[3dem] 626 holder temperature, 2

Bowman, Valorie D vdb at purdue.edu
Wed Mar 14 08:32:28 PDT 2018


Dear All,

Just one quick comment:

Zeolite cycle will heat the tip as well.. By the same process that transfers cold out to the tip from a cold dewar, the rod, the heat is transferred out from the hot inside surface of the dewar.


"Smart Heater control"  should ONLY be used to get rid of frost from the tip after use, so it doesn't just sit on the tip and corrode it. It is NOT  a quick substitute for a zeolite cycle!  Only heartache and disappointment lies down that path...

Cheers,

Valorie

Valorie Bowman

vdb at purdue.edu
765-494-5643
EM Facility Laboratory Manager/
Senior Research Electron Microscopist
Purdue Cryo EM Facility
Purdue University

________________________________________
From: 3dem <3dem-bounces at ncmir.ucsd.edu> on behalf of Reinhard Rachel <Reinhard.Rachel at biologie.uni-regensburg.de>
Sent: Wednesday, March 14, 2018 10:24 AM
To: 3dem at ncmir.ucsd.edu
Subject: [3dem] 626 holder temperature, 2

dear cryo-holder 626 users,

one week ago, I had sent out two questions on the 626 holder and I got very useful comments.
Just very few sentences to these topics as a follow-up.

a)  Heating the holder ... "is used to bake out the zeolite or whatever cryosorb in the dewar " (Bob G., NY) ---
and this is the reason why we should have done a proper heating of our holder with "Start Zeolite Cycle" - and not only with the Smart heater control.  Reading manuals resp. getting and following proper instructions may help ....
I was not aware of this difference; - on the very old 626 from ca 1986/7 (yes, it is that old), this did not exist, as far as I can remember.
Smart heater - heats the tip , and is measured at the tip (hopefully, correct); while, "zeolite cycle" heats / should heat the dewar and the zeolite ... and this is measured somewhere on the dewar.  We have not tested this, yet ....
Obviously, so far, our holder dewar vacuum was fine. The holder was not drifting too badly (at least, this was not limiting our studies), and holding for 3+ hours the temperature. Results were ok.

b) "The spring that is mounted in a little groove in the holder " (Bob G, NY) is named "Circlip" (by Gatan) and this is definitely worn out, on our holder. Can happen? Does happen. Thus, it no longer grips the clip ring:  not  tightly, not really ... (amazing that is nevertheless worked).
Repair is on its way, as our workshop is not prepared to do the exchange of the Circlip, nor do we have this part.
All Cliprings that we have, look identical and behave identically, and seem to be ok, when checked on a high-res stereo microscope.

thanks again to all ... great to get feedback.
kind regards - Reinhard


--
Prof. Dr. Reinhard Rachel
University of Regensburg
Centre for EM / Anatomy
Faculty of Biology & Preclin. Med.
Universitaetsstrasse 31
D-93053 Regensburg - Germany
tel +49 941 943 -2837, -1720
mail reinhard.rachel at biologie.uni-regensburg.de
office: VKL 3.1.29

Next microscopy conferences:
- 19th International Microscopy Congress, Sydney; 9-14 Sept 2018
http://imc19.com/
- Microscopy Conference MC2019: 1.-5. Sept 2019 in Berlin
- next Microbiol. conferences:
VAAM - Annual Conf.: 15-18 April 2018 Wolfsburg


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