FEI Talos F200i S/TEM: STEM operation (playthrough)

In this second Talos video, I demonstrate how to operate the instrument in scanning (STEM) mode with emphasis placed on obtaining high-quality atomic-resolution STEM images.
Before watching this video, I recommend you watch the following videos first (if you have not already done so):
Basic Talos operation in conventional mode:
• FEI Talos F200i S/TEM:...
Fischione instruments plasma cleaner tutorial:
• Fischione Instruments ...
Using the Ronchigram for STEM alignment:
• Performing STEM alignm...
I plan on recording at least two more Talos videos: one to cover 2-beam imaging in conventional mod and one to cover performing EDS while operating in STEM mode.
Questions, comments? Do you have a suggestion for a topic for a future video? Please let me know!

[@girlymari18]

Great series of videos! Thank you for making these, my university just purchased this TEM model, and we are in the middle of installing, and these videos are a big help in preparing to use it.

[@NicholasRudawski]

Hi Mariana: I'm glad you find the videos helpful; good luck with using your new Talos!

[@ger15100]

Thanks for the videos, Nicholas! They have served in helping me remember alignment steps after being away from our microscopes for so long due to the pandemic. Some topics you could cover in the future, if you haven't already: 4D-STEM, detectors (hybrid pixel detectors vs CCD vs CMOS) and 3D electron diffraction (and related techniques).

[@NicholasRudawski]

Glad I could help you out! Yes, we have a new system with 4D STEM so a video on that will certainly be in the works; in the interim, there is a good video here on YT from Gatan that goes into great detail on 4D so I recommend you check that out.

[@Ali-qd2th]

Many thanks Nicholas for making top-notch hands-on videos It would be nice if you can make some videos on the theoretical basics of (S)TEM, diffraction as you are indeed a nice teacher :-)

[@NicholasRudawski]

I'm glad you like the videos; thank you for the suggestion for future topics.

[@andrewkleinhenz8487]

Your videos are top drawer and are well done. Thanks for putting these together. However, It is frustrating though that they are geared for someone who pretty much knows what they are doing in the first place. Which makes them sort of moot. For a person who needs actual training they move fast using terminology that is hard to keep up with. IMO, the training video should not assume that the person pretty much knows what they are doing. I know how to operate the scope for biological imaging but have been tasked with learning STEM and EDS. I have nobody to train me. I had high hopes this video would be instrumental in getting me going. You are a masterful technician and I applaud you in all these great videos. But many folks who are starting off and need actual instruction...are out of luck. I was told the scope is aligned, however when performing these steps I am getting vastly different outcomes. I know full well I am the limiting factor here. I guess there is no replacement for actual training, which is hard to come by in today's work environment. It is a WONDERFUL set of videos, I just wish there was one out there for the technicians like me who need to start in the "slow lane" HA! If anyone knows of an actual training video on Talos STEM/EDS please let me know!

[@NicholasRudawski]

I appreciate the constructive criticism. I agree, there is a certain amount of foreknowledge implied by my videos, so that is certainly a limitation. It sounds like maybe your base alignment file may be out of sorts? My videos also assume the base alignment file is also reasonably accurate, too, though some direct tweaking will always be needed to get the most optimal results.

[@andrewkleinhenz8487]

@@NicholasRudawski Thank you kindly for your reply. I know once I receive some basic instruction I will become more skilled and proficient with time and experience. I am just starting off on "step 1". I was told by the service tech my alignment file is all set and is ready to go. Certainly I am missing something. At least I can reload the alignment file if, and when I get lost. I know these comments are beyond the scope and purpose of KZbin, but my biggest issue is when I get everything set in TEM mode and switch to STEM mode, I completely lose or cannot acquire an image on the flue camera or in velox. I will get this sorted. We all have to start somewhere. Thanks again for your great videos.

[@andrewkleinhenz8487]

I forgot to mention that if I am in SA mode in TEM with everything focused; when I switch to STEM mode the scope immediately and automatically goes to a high mag setting in diffraction mode. Confusing to me.

[@NicholasRudawski]

@@andrewkleinhenz8487 The microscope going to diffraction mode when you enter STEM mode is perfectly normal. This means the imaging system is configured to produce a diffraction pattern (in the case of STEM, a CBED pattern), which then gets projected onto your STEM detector, which is how STEM imaging works. Regarding the magnification setting when you enter STEM, it should return to what it was last set at when STEM mode was used (assuming we're talking about an FEI instrument). You can try testing this yourself to see if it works: set it to XXX kx in STEM mode, then return to TEM mode, then reenter STEM mode and it should return to XXX kx. That also assumes you are entering STEM mode by hitting the "STEM" button rather than using a FEG register; if you are using a FEG register to enter STEM mode, then it can automatically return to the mag used at the time the register was saved depending on how the FEG registers panel is set up.

[@OlivierDG_200kV]

Hi @Nicholas Rudwanski ! Thanks for the knowledge you share, Maybe you will start to gather the STEM community through this :) ? Why don't you use the FFT of the HRSTEM to correct for the astigmatism? I ask this because the FFT I saw from gold nano-P showed diagonally elongated rings, as if astigmatism was present, but I couldn't find the origin of this (Corrector seems alright, C2 centered, sample apparently stable...), any idea? Cheers,

[@NicholasRudawski]

Hi Olivier: the FFT method to correct astigmatism only works when phase contrast is present in the image, like in a conventional HR-TEM (lattice) image. There is no phase contrast in a HAADF-STEM image, so this won't work; you have to look at the Ronchigram and then fine tune in the actual image. However, if your STEM image is a BF-STEM image, you actually can use the FFT method (if part of the image is amorphous) but it's not very efficient considering the serial nature of the STEM imaging method (and remember, you adjust the condenser stigmators in STEM mode, not the objective ones). I hope this helps and I'm glad you like the videos!

[@Pkshah420]

Hey Nicholas...the interface of TEM looks blurry. I mean the writtings on tabs that you are clicking aren't visible clearly even at 1080p. Quality of video can be increased.

[@NicholasRudawski]

Yes, I completely agree; this was before I was doing direct screen capture using an ATEM mini pro and instead I was using my iPhone (like the Tecnai videos)! I think this was the last time I did a Talos video using my iPhone. If you check out any of the subsequent videos, you should be able to see the difference when I used direct screen capture.

[@saraa2636]

Thank you for the great videos and helpful responses. 1.Can I escape from the Diffraction mode and enter Imaging mode to carry out the probe alignment? 2. After Rotation Center alignment, do I need to align Beam tilt pp X/Y?

[@NicholasRudawski]

Hi Sara: sorry for the delayed reply! If you switch out of diffraction mode and into image mode you will be imaging the probe itself instead of the Ronchigram. I imagine you could use this mode for alignment, but the preferred method in the STEM community has always been to use the Ronchigram. I'd have to do some experimenting/digging to see if there is a way to align with the image that will produce similar results (I imagine it is possible). As far as the tilt pivot points, I usually don't adjust these in STEM mode; unless the person who set up the base alignments horribly messed these up, adjusting these to be perfect via direct alignments is just a minor convenience issue but doesn't in practice improve resolution so I usually just avoid it to make it easier for people I'm training. If you want to adjust, you would do so after performing rotation center, but then once you do, you will probably need to adjust the rotation center again.

[@rahulagrawal6026]

Hello and happy new year@@NicholasRudawski and Sara. I usually do S/TEM alignment by looking at the probe i.e. the diffraction button is off. This I do because, we usually deal with crystalline samples which do not have suitable amorphous region (but this method is painful). My question is what is/are the suitable magnification for doing S/TEM alignment using ronchigram? Like for TEM mode, ~65000x is a good magnification.

[@NicholasRudawski]

@@rahulagrawal6026 Happy New Year; if you are using the Ronchigram for STEM alignment, the camera length to do this is somewhat a matter of preference, but generally something larger is preferred since this will magnify the Ronchigram more and make it easier to see (though at some point the camera length can be too high and it will make it harder to align); 400 - 500 mm indicated camera length works well for me on our Talos.

[@TheBlackeagle555]

1st comment!