[3dem] Talos FEG Emission...

[Matthias Wolf]

Hi Duncan,

On our Talos Arctica, at 200kV and XFEG extractor at 4000V, GL5, we are getting 270uA emission. Despite still good, our FEG tip is more than 2 years old and due for replacement this week. Values will be different for SFEG.

On F3EC in counting mode, the dose rate is usually not a limiting factor. We are getting ~0.9 elec/pixel/sec dose rate at 1.12A/pixel size and spot 7 with parallel beam. But it seems you are using F2 in integrating mode.

If your FEG Emission is not stable and varies spontaneously, have FEI look at it.

  Matthias

On Sep 17, 2018, at 10:00, "duncan.sousa at rcn.com<mailto:duncan.sousa at rcn.com>" <duncan.sousa at rcn.com<mailto:duncan.sousa at rcn.com>> wrote:

Dear 3DEM,

I'm working on a Talos and the FEG emission history is highly inconsistent and currently lower than I'd like for single particle data collection on a Falcon II camera.  I'm hoping FEI Talos owners would be willing share with me their FEG emission levels. I'd also like to know what dose rate you can achieve under parallel illumination conditions at your preferred data collections:  gun lens, spot size, extraction voltage, etc.

The values I'm seeing are ~30-45uA and under parallel conditions it's difficult to achieve better than 10 e-/Ang per second with spot size 3 or greater.

Kind Regards,
Duncan


Duncan Sousa, PhD
Johns Hopkins University
School of Medicine
725 N. Wolfe Street, Hunterian 716
Baltimore, MD 21205-2185
1-410-614-1335
_______________________________________________
3dem mailing list
3dem at ncmir.ucsd.edu<mailto:3dem at ncmir.ucsd.edu>
https://mail.ncmir.ucsd.edu/mailman/listinfo/3dem
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.ncmir.ucsd.edu/pipermail/3dem/attachments/20180917/6bbeab7b/attachment.html>