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ISa: Difference between revisions
→An estimate for the overall quality of an experimental setup
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If your crystal is good, then a and b will reflect the quality of the other components of the experimental setup (e.g. beamline stability). | If your crystal is good, then a and b will reflect the quality of the other components of the experimental setup (e.g. beamline stability). | ||
ISa is well suited to judge the quality of the experimental setup, because its value does not depend on random error, whereas the low-resolution R<sub>meas</sub> does, and is thus influenced by crystal size and exposure. If you see a high value of | ISa is well suited to judge the quality of the experimental setup, because its value does not depend on random error, whereas the low-resolution R<sub>meas</sub> does, and is thus influenced by crystal size and exposure. If you see a high value of the low-resolution R<sub>meas</sub>, you don't know if it is high because the crystal diffracted weakly, or because the beamline was broken. Conversely, a low value of ISa indicates that something is broken, no matter how small the crystal is or how weakly it was exposed. | ||
== Practical considerations == | == Practical considerations == | ||