[3dem] K3 optimal dose rate & F20 parallel illumination

Craig Yoshioka yoshiokc at ohsu.edu
Thu Feb 14 11:57:31 PST 2019

Hi Gary,

We haven’t exhaustively tested yet, but we have been targeting around 15-20eps on the K3 and have been getting nice results.  This general range was based on the 400 -> 1500 read rate increase.

At very high-magnifications 15eps is quite a high flux, so sometimes we will go below 10eps just so that we don’t have to push very high FPS (40+) with < 1 sec exposures.  We have seen some mild pattern noise occasionally creep into images when trying to save at high frame rates.  Not sure yet if this is just our K3, or if it also seen by others.  So far it doesn’t seem to be a problem in practice, but feedback from others if they have seen this would be appreciated.


On Feb 14, 2019, at 11:45 AM, Garry P Morgan <Garry.Morgan at Colorado.EDU<mailto:Garry.Morgan at Colorado.EDU>> wrote:

thanks everyone.

On Feb 14, 2019, at 11:53 AM, Reyes, Francis <francis.reyes at thermofisher.com<mailto:francis.reyes at thermofisher.com>> wrote:

Yes it is advisable to work in nanoprobe. At parallel illumination and a 50 um C2 you should have around a 1.8um illuminated area.

Francis Reyes, Ph.D
Engineer III, Field Applications
Materials & Structural Analysis

Thermo Fisher Scientific
5350 NE Dawson Creek Drive<x-apple-data-detectors://37>
Hillsboro, OR 97124<x-apple-data-detectors://37>
Phone - +1 (720) 322-6150<tel:+1%20(720)%20322-6150>
francis.reyes at thermofisher.com<mailto:francis.reyes at thermofisher.com>

On Feb 14, 2019, at 12:36 PM, Garry P Morgan <Garry.Morgan at colorado.edu<mailto:Garry.Morgan at colorado.edu>> wrote:

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Hello all,

i’m looking for some info on the optimal dose rate for acquiring K3 movie stacks.  i would appreciate it if any of you could send me your optimum acquisition parameters for imaging cry-samples for SPA…ie, dose rate, best frame rate/number of frames, etc.

i’m also trying to figure out how to setup my low dose so that we have parallel illumination for our record images (on an FEI Tecnai F20). the problem i see is that in microprobe the beam is spread much too wide to image/expose a single hole at a time at our record mag. is it advisable to work in nano probe to get a smaller beam that is parallel? any advice on this would be appreciated.


Garry Morgan
Director  —  Boulder EM Services —  Department of MCD Biology
Campus Box 347  —  University of Colorado  —  Boulder, CO 80309
phone:  303-492-8402

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