[3dem] Objective Astigmatism Stability

[Farzad]

Thanks a lot Sacha,

The room and the water temperature is very stable (both at 19 degrees with
less than 0.1 degrees fluctuations). Also we have installed a field
cancellation which the readings and the excitation numbers are also
completely stable at low figures. Do you have any suggestions? Maybe the
low voltage current source became unstable? Indeed i do not want to bias
you for approving my idea (lol).

Ferrie




On Tue, Aug 20, 2019, 11:42 AM Farzad <farzaad at gmail.com> wrote:

> Dear All,
>
> Anybody has any experience in measuring the stability of objective
> astigmatism in FEI F20 FEG columns (Tecnai, Talos or Glacios)? How much let
> say "astigmatism drift" is normal if we do not change anything and come
> back to the instrument after 15 minutes. I mean just imagin after
> correcting it on a carbon film area and check it on a same region and same
> optical set-up after a certain time?
>
> the sample is normal carbon grid, no magnetic or loos particles there, and
> also there is no major sample drift.
>
> Regards
>
> Farzad
>
>
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