CCP14
Methods, Problems and Solutions
Obtaining Digital Data From Guinier Camera Film
The CCP14 Homepage is at http://www.ccp14.ac.uk
Also refer to the Fakult�t f�r Physik - Universit�t T�bingen,
Institut f�r Kristallographie on "Automated Guinier Diffractometer" and
software such as Simref, Simpro and Maximum-Entropy Programm MEED, MEEDCAB und MEND
From: Ariel Gomez Gonzalez [email protected]
Date: Tue, 27 Apr 1999 07:27:01 -0400 (CDT)
To: RIETVELD_L Distribution List [email protected]
Subject: digital data from guinier camera film
Precedence: list
Reply-To: RIETVELD_L Distribution List [email protected]
Hi everybody,
We have a Guinier camera from which we would like to get digital data, can
anybody help us ?
Any information will be appreciated, suggestion about companies that
supplies optical densitometers or home made alternatives will also be
wellcome.
Thanks in advance,
Ariel
________________________________________________________
Ariel Gomez Gonzalez
Laboratorio de Analisis Estructural,
Departamento de Ciencia de Materiales,
IMRE, Universidad de la Habana,
La Habana 10400,
Cuba
From: [email protected] (randy hayashi)
Newsgroups: sci.techniques.xtallography
Subject: Re: special characters for crystallography
Date: 23 Apr 1997 19:23:09 GMT
Organization: u wisconsin
In article <[email protected]>, CERNY Radovan
wrote:
> Does somebody know how to write a bar over a character in Word (for
> example P-1)?
Use overstrike mode. Put commonly used stuff like -1 into your glossary.
I suppose I can send you my word glossary file, but I don't have it here at
From [email protected]
Date: Tue, 27 Apr 1999 17:23:46 +0100
To: RIETVELD_L Distribution List
Subject: Re: digital data from guinier camera film
Precedence: list
Reply-To: RIETVELD_L Distribution List
At 07:27 27/04/99 -0400, you wrote:
>We have a Guinier camera from which we would like to get digital data, can
>anybody help us ?
>Any information will be appreciated, suggestion about companies that
>supplies optical densitometers or home made alternatives will also be
>wellcome.
We use Guinier cameras a lot and employ an Agfa desktop scanner with a
transparency adaptor linked to a PC. We bought this some years ago. I
imagine these are pretty cheap these days (you can get scaners as good for
well under $100 now). NIH image provides a useful (and free) method for
converting the image into an intensity vs. 2-theta file.
Take a look at the paper:
"Digital analysis of X-ray films"
by D.C.Palmer, MINERALOGICAL MAGAZINE, 1997, Vol.61, No.3, pp.453-461
Abstract: High-resolution intensity profiles can be generated from X-ray
diffraction films using a desk-top scanner and computer image
analysis. The resulting intensity profiles have spatial resolutions
equal to, or exceeding that of modern powder diffractometers - at a
fraction of the cost. This technique provides an economical way of
preserving the information stored in libraries of old (and
deteriorating) powder diffraction films. The same technique can also
be extended to permit quantitative analysis of single-crystal
diffraction films.
Simon Redfern
Dept Earth Sciences
University of Cambridge
Downing Street
Cambridge
CB2 3EQ
UK
To: [email protected], [email protected]
Subject: Digital Data from Film
Cc: [email protected], [email protected],
[email protected], [email protected]
Precedence: list
Reply-To: RIETVELD_L Distribution List
Ariel
We use a Guinier camera which gives film strips linear in units of two
theta. Our samples are run with silicon as an internal standard. The film is
scanned in to a TIF file using a standard scanner with 600 DPI resolution. A
profile of intensity vs units of length is extracted using NIH Image
(http://rsb.info.nih.gov/nih-image) and exported as an ascii XY file. To
convert the arbitrary length scale into units of two theta I used "Winfit"
(http://www.geol.uni-erlangen.de)to peak pick the Si lines and a program
provided by Dr. Koeckerling ([email protected]) to get values
needed to convert the arbitrary length units to two theta values. The actual
conversion was done in an XCEL spreadsheet which can also render reasonable
graphics. The program "convert" (http://www.ceramics.irl.cri.nz/Convert.htm)
took the XY file format into GSAS format for Rietveld refinement. Our goal is
to use this relatively inexpensive, easily accessible camera to explore unknown
phases and design in-situ time resolved powder x-ray diffraction experiments
which we carry out with Jon Hanson at NSLS X7b using a translating image plate
camera developed by Poul Norby and co-workers.
The Rietveld list-serv has been invaluable to me over the last several
months of my graduate school career and I thank all the contributers. In
conjunction with my last post I wish to thank Lachlan Cranswick for making me
aware of multiple versions of "convert", as well as Nita Dragoe and Mark
Bowden for providing versions of this program for a Windows environment.
Patrik Dahlke has kindly provided an alternative program for conversion of XY
data to GSAS format. Stefan Krumm's "WinFit" is very nice and I wish to thank
him for its development and distribution.
Roger
Roger M. Sullivan
Department of Chemistry
North Carolina State University
[email protected]
For Debye-Scherrer Digitisation
|
Henry Barwood Powder Film Digitisation Tutorial
|