[3dem] 3dem Digest, Vol 144, Issue 2

[Anchi Cheng]

Hi, Farzad,

Even though I have not used JEOL3200 FSC for a while, since no one answered, here is my
general comment.

I don’t know what software you use or what EH correction is.  If this is aberration correction, you
won’t do it very often, then it is not an issue swapping camera to CCD for this purpose.

Yes, switching between linear and counted mode often is not the best approach.

Regarding counting mode too slow, it is not usually an issue for most tasks.  If your operation
requires live imaging, Gatan’s GMS view function is still fairly fast in counted mode, good enough for
manual astigmatism correction.  If it is slow in your software, then it depends on how your software
reads and displays the images.

If the images are taken for live manipulation, K2 counted images with a 4x bin can get very good images
within 0.5-1 second exposure and computer algorithms have no problem processing that.  The user should
also not having trouble viewing it.  If the signal is not high enough to be efficient for you, you can increase
the dose rate.  While it is important to reduce coincidence loss in the final exposure, it does not significantly impact
other tasks that requires correlation, nor impact visual inspection.

I hope this helps.

Anchi

On Aug 2, 2019, at 6:58 AM, 3dem-request at ncmir.ucsd.edu<mailto:3dem-request at ncmir.ucsd.edu> wrote:

Message: 2
Date: Fri, 2 Aug 2019 10:04:48 +0200
From: Farzad <farzaad at gmail.com<mailto:farzaad at gmail.com>>
To: 3dem at ncmir.ucsd.edu<mailto:3dem at ncmir.ucsd.edu>
Subject: [3dem] Communication Error in K2 Camera
Message-ID:
<CAM-VoOnGhn0=hRR-yFO_3kYta=KD6s8otY_qhkPFcbrh5gBhaQ at mail.gmail.com<mailto:CAM-VoOnGhn0=hRR-yFO_3kYta=KD6s8otY_qhkPFcbrh5gBhaQ at mail.gmail.com>>
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Hi all,

We have a K2 camera installed in our JEOL 3200 FSC.

The camera works nice and smooth in normal conditions but during
acquisition, after several times switching between linear mode and counting
mode it dispatches blank frames. Somebody told us that this is the inherent
problem with this camera and you should use the camera all the time in
counting mode or use the CCD for lower mags and K2 in counting mode just
for high mag.

My question is which strategy should I select? Just consider:

1- if I want to use counting mode in low mag (for EH correction) it would
be very slow.
2- If I want to switch between CCD and K2, there is a mechanical movement
which introduces a lot of vibrations and personally I feel bad about this
amount of insertions and retractions and I expect the system to fail at
some point.

I would appreciate if you teach me how you guys use K2? Is there any
similar communication problem in your system? How do you cope with it?

Best Regards,

Farzad Hamdi

Staff Scientist and Cryo-Electron Microscopy Facility Manager
Kastritis Laboratory for Biomolecular Research
Cryo-Electron Microscopy & Computational Structural Biology
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