Dear All,
I have several questions for LaB6 microscopes users:
At Burnham we have been having problems with the scope ( FEI T12) when changing the filaments. We have worked with Kimball, Denka and Applied Physics.
In some cases we see dark current. Other times we get a very low emission for the beginning and sometimes the filament last only few days.
We go over 4 or 5 filaments before we find one that works fine.

-Have anybody had similar problems?
-is anybody following a particular procedure to avoid this?
-Could somebody give the values they get for a new filament: Emission, Saturation point, and life time ( hours)

-Is anybody lowering the heat of the filament when inserting holders? We have been told that may increase the life time of the filament.

-Lat week our beam was flickering and the illumination was fluctuating without changing anything in the scope. Anybody experienced anything like that?

Thanks to all.


Wendy