[3dem] contamination...leopard?

[Tobias Furstenhaupt]

Dear colleagues,

although we dont get a high samplethroughput on our Titan Halo, we tested the Gatan ELSA holder and imaged 3 days and nights straight to get data for SPA.
I heard that side-entry TEMs (like our Halo) are more prone to contamination build up over time but we could not see a clear increase in contamination over time.
But our images suffered badly from contamination (see attached images). We see images with fuzzy contamination and also images with darker, more well defined blobs. Probably just two stages in the course of contamination buildup - or what do you think?
We also sometimes see the contamination in in two phases (attachment liquid_border). 

Am I right in assuming that we see the notorious leopard ice that is humidity contamination from a bad vacuum or slow/suboptimal handling after plungefreezing? Indeed our vacuum crashed more often than not when inserting the holder (despite greasing the O-Ring in advance)...so this could explain it. What is your opinion when you see the images?

thanks alot in advance :)
Tobias 


----------------------------------- 
Tobias Fürstenhaupt, PhD 
head of Electron Microscopy 
Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG) 
Pfotenhauerstrasse 108 
01307 Dresden, Germany 

mail: furstenh at mpi-cbg.de 
phone: (+49) (0)351 210-2690 
cell: (+49) (0)176 / 44498706 (NEW!)
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