Ice rings: Difference between revisions

Ice rings (view source)

522 bytes removed , 20 May 2013

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-* Please see [[Wishlist#Would be nice to have]]: there's a list of additional (high-) resolution ranges one might want to exclude (in [[CORRECT]]).
+* For versions of XDS after May 30,2013 one can use INCLUDE_RESOLUTION_RANGE and EXCLUDE_RESOLUTION_RANGE already in the IDXREF step. For the latter to be effective, the geometry should of course be rather accurate.
-* A currently possible way to prevent ice rings from spoiling the [[IDXREF]] step is to set "TRUSTED_REGION=0 X" for INIT, where X is calculated such that ice rings are excluded. Using Bragg's law and an approximation, we find that <br /> X = <math>\frac{Wavelength \cdot Distance} {4 \cdot NX \cdot QX}</math> should give approx. 4 Å cutoff, which should exclude all ice rings. <br /> Drawback: after successful indexing, INIT needs to be re-run with "TRUSTED_REGION=0 1.05" or so.
-A potential pitfall: the above assumes that the direct beam position is near the middle of the detector.
 * Please see [[Optimization]] for how to treat remaining ice reflections showing up as "aliens" in [[CORRECT.LP]].