SEM tips?

[jyl]

I'm going on Friday to get trained on a scanning electron microscope that is on loan to my kid's school. We parent volunteers are then going to supervise the kids using the SEM during the next few months. We're supposed to bring something small and dry to try scanning. Can I bring a paring knife, d'you think? Any other tips?

(I mostly signed up for this in hopes of repeating my microscope-photos-of-knife-edges. I have no idea if a SEM is appropriate for scanning objects like that.)

If metal is a no-no, what is interesting to look at?

[aigel]

Hi John,

Metal objects are the best specimens. Most basic SEMs do not work well with non-conductive materials.
For good SEM images, specimens are often metallized in a sputter system with a few atomic layers of Au, Cu or carbon. Bugs are great specimens but are not useful unless properly prepped. Hair is also great, but won't image well without sputtering first. Maybe take a bug, it must be dry (like a fly you find behind your couch) in case they have a small sputter system to use (these are often made for the purpose of sample prep and inexpensive to run with Cu or carbon target).

An SEM will take nice images of a knife edge and you can focus in on the very tip of the edge. While the magnification may be the same than what you get in the optical microscope on the lower mags, the 3d view you get from the SEM is generally spectacular compared to an optical microscope.

I would worry that the paring knife still is too large. It may fit the chamber, but stage movement is often very limited and you may not be able to drive around to get to the knife edge properly.

I would take a razor blade, just in case. Take a brand new one and one you used a few times to shave!

Other items I can come up with:
watch parts
needle tip
guitar string

Have fun!

G

[aigel]

Razor


From:
Myth: Letting a Straight Razor Rest for a Day Sharpens It | ASR

G

[aigel]

So, did you go? Any updates? Where are the fancy pictures?

G

[jyl]

Wasted opportunity. Turned out they only have the SEM for a few weeks and I'm traveling almost every day during that time. I did one volunteer day, helped several teams of kids drive the machine, they got cool pictures. The only way to do my edge pics would have been to sharpen various razor blades to different stages, then cut and bend small sections of blade to mount on the sample tabs. Didn't have time to do this. Maybe next year. I liked learning something about the instrument and seeing stuff at 15,000X.

[GH85Carrera]

That is cool that the kids even get to see it. We were lucky to have just a couple of regular microscopes in my high school. Only one of them was fully functional.

[aigel]

Interesting. Who owns the SEM? Is it the school district or a private company or a non-profit?

Owning and running a traveling SEM for school kids would be a fun activity in early retirement!

G

[jyl]

I think it is supplied by FEI (the maker) and funded by some educational program.

The kids in this class have a lot of stuff to use. Several nice Leica optical microscopes with digital imaging software connected to Macs.

[BRPORSCHE]

Jeez. That has to be pretty sweet. There are two SEM's just down the hall from me which are made by Bruker and then we also have a QEMSCAN/FIB by FEI.

It sounds like by the way your kids class is setup they could do full blown petrographic studies. Hmmmm sounds like a nice side biz.

[aigel]

Good to hear that science education is alive and well - let's hope they don't all decide to get business degrees down the line.

G