S/TEM workshop: tips, tricks, and other useful info
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- เผยแพร่เมื่อ 13 ต.ค. 2024
- In this virtual workshop (held on 04/29/22), I go over many different tips, tricks, and other useful info associated with using an S/TEM. While this workshop was conducted using our FEI F200i S/TEM, virtually all that was covered is applicable to any modern FEI S/TEM and much is also applicable to modern S/TEMs of other manufacturers as well.
Thanks for watching! Please like, subscribe, and share and let me know if you have any questions or comments. Video topic requests are always welcome and appreciated; I enjoy making these videos and wish I could make them more frequently, but the demands of my job make it tough to do so; I’m in charge of 3 S/TEMs, 2 dual beam FIB/SEM systems, and 1 SEM and this keeps me very busy!
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There was a question towards the end of the session about manually setting the value of the beta stage tilt, and I mistakenly claimed this was not possible. As was pointed out to me in a helpful comment, this can, in fact, be done. In the Stage2 control panel, select the flap-out arrow, and then select the tab labelled "Set" and any stage value (x, y, z, alpha, beta) can be specified. A big thanks to @MultiEvilOverlord for pointing this out.
This is a great resource and I'm really glad you're making these so widely available. I have an answer for the last question about manually controlling the Alpha and Beta tilts from within the software. On the Stage window, the pane with the stage map has two buttons. The upper left is the magnifying glass to change the zoom, but in the upper right there is a downward pointing triangle button. If you press this triangle button it changes the pane to give you stage controls for x, y, z, alpha, and beta. You can type in the increments you want to use and make steps in Alpha and Beta using the plus and minus buttons in that pane. So you don't have to rely on the touch sensitive buttons on the panels. At least this is the case on our Titan.
Additionally the flap-out tab of the stage box has a tab named 'set' where you can manually enter stage settings, on the Talos and Tecnai I have used.
I was completely unaware that this was possible! Thanks for pointing this out and mentioning this. Do you use this capability at all? I would think this may be useful for precise zone axis alignment, though I don't know how well this might work in practice compared to just pressing the buttons on the control panel.
I mostly use the z-height button to get as close to eucentric height as possible especially when I'm aligning the probe corrector in STEM. I want to perform my tableau at eucentric height and eucentric focus with as little defocus as possible. So being able to have a finer control over the z-height is useful. I also find that the sample drifts quite a lot in x and y on our system when tilting in Beta, so finer steps in Beta can be useful for that last bit of fine tuning the zone axis alignment on a laterally small sample.
Dear Nicholas, thanks for your work. Regarding the last question in the video, you have two another option for adjustment of tilts one is to open a navigation window by pressing small arrow button at stage tub located at the upper right corner of the map, the second is in set tub - you can find it in the third tub from the tub of reset stage and set alfa.
Good luck,
Sergei
Hi Sergei: you're welcome, and thank you for the helpful information. One of the great things about doing these videos is that I often end up learning new things myself via comments like your own. It's great to see the S/TEM community helping each other out.
I request you to make videos on reflection pattern of crystal structures taking into consideration the reflection condition, miller indices, and space groups. Thank you
Greatest video on TEM all the time!
Ha ha, maybe a bit of an overstatement, but thank you.
Our FEI Spectra does not have a probe corrector. Is there a way to adjust coma (b2) and A2 aberration?
Hi, Thank you very much for your videos. I have some questions for you
1. Which Obj Apertures are suitable for which mags? For example Obj 40 for Mag lower than 200kx and 70 for higher than 200kx?
2. For high mags like 300kx and 500kx, do we need to realign pivot points and rotation center? If we need to realign should we retract the "Obj aperture" or we shouldn't?
3. sometimes in FFT I see the circles are not a Full circle, I do not know how to explain it, for examples I see the lines on the top and bottom of FFT but I cannot see lines on the right and left, I am not sure it is because my Obj aperture is not adjusted properly or because of beam tilt? how can I make perfect full round circles?
Hi Amir:
1. For high mag work, you are usually using a specially sized objective aperture (Scherzer aperture); in this case, it happens to be the 70 um setting. At lower mag, you generally use a smaller aperture than the Scherzer aperture because you aren't trying to obtain high resolution. This is actually a great topic for a video, so thanks for asking about this (and watch for the video, eventually).
2. As long as you don't drastically change the mag from setting where you aligned the pivot points, you shouldn't need to adjust these again; same thing with the rotation center. If you switch from SA to Mh mode, then I would definitely realign the pivot points and yes, I would take the objective aperture out when aligning the pivot points.
3: It's hard to diagnose this without actually seeing the FFT; can you please send me a picture of what you are seeing? My email is in the video description. Some features you see in the FFT are simply a result of the math associated with the FFT algorithm, so that may be what is happening in your case.
Thank you so much
You're welcome.