Dear Sergei, with only 3A data and 0.1 deg frame width my first guess would be radiation damage. In that case there is little you can do - the Rmerge might just be realistic. XDS has not problem dealing with thin frames (on the contrary!) and it won't help pooling frames together.
Check out the statistics and plots from scala, they should tell you more about whether e.g. the scaling per frame increases with frame number, which is quite a sure sign of radiation damage. I would suggest to pick a new crystal and collect data with 0.5deg/frame. Tim On Fri, Nov 05, 2010 at 09:40:57AM +0100, Sergei Strelkov wrote: > Dear All, > > I am processing a dataset collected (not by me) with 0.1 degree > oscillations. > The diffraction is quite weak even though there is a clean diffraction > pattern to about 3A. > > Either Mosflm or XDS processes the data readily with +/- default settings > but both yield a high overall Rmerge of about 0.23 in the expected symmetry. > Processing in P1 yields an overall Rmerge of ~0.18, but what is > especially disappointing > is that Rmerge is as high as 0.15 at ~5A resolution already. > > The question is, how can we process the data so that the merging statistics > becomes more reasonable? > > Apparent mosaicity turns out to be ~0.5A. My naive way of thinking is > to try treating each five consecutive frames as a single 0.5 degree frame. > Does anyone have experience with this? > > Many thanks in advance, > Sergei -- -- Tim Gruene Institut fuer anorganische Chemie Tammannstr. 4 D-37077 Goettingen phone: +49 (0)551 39 22149 GPG Key ID = A46BEE1A
signature.asc
Description: Digital signature
