[3dem] 626 holder problems

[Zongli Li]

Dear Garry,

Looks to me the second image is from the heavily ice-contaminated area.
Based on what you described, I guess this was caused by the vacuum leak
through the cryo-shield.

Hope this helps,

Best,

Zongli

On Mon, Mar 5, 2018 at 4:22 PM, Garry P Morgan <Garry.Morgan at colorado.edu>
wrote:

> Hello list!
>
> i have yet another round of questions regarding a problem with one of my
> Gatan 626 holders.  i believe my holder tip is heating up, but i’m getting
> no indication of a temperature change on my control box.  i have attached a
> couple images…first i would like to ask if anyone can acknowledge that the
> second image (named “5hours_in_TEM”) does in fact look like a de-vitrified
> sample.
>
> the first image is what my sample looked like initially, and after ~3
> hours in the TEM; both images are from the same grid square. my nitrogen
> was topped up every 1-2 hours (so i’m confident that it didn’t run out),
> and when i noticed the change in the ice, i immediately checked the
> temperature with the control box and it was still at -184º (which is the
> usual reading for us).  likewise, there was no unusual amount of drift
> during this transformation (as one might expect if the holder was running
> out of LN2). anyway, my main questions is:  does anyone know what might be
> causing this?  i’m almost certain something is not right in my holder, but
> i just got it back (for the second time), so i’m fairly confident all the
> o-rings as well as the clip spring are (or should be) new and in good shape.
>
> one possible clue: when i first put the rod into the TEM, the column
> vacuum would not recover until i opened the shutter, at which point the
> vacuum quickly started to improve.  i guess this would indicate that the
> o-rings on the shutter assembly rod are not sealing completely…could this
> lead to a very slow/gradual warmup of the sample? later in my session,
> opening and closing the shutter had no impact on the column vac.
>
> any thoughts or possible solutions would be greatly appreciated.  and just
> for fun….can anyone guess what this sample is?
>
> thanks,
> Garry
>
>
>
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