[3dem] 626 holder temperature

Grassucci, Robert rg2502 at cumc.columbia.edu
Thu Mar 8 11:15:57 PST 2018


Hi Reinhard

It has been a while since I used a 626 but I will give it a shot.

Question a)  Heating the holder is used to bake out the zeolite or whatever cryosorb in the dewar.  This is measured somewhere on the dewar.  The temperature of the tip is measured separately and I "assume" is measured near the tip.  Older holders only had one thermocouple but yours should have 2.  (Gatan please correct me if I am wrong).  If your holder vacuum is fine, not drifting and holding for 3+ hours the temperature reach really does not matter.  I just look for results.

Question b) The spring that is mounted in a little groove in the holder can wear out  and no longer grip the ring tightly.  If you look closely at the holder you will see a hexagonal spring (wire) that grips the ring.  If this ring loses its springiness( pardon the technical jargon;-)) the ring will not clamp down on the grid.  An easy way to test this is clip a grid in and if it can be slid around without destroying the grid then your spring is damaged assuming you rings are new.
Best regards,
Bob

-----Original Message-----
From: 3dem [mailto:3dem-bounces at ncmir.ucsd.edu] On Behalf Of Reinhard Rachel
Sent: Thursday, March 08, 2018 10:43 AM
To: 3dem at ncmir.ucsd.edu
Subject: [3dem] 626 holder temperature

dear cryo-holder 626 experts, 

another question to this holder. 
We have a 626/70 Jeol version (vintage 2012) and were happy, so far. 
a closer look (yesterday, after a rest for 3 months) made us at least curious to look into details and have a careful check (hopefully, not repair?): 
a) heating the holder is done with the smart controller set for 36 to 48 hrs, to 80°C (whether good or not? remarks are welcome). How to check whether this temperature is really set? a digital thermometer - inserted into the dewar and touching the metal part, the bottom of the dewar - reads something like 41 C (set at 70 C : about 36-38 or so) ... hmm. This means either, the temperature meter of Gatan is "somewhere else" (likely the case; everything ok??), or the temperature is not reached, at all. Or anything else?
b) the clipring - when inserted - is rather loose, and not as tight as I thought it was; or, it should be. "It does not fit any more" - but is this the only explanation? are the metal parts holding the clipring 'bent'? we will try the other cliprings (we have 4 more, to try), but I also would appreciate any comments from other users, regarding this point. 

thank you in advance! 
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:
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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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