[3dem] Tecnai TF20 low dose issue

[Min Su]

Dear Colleague,

I am bothered with my Tecnai TF20 for the low dose. It is appreciated  
if you would like to share your experience.

The EM is brand new. As most Joel users, we use diffraction for the  
search mode with our TF20. However we keep noticing image
shifting in the search mode (diffraction). Basically, the search and  
exposure modes can not be aligned co-centered. It is probably
due to the normalization of certain lens, I played all the combination  
of condenser, projection and objective lens, it doesn't work.

The FEI engineers told me that it is a known issue with Tecnai FEG. I  
am not convinced since I know a few groups are using the
EM in the same way as we do. They are happy with that. Also, we don't  
see problem with our T12 in such a way.

Thank you for your input.


Min

--------------------
Min Su, Ph.D.
Electron Microscopy Suite Manager
Life Sciences Institute, University of Michigan
Tel. 734-647-8193
Email.  minsu at umich.edu