Re: GSAS file format

Apurva ( mehta@SLAC.Stanford.EDU )
Wed, 26 Aug 1998 11:41:04 +0100

At 09:58 AM 8/26/98 -0500, you wrote:
>I am working with a difractometer output that uses *.MDI files (JADE).
>This file is almost identical to the *.RAW format accepted by GSAS.
>Several file conversion formats also will input headerless *.MDI files
>and output *.ESD and *.STD files that are compatible (?) with GSAS. Can
>anyone tell me what is the difference between the three GSAS formats?
>The current version of GSAS that runs under Windows uses what format?
>Any help is welcome. Thanks.
>

The big difference between GSAS and Jade file formats is the way in which
scan parameters are read (i.e., starting 2theta angle, increment etc.) GSAS
inputs are in centidegrees and it wants starting angle, increment/step size
and the total number of points. Jade inputs are in degrees and it wants
starting angle, final angle, and increment and the wavelength.

We convert our raw diffraction data into GSASfiles that are readable both by
GSAS and Jade. We do this by including scan information for Jade in the
first/title line and repeat the same information in centidegree in the
second line for GSAS . GSAS ignores the title and thinks of them as
GSASfiles. Jade can read these files via a costom import filter. (Not very
difficult to write.) Our gsasfiles look as follows:

BA67AJ_300K.002 11:55:37 31-JUL-98 PRB sa= 4.00 fa= 81.02 icr=0.010 LA= 1.23966
BANK 1 7702 771 CONST 400 1
20 21 26 29 30 36 18 21 25 25
20 21 21 20 18 27 23 21 29 22
14 19 31 25 22 17 24 22 18 19
24 23 29 25 20 26 28 17 23 23
23 14 16 20 19 26 31 19 16 31

(This is a scan that begins at 2th = 4 degrees {400 centidegrees}, ends at
2th = 81.02 degree, increment/step size is 0.01 degree {1 centi degree},
thus there are 7702 data points, and the x-ray wavelength was 1.23966A.

Apurva


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Apurva Mehta
SSRL/SLAC
PO Box 4349, MS 69
Stanford, CA 94309
(650) 926 4791
(650) 926 4100 - FAX

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