. We >>> are working on the certification, rather complex, see: >>> doi:10.1107/S0108767311014565 . It seems that modern beamlines don't >>> favor the large specimen size needed for our experiments. We have >>> good data from one source, we are looking for some from another as we >>> like to see results from more one machine. >>> >>> Jim >>> >>> >>> James P. Cline >>> Materials Measurement Science Division >>> National Institute of Standards and Technology >>> 100 Bureau Dr. stop 8370 [ B113 / Bldg 217 ] >>> Gaithersburg, MD 20899-8523USA >>> james.cl...@nist.gov >>> https://www.nist.gov/people/james-p-cline >>> >>> (301) 975 5793 >>> >>> -Original Message- >>> From: rietveld_l-requ...@ill.fr On Behalf >>> Of Reinhard Kleeberg >>> Sent: Monday, November 13, 2023 1:51 AM >>> To: rietveld_l@ill.fr >>> Subject: Re: NIST-676a >>> >>> We are using Baikowski CR1 >>> https://www.baikowski.com/en/serie/cr/ >>> >>> Not certified but maybe identical with SRM676a. Scale factors and >>> cell parameters found to be within the errors. Profile shape shows >>> similar features (also not an ideal material). >>> Best regards >>> Reinhard >>> >>> >>> Zitat von Matthew Rowles : >>> Hi Matej You can try IMS135 - high purity alumina. https://imst/ andards.com.au%2Fproducts%2F&data=05%7C01%7Cjames.cline%40nist.gov%7C2 d945a33db074232a69808dbe414ca9a%7C2ab5d82fd8fa4797a93e054655c61dec%7C1 %7C0%7C638354550207433666%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAi LCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=r MK%2BzDuAMv2q7U6fCpu38mzuqIrTdCiQfNDPSmB%2BQZk%3D&reserved=0 It was certified against some SRM676a we already had in the lab. Matthew On Sun, 12 Nov 2023 at 22:42, Matej Dolenec wrote: > Dear all, > > I am trying to buy NIST-676a but unfortunately unsuccessful ... I was > trying to find it on NIST, ALDRICH and other sites but the standard > is out of stock. Does anybody has any information if this standard > will be available soon and where? If not, which standard should I use > instead of NIST-676a? I was using this standard for amorphous phase > identification. > > Regrads, Matej > > ++ > Please do NOT attach files to the whole list > > > Send commands to eg: HELP as the subject with no > body text The Rietveld_L list archive is on > http://www/. > mail-archive.com%2Frietveld_l%40ill.fr%2F&data=05%7C01%7Cjames.cline% > 40nist.gov%7C2d945a33db074232a69808dbe414ca9a%7C2ab5d82fd8fa4797a93e0 > 54655c61dec%7C1%7C0%7C638354550207433666%7CUnknown%7CTWFpbGZsb3d8eyJW > IjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000 > %7C%7C%7C&sdata=nnVgkFx8mHZ%2Br%2Bng9oJ00Uz9wBy9MYDZ%2F46l%2F3%2BUGg8 > %3D&reserved=0 > ++ > > >>> >>> >>> -- >>> TU Bergakademie Freiberg >>> Dr. R. Kleeberg >>> Mineralogisches Labor >>> Brennhausgasse 14 >>> D-09596 Freiberg >>> >>> Tel. ++49 (0) 3731-39-3244 >>> Fax. ++49 (0) 3731-39-3129 >> >> >> >> ++ >> Please do NOT attach files to the whole list >> Send commands to eg: HELP as the subject with no body text >> The Rietveld_L list archive is on >> http://www.mail-archive.com/rietveld_l@ill.fr/ >> ++ >> >-- > >-- >Daniel Chateigner >Professeur Normandie Universite >http://www.ecole.ensicaen.fr/~chateign/danielc/ >-- >Editor: "Combined Analysis", Wiley-IS
Re:Pharma samples: prep and data collection
Dear Matthew, I have done several QPA for pharmaceutical formulars for QUT Health. One example is: https://doi.org/10.1016/j.ijpharm.2020.119684 They were all measured using Debye-Scherrer geometry, becasue too much penetration/absorption error in Bragg-Brentano. Many APIs have particle sizes as big as 200 micron, good for SC-XRD but not ready for PXRD. So I always gently grind APIs in mortar and pestle for 1 min to reduce particle aspect ratio, before loading into capillaries, therefore I seldom use/need PO correction. One thing below RR paper did not touched is about refining crystal structure before QPA. Many .cif structure in ICDD were solved using SC-XRD at lowT e.g. 100K. I seldom get perfect fit using those .cif structure straight away, because when the organic crystals were measured at RT, the molecules tend to stretch a little. So I always refine the API structure using Rigid Body model in TOPAS to achieve good fit (a tiny molecule distorsion could reduce Rwp a lot), before using these refined Rigid Body structure in QPA for mixtures data. Hope my two cents help. Best Regards! -- Dr. Xiaodong (Tony) Wang Senior Research Infrastructure Specialist (XRD) Central Analytical Research Facility (CARF) | Queensland University of Technology Address: Level 6, P Block, Gardens Point campus, 2 George St Brisbane QLD 4000 Tel: +61 7 3138 1904 | Mob: 0452 571 680 Email: tony.w...@qut.edu.au | Web: www.qut.edu.au/ife/carf At 2024-05-16 13:55:03, "Matthew Rowles" wrote: Hi all Are there any publications\guides on the specimen prep and data collection regimes for pharmaceutical samples? Specifically for quantitative phase analysis and phase ID. I know of the ICDD pharma round robin (Powder Diffr., Vol. 25, No. 1, March 2010). I'm a neophyte in this area, and am looking to avoid major pitfalls Matthew++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
