Is there a fundamental upper limit for the significance I/σ(I) of observations from X-ray and neutron diffraction
1Laboratory of Crystallography, University of Bayreuth, Universitätsstrasse 30, 95447 Bayreuth, Germany. julian.henn@uni-bayreuth.de
Abstract:
The answer is yes. A fundamental limit exists, which is not strongly applicable to individual reflections but to a sufficiently large set of reflections such as any set for structure determination. The limit originates from Poisson statistics which gives a minimum (average) error. The proposed limit of significance and a proposed decrease in significance due to data processing are also tested by monitoring W = /
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