MINIMUM ZETA: Difference between revisions
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== What is MINIMUM_ZETA? == | == What is MINIMUM_ZETA? == | ||
MINIMUM_ZETA is a parameter determining how close reflections may be to the 'blind region' of reciprocal space to still be integrated. On the detector, the blind region consists of two cones starting at the direct beam position, and extending | MINIMUM_ZETA is a parameter determining how close reflections may be to the 'blind region' of reciprocal space to still be integrated. On the detector, the blind region consists of two cones starting at the direct beam position, and extending along the spindle, to both directions. | ||
A high value (corresponding to a large blind region) is "safe" but produces lower completeness because more pixels of the detector are considered to be in the blind region. The default of 0.15 is on the safe side. I routinely use 0.1, and 0.05 turns out to still be good. | A high value (corresponding to a large blind region) is "safe" but produces lower completeness because more pixels of the detector are considered to be in the blind region. The default of 0.15 is on the safe side. I routinely use 0.1, and 0.05 turns out to still be good. | ||
== How could I check if a low value of MINIMUM_ZETA is beneficial for my data reduction? == | == How could I check if a low value of MINIMUM_ZETA is beneficial for my data reduction? == | ||
Revision as of 13:49, 9 November 2007
As always, the authoritative documentation is at http://www.mpimf-heidelberg.mpg.de/~kabsch/xds/html_doc/xds_parameters.html#MINIMUM_ZETA= !
What is MINIMUM_ZETA?
MINIMUM_ZETA is a parameter determining how close reflections may be to the 'blind region' of reciprocal space to still be integrated. On the detector, the blind region consists of two cones starting at the direct beam position, and extending along the spindle, to both directions.
A high value (corresponding to a large blind region) is "safe" but produces lower completeness because more pixels of the detector are considered to be in the blind region. The default of 0.15 is on the safe side. I routinely use 0.1, and 0.05 turns out to still be good.
How could I check if a low value of MINIMUM_ZETA is beneficial for my data reduction?
It does not hurt to use a low value of MINIMUM_ZETA (e.g. 0.05) in INTEGRATE, because in CORRECT you may still choose higher values (i.e. you don't then have to re-run INTEGRATE if you want to test a different value).
Then, run CORRECT with the low values and with higher values and compare the resulting completeness and R-factors.
For a finer evaluation, you might want to inspect the plots called 'rf.pck' of XDSSTAT .