Anchi Cheng

@biochem_fan You've got me there. My idea of what to use as IMAGE_PEDESTAL changed over time. After the publication there were people asking about the choice. I don't have a best answer there. Nor them. This is just a suggested value that worked for us.

However, I am not sure if max(mins) is better than median(mins) since max is sensitive to outliers.

MicroED data in SMV written by Leginon have two headers: LEGINON_OFFSET and IMAGE_PEDESTAL. The former is the value added to original values, while the latter is used by DIALS. pyami/numsmv.py says the latter is the "median of min values from all frames." #L57" target="_blank" rel="nofollow noopener">emg.nysbc.org/redmine/projec…

@RubinsteinJohn @IsraelF96135088 @WimJHH The most recent event when the beam intensity on camera and recover turned out to be a ground loop. Ground loop problem does not show symptom until a new current-drawing device is added to the loop, so it is not immediate.

@RubinsteinJohn @IsraelF96135088 @WimJHH We have not seen a genuine tip terracing for a few years now since XFEG. I don't recall gun current fluctuation in those cases. It is more like a loss in beam focus. You would see, the focused beam split at high mag during the event which changes the intensity into the column.

Desperate over her with our new tip on the Polara. Couple of week after installation current still oscilate between 0.25-0.90 uA what keeps the dose changing. 👇 plot reported by Appion showing mean pixel intensity per image over like 30 hours...help!! @WimJHH. Any Polara owner!?

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