[3dem] Airlock prepumping time

[Sharon G. Wolf]

Hello Eduardo,
We had many problems with inserting a cold cryoholder into our
Tecnai F20 until we increased the pumping time on the
turbo to 90 seconds.   Even 50 seconds wasn't always
sufficient, and the vacuum would sometimes crash upon insertion.

As long as you have the cryoholder sufficiently cooled down, the
sample temperature will not rise too much during that 90-second wait.
-Sharon


On Feb 22, 2008, at 10:32 AM, Eduardo Sanz-Garcia wrote:

> Our microscope allows to set the prepumping time for the airlock  
> when it is used in the supervisor mode.
> It was set to 90 sec and I modified to 30 sec. This makes the  
> inserting of the cryoholder faster and the temperature drops little.
> Could this short airlock prepumping time cause collateral problems  
> in the microscope?




_____________________________
Sharon Grayer Wolf, PhD.
Electron Microscopy Unit
Weizmann Institute of Science
Rehovot 76100 Israel
email: Sharon.Wolf at weizmann.ac.il
tel:  972-8-934-4421
fax: 972-8-934-4161
_____________________________