[3dem] Regarding Image Quality from FEI Tecnai G2 Polara

[Guenter Resch]

Hi,

> Could also additionally be a temperature problem when e.g. the objective aperture holder touches the cryo-box, also have this checked by service engineer.
> I've also had issues here from users who did not clip the grids properly. Without the clip-ring fully pushing the grid into the cartridge, contamination was horrible after just one night.

Just for the sake of completeness, one more reason for why the temperature of the sample in a Polara can be too high: if the flexible cooling braids (bundles of thin copper fibres) connecting the static cryo boxes to the shifting and tilting counter-piece where the cartridge sits are worn out (i.e., individual copper fibres are broken), the cooling efficiency is lowered by the diminished diameter. I had this once, resulting in more or less fast deterioration of sample quality (leopard skin effect).

In addition to the problems Wim mentioned, this should be checked as well if the column is split (or even via an endoscope).

Best,

	Guenter

-- 
Dr. Guenter Resch
Nexperion e.U. - Solutions for Electron Microscopy - www.nexperion.net
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