I am not an expert in XDS but will still put my $0.02 in:
Your new ORGX seems to be a reflection of the 2theta. In some other programs, origin is always defined at 2theta=0 and the angular (or linear, to that matter) offset is given as a parameter. I.e. software applies 2theta offset internally. If XDS works the same way, then you are confusing it by feeding in the wrong ORGX.
Hope it helps,
N.
Ruslan Sanishvili (Nukri), Ph.D.
GM/CA-CAT, Bld. 436, D007
Biosciences Division, ANL
9700 S. Cass Ave.
Argonne, IL 60439
Tel: (630)252-0665
Fax: (630)252-0667
[log in to unmask]
-----Original Message-----
From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of Jan Abendroth
Sent: Friday, July 06, 2007 4:01 PM
To: [log in to unmask]
Subject: [ccp4bb] xds, saturn94 and 2theta
Hi xds-experts,
I am struggling to get xds running for Rigaku's Saturn94 detector with 2theta offset.
Without 2theta offset, the Saturn92 input file from the xds webpage works just fine with the following modifications:
NX=2084 NY=2084 QX=0.0451 QY=0.0451 ! modified by JA
ORGX= 1024 ORGY= 1024 !Detector origin (pixels). ORGX=NX/2; ORGY=NY/2
For a 2theta offset I additionally modified the following parameters:
DIRECTION_OF_DETECTOR_X-AXIS=-0.9848 0.0 -0.1736 ! -cos2theta 0 sin2theta
ORGX= 795 ORGY= 1070 !measured in VIEW
Here the question, as the indexing according to IDXREF.LP does not pick up a good solution. Sometimes it is close, eg. for solutions with a rather good score two axes ok, one off by several Å, sometimes all cell constants are just a little off (2-3Å for a 50/50/90 Å cell).
- is the direction of the detector X-axis defined correctly (I also tried -cos2theta 0 -sin2theta)
- how does one define the origin of the detector?
a) approximate values for the center of the beam from "VIEW" (using 2084, 2084, 2, 0, l or b)
b) the refined beam center values from eg. mosflm, translated into pixels?
- any other parameters that need to be changed?
- I also tried to use only a few or plenty of images for indexing.
I know there are other programs for processing data, however, there are good reasons why I'd like to get this data set integrated with xds.
Any ideas would be greatly appreciated!
Cheers
Jan
--
Jan Abendroth
University of Washington
Institute of Biochemistry
1959 NE Pacific Street, K-426
Box 357742
Seattle, WA-98195
phone: +1-206-616-4510
fax: +1-206-685-7002
|